INGREDIENT

Lactic Acid Skin Care Benefits:
All You Need to Know

Lactic acid is a skin care ingredient that is an alpha hydroxy acid (AHA) and humectant that is widely used for anti-aging, hyperpigmentation, dryness, and acne. Considered the top AHA for sensitive skin types, lactic acid is a keratolytic meaning it exfoliates dead skin cells from the skin’s surface. This exfoliation reduces existing fine lines and wrinkles, fades hyperpigmentation, and clears acne. Lactic acid is also a humectant meaning it chemically attracts water molecules to itself. Lactic acid draws moisture to your newly exfoliated skin meaning it not only hydrates dry skin, but also prevents new fine lines and wrinkles from forming. Lactic acid also increases the penetration of other skin care ingredients making your other skin care products more effective. Even though lactic acid is a good option for sensitive skin, keep in mind it is still an AHA that can take some getting used to. Light stinging, redness, and burning is completely normal until your skin is conditioned to lactic acid. On the flip side, you may feel nothing, but that doesn’t mean it’s not working (just that you have less sensitive skin). Lactic acid makes skin more sensitive to UV rays, so only apply lactic acid products at night and always apply sunscreen the next day. Ready to take your skin care routine to the next level? Try lactic acid and watch her work wonders.

Fun Fact: Lactic acid is naturally occurring in both the human body (blood, muscle tissue, and skin) as well as in many fermented foods (kombucha, yogurt, cheese, soy sauce, beer, and pickles to name a few). Even though lactic acid is naturally occurring in many foods, you will not receive the skin care benefits of lactic acid unless you topically apply with a lactic acid skin care product. Unfortunately, eating a ton of cheese on wine night won't do the trick (ver sad, we know), unlike other ingredients that can be eaten and have positive effects on the skin.

WARNING: Since lactic acid is derived from dairy, people with milk allergies should avoid using this AHA.

Alternatives: If you're looking for a stronger skin care ingredient with the same benefits, a popular alternative is glycolic acid. Keep in mind that glycolic acid can have harsher side effects (redness, tingling, itching, burning) until your skin gets used to the ingredient.


 
GHS OVERVIEW
Lactic Acid

INGREDIENT CATEGORY: AHA, Chemical Exfoliant, Keratolytic, Humectant

BEST FOR TREATING: Anti-Aging, Fine Lines and Wrinkles, Dryness, Hyperpigmentation, Brightening, Acne

SKIN TYPES FOR USE: All

SAFETY: Lactic acid is safe for topical use in concentrations of up to 10% in skin care products -- however, professional treatments and chemical peels done by a licensed esthetician, dermatologist, or health care professional can have higher concentrations of lactic acid.

GHS TIP: It can take 4-6 consistent lactic acid exfoliations or chemical peels before you begin to see improvements. Light tingling and redness is normal.


 

Top 8 Lactic Acid Skin Care Benefits


Reduces Fine Lines and Wrinkles
AHA BENEFIT

Lactic acid reduces the appearance of fine lines and wrinkles by deeply exfoliating the top layer of skin. Lactic acid exfoliation has many benefits that all contribute to diminishing the appearance of fine lines and wrinkles. These varied benefits include accelerating skin cell renewal (which increases collagen and ceramide production) and hydrating the newly exfoliated skin. The combination of refreshed skin cells and better hydrated skin is both the key to reducing existing fine lines and wrinkles as well as preventing new ones from forming--and lactic acid does both. In a study on the epidermal and dermal effects of topical lactic acid, researchers found that patients topically applying lactic acid concentrations of at least 5% had increased skin firmness and thickness in the epidermis (top layer of skin) resulting in reduced fine lines and wrinkles.

Note that lactic acid (along with all other ingredients for fine lines and wrinkles) does not remove fine lines or wrinkles, but rather reduces the appearance of them. Be weary of any marketing that promises to "remove" or "erase" fine lines and wrinkles. If your fine lines and wrinkles seem to "disappear," just know the underlying fine line or wrinkle is still there deeper within the skin and will be noticeable again once the effects of your skin care routine wear off. This is why a consistent skin care routine is vital and why it's important to continuously hydrate your skin and potentially start anti-aging skin care early to prevent fine lines and wrinkles in the first place.

Fades Mild Hyperpigmentation
AHA BENEFIT

Lactic acid fades mild hyperpigmentation like dark spots, age spots, freckles, and acne scars. Additionally, lactic acid has been studied as a new therapeutic peeling agent in melasma. Lactic acid fades dark spots because hyperpigmentation is darkest on the skin's surface--the skin underneath is less pigmented (meaning it hasn't been darkened by the sun). The process of lactic acid exfoliation removes darker dead skin cells from the skin’s surface and reveals a fresh layer of skin with a more even skin tone. With consistent use, lactic acid effectively fades hyperpigmentation.

Fights Acne
EXFOLIATES & UNCLOGS PORES

Lactic acid fights acne by exfoliating dead skin cells that often clog pores and trigger breakouts. Lactic acid is a keratolytic meaning it has the ability break apart dead skin cells on the skin's surface and open any clogged pores. As a multi-purpose ingredient, lactic acid calms existing acne while also delivering anti-aging benefits. Plus, long term topical application of lactic acid has been studied as a preventive treatment for acne vulgaris. In summary, lactic acid will calm your acne today and make sure acne doesn't show up tomorrow. FYI, glycolic acid (another AHA) fights acne in the same way.

If acne is your main concern, other keratoytics include benzoyl peroxide (good for moderate to severe inflammatory acne) and azelaic acid (good for cystic acne). For oil control or sensitive skin, see salicylic acid.

The Most Hydrating AHA
SPECIFIC TO LACTIC ACID

Lactic acid is the most hydrating and nourishing AHA. Lactic acid is a humectant meaning it is a compound that chemically attracts moisture to itself. In other words, lactic acid acts like a sponge that attracts water molecules to your skin. In fact, some studies have shown lactic acid to be more hydrating than glycerin - one of the most popular humectants in skin care. Lactic acid also improves the skin's natural ability to retain existing hydration by promoting healthy lipids (see the Strengthens Lipid Layer benefit on this page). All in all, lactic acid is one of the most popular moisturizers in skin care making it a great option for babes with dry skin.

Fun Fact: the lower the pH of the lactic acid product, the greater the water absorption.

A More Gentle AHA
SPECIFIC TO LACTIC ACID

Lactic acid is milder than other AHAs (like glycolic acid) thanks to its larger molecule size. Skin care ingredients with larger molecule sizes don't penetrate the skin's surface as deeply as smaller molecule sizes (that sink further down into the skin). Thus, the larger molecular weight of lactic acid makes this AHA gentler and less irritating that other AHAs. This means lactic acid is a great option for babes with dry or sensitive skin and/or those wanting a beginner level AHA product.

Strengthens Lipid Layer
AHA BENEFIT

Lactic acid exfoliation stimulates skin cell regeneration, and during skin cell regeneration, the lipids between your skin cells also renew. This is important because lipids are the healthy, fatty, ceramides that make up the skin's barrier function. Think of your skin's barrier function as the skin's physical, bouncy barrier that separates you and your skin from the outside world: it keeps good stuff in (locks in moisture) and keeps bad stuff out. We love lactic acid because lactic acid stimulates ceramide production which leads to a stronger lipid layer, and a stronger lipid layer improves your skin's natural ability to retain hydration (a crucial part of preventing fine lines and wrinkles).

Brightens and Smooths Complexion
AHA BENEFIT

Lactic acid exfoliates the surface of your skin by breaking down the material that holds dead skin cells together. This process allows dead skin cells to shed and reveals a fresh layer of beautiful, bright, smooth skin.

Increases Penetration of Ingredients
AHA BENEFIT

Lactic acid exfoliatoin removes dead skin cells on the skin's surface which not only accelerates skin cell renewal, but also allows for deeper penetration of other skin care ingredients. With all the dead skin removed, other skin care products can better penetrate the surface of the skin, do their thing, and give you better results faster. In short, lactic acid improves the performance of your other skin care products.

 

When to Use Lactic Acid


SKIN CARE ROUTINE OPTION:
An exfoliant with lactic acid - use in evening a few times a week


when to use Lactic Acid as a chemical exfoliant in your skin care routine


 

How to Apply Lactic Acid

Nighttime only

Use lactic acid products at night only. This is very important because lactic acid (and all other AHAs) make your skin more sensitive to UV rays. Apply during your bedtime routine, and wear sunscreen in the morning to protect your newly exfoliated baby skin.

Work up to it

Mild stinging and redness is normal when first using lactic acid. Don't worry, your skin will get used to it over time. Always patch test before applying to your entire face! A patch test will help you decide if lactic acid is right for your skin. Apply a small amount of the lactic acid product in the evening to a small area on your forehead (where your facial skin is thickest). If there is mild irritation or no irritation within 24 hours, apply a thin layer of the lactic acid product to your entire face (avoid your eyes!) in the evening 1x-2x a week. If you experience harsh irritation within 24 hrs (redness, flakiness, peeling), consider trying another lactic acid product with a lower concentration. If you experience moderate to severe irritation from lactic acid, do not try glycolic acid as an alternative. Lactic acid is gentler than glycolic acid, so if you have an adverse reaction to lactic acid, we recommend steering clear of glycolic acid unless you're advised by a licensed esthetician or dermatologist.

Note: Condition your skin to get used to lactic acid by starting with a product with a lower concentration of lactic acid (start with less than 10%). Higher concentrations of lactic acid can cause more severe irritation when the skin is not acclimated to the ingredient. You might have to try a few different products that have varying concentrations of lactic acid to find what works for your skin.

Apply to entire face

Lactic acid works best when applied to your entire face (avoid eyes, lips, and mouth). Because lactic acid dissolves dead skin cells, applying to the your entire face will ensure even exfoliation. We want even skin cell renewal across your beautiful face.

Less is more

Only use a pea sized amount or less for your entire face. Too much lactic acid product can cause excessive skin irritation.

Don't over exfoliate

Exfoliate once or twice a week - NOT daily. Over exfoliating can cause severe irritation, redness, breakouts, and dryness which can even accelerate skin aging. Get excited, but don't over do it.

Don't scrub face

Lactic acid is a chemical exfoliant. It has the ability to loosen the dead skin cells on your skin’s surface without you having to scrub your skin to make it work (vs. a physical exfoliant that requires a little scrub-a-dub-dub). So don't scrub! Let the product soak in and do it’s thing.

Follow Up With...

 
Moisturizer

Apply moisturizer after your lactic acid product. Remember to always apply moisturizer twice a day (morning and evening) to protect and hydrate your newly exfoliated skin. Keeping your skin hydrated will also help prevent and soothe any potential redness or irritation from your lactic acid product. Again, slight redness and irritation is completely normal and should go away after consistent use.

Sunscreen

This is critical. The FDA recommends wearing sunscreen to prevent UV damage of lactic acid treated skin (see Guidance for Industry: Labeling for Cosmetics Containing Alpha Hydroxy Acids). Lactic acid (like all alpha hydroxy acids) exfoliates dead skin and uncovers fresh skin, but this new baby skin is extra sensitive to UV rays and susceptible to sun damage. So apply sunscreen daily. ALWAYS. Period.

 
 

Lactic Acid in Products



Lactic Acid is best for

Acne & Blemishes

Anti-Aging

Brightening

Dryness

Fine Lines and Wrinkles

Hyperpigmentation



Skin Types for Lactic Acid

All Skin Types!



Products with Lactic Acid

Chemical Peels

Cleansers

Creams/Gels

Masks

Serums



Lactic Acid Consumer Availability

Over the Counter

Professional Peels


 

Top 3 Lactic Acid Skin Care Products

We’ve put together a GHS curated selection of our favorite skin care products that contain lactic acid for anti-aging, brightening, fading hyperpigmentation, and reducing fine lines and wrinkles. We only link to products that we absolutely believe in. All the products we’ve chosen are paraben-free, sulfate-free, and phthalate-free. Remember - results won’t happen overnight. It can take 4-6 consistent lactic acid exfoliations or chemical peels before you begin to see improvements, so stay consistent with your product usage.

FARMACY BEAUTY Honeymoon Glow AHA Lactic Acid Serum

Use 2-3x weekly in PM
Apply this serum to your face and neck in the evening post cleansing and toning. Do not rinse off - only use as a mask on sensitive skin. Follow up with other non AHA serums.

Price $$$

Certified: paraben-free, sulfate-free, phthalate-free, cruelty-free


TATA HARPER Resurfacing Serum

Use 2-3x weekly in PM
Apply this serum to your face and neck in the evening post cleansing and toning. Leave on for 3 mins, then rinse with warm water. Follow up with other non AHA serums.

Price $$$$

Certified: paraben-free, sulfate-free, phthalate-free


SUNDAY RILEY Good Genes Lactic Acid Serum

Use 2-3x weekly in PM
Apply this serum to your face and neck in the evening post cleansing and toning. Do not rinse off - only use as a mask on sensitive skin. Follow up with other non AHA serums.

Price $$$$

Certified: paraben-free, sulfate-free, phthalate-free, cruelty-free, vegan, gluten-free


 
GET HEALTHY SKIN

GHS Tips

FOR LACTIC ACID

Consistency is key

Results won’t happen overnight. Consistency is key. It can take 4-6 consistent lactic acid exfoliations or chemical peels before you begin to see improvements. Be patient - good things come to those who wait. If you're not seeing improvements after 4 to 6 treatments, then we recommend trying another lactic acid product or another AHA.

Tingling is normal

Tingling or a slight burning feeling in the skin is normal when applying lactic acid topically, and it usually goes away in a few minutes. This is not an indicator of effectiveness - more tingle does not equal better. Use your best judgment. If you feel slight discomfort, don't worry about it, but if you feel like your face is on fire, then rinse it off.

Cleansers are more gentle

If you are using a cleanser with lactic acid, use at night only. Even though you're rinsing it off, lactic acid is still an ingredient that will make your skin more sensitive to the sun, so we do not recommend using a lactic acid cleanser in the morning and then going about the rest of your day in the sun. Lactic acid in a cleanser is gentle, but less effective than serums. Since you are rinsing the ingredient off immediately, you’ll get minimal benefits but also minimal skin irritation.

Serums are more effective

If you are using a lactic acid cream, gel, or serum, only apply at night. Only use lactic acid products that your skin absorbs at night. Lactic acid toners, serums, gels, and creams are more powerful than rinse off lactic acid products and make your skin more sensitive to the sun. Make sure to apply sunscreen in the morning.




 

Safety Tips


Lactic acid is FDA approved for consumers to apply topically when the concentration of the at-home skin care product is 10% or less, the final product has a pH of 3.5 or greater, and the final product is formulated in such a way that it protects the skin from increased sun sensitivity or the packaging tells consumers to use daily sun protection. Professional treatments and chemical peels administered by a dermatologist or esthetician can have higher concentrations of lactic acid.


SIDE EFFECTS OF LACTIC ACID SKIN PRODUCTS:
  • Tingling, redness or irritation
  • Dryness, itching, or peeling
  • Flaking/”frosting”
  • Purging (worsening of acne) within first few weeks

Do

Lactic acid exfoliation reveals a new layer of skin that can be easily irritated.

Wear sunscreen!

Apply moisturizer after

Avoid your eyes

Consider consulting a dermatologist - let them determine the right lactic acid concentration for you

Don't

Inflammation, peeling, and breakouts can result from the below actions.

X Don't use on inflamed acne

X Don't use on sunburned skin

X Don't use with harsh scrubs or physical exfoliants

X Don’t mix with Retin-A, Differin (adapalene), or Tazorac


FAQs about Lactic Acid


Q. What is lactic acid?

Lactic acid is a skin care ingredient that is both an alpha hydroxy acid (AHA) and humectant and is widely used for anti-aging, hyperpigmentation, dryness, and acne. Considered a top AHA for sensitive skin types, lactic acid is a keratolytic meaning it exfoliates dead skin cells from the skin’s surface. This exfoliation reduces existing fine lines and wrinkles, fades hyperpigmentation, and clears acne. Lactic acid is also a humectant meaning it chemically attracts water molecules to itself. Lactic acid draws moisture to your newly exfoliated skin meaning it not only hydrates dry skin, but also prevents new fine lines and wrinkles from forming. Lactic acid also increases the penetration of other skin care ingredients making your other skin care products more effective. Even though lactic acid is a good option for sensitive skin, it's still an AHA that can take some getting used to. Light stinging, redness, and burning is completely normal until your skin is conditioned to lactic acid. Because lactic acid makes skin more sensitive to UV rays, only apply lactic acid products at night and always apply sunscreen the next day. If you're looking for a stronger skin care ingredient with the same benefits, a popular alternative is glycolic acid, but just know that glycolic acid will also have harsher side effects (redness, tingling, itching, burning) until your skin gets used to the ingredient. Overall, lactic acid is considered a top grade AHA, and fun fact, lactic acid is naturally occurring in your skin already. Use lactic acid to take your skin care routine to the next level.

Q. What is lactic acid used for in skin care?

Lactic acid is used to treat the following skin concerns:
  • Acne
  • Anti-Aging
  • Brightening
  • Dryness
  • Fine Lines and Wrinkles
  • Hyperpigmentation

Q. How does lactic acid benefit my skin?

The top 9 lactic acid skin benefits are:
  • The most hydrating AHA
  • Strengthens lipid layer
  • Exfoliates dead skin cells
  • Reduces fine lines and wrinkles
  • Brightens and smooths complexion
  • Fades mild hyperpigmentation
  • Fights acne
  • Hydrates dry skin
  • Increases penetration of other ingredients

Q. What skin types is lactic acid good for?

Lactic acid is good for all skin types, especially sensitive skin.

Q. Is lactic acid safe for my skin?

Lactic acid is safe for topical use in concentrations of up to 10% in skin care products. However, professional treatments and chemical peels done by a dermatologist or esthetician can have higher concentrations of lactic acid.

Q. What are common side effects from applying lactic acid topically?

Tingling, redness, itching, purging (worsening of acne), and other forms of slight irritation are common side effects from applying lactic acid topically. After a few weeks, your skin should get used to lactic acid, and these reactions should be gentler or go away all together. Make sure to apply a high quality moisturizer on top of your lactic acid product. If you experience severe dryness, peeling, flaking or "frosting", consider trying another lactic acid product with a lower concentration or a different skin care ingredient. We don't recommend trying glyoclic acid if you experience severe skin irritation with lactic acid since glycolic acid is much stronger than lactic acid. If you're unsure, consult your esthetician or dermatologist. Always be sure to do a patch test on your skin before applying a new product to your entire face.

Q. How long does lactic acid take to work topically?

It can take 4-6 consistent applications of an at-home lactic acid product or professional chemical peels over the course of 1 to 2 months before you begin to see visible improvements. You may see positive signs earlier, but remember consistency is key for maximum results. Results will not happen overnight.

Q. Is lactic acid safe to use everyday?

Normally, no, it's not recommended to use lactic acid products every day, but it depends on what type of lactic acid product you're using. If you are using a rinse-off product, like a cleanser with lactic acid, then every day use can be okay. However, if you are using a leave-on product with lactic acid (like a serum, gel, cream, mask, or peel) then you should only use it 1x-3x a week. Every day will be too harsh on your skin and can do more harm than good. FYI, remember to only use lactic acid products (rinse-off or leave-on) at night only.

Q. Is tingling from lactic acid normal?

Yes, lactic acid can make your skin feel tingly or even a slightly irritated for a few minutes after application. This is completely normal, so don't panic. Slight tingling, stinging, or redness is normal, and you may feel this the first few times using lactic acid until your skin gets used to this ingredient. However, if you have severe burning or itching, try another lactic acid product with a lower concentration or consult your dermatologist or esthetician for another product to achieve the same desired effects.

Q. Can ceramide cream help skin irritation from lactic acid?

Yes, applying a ceramide cream will help soothe any skin irritation from lactic acid. According to study on the amelioration of lactic acid sensations in sensitive skin by stimulating the barrier function and improving the ceramide profile, applying ceramide cream helps soothe any skin sensitivity from lactic acid. Please and thank you.

Q. Are lactic acid peels safe?

Yes, lactic acid peels are very safe as long as you follow the directions. There are a variety of at-home lactic acid peels you can use, but if you're looking for someting stronger, consult your licensed esthetician or dermatologist. But one word of caution: Depending on the strength of the treatment as well as your skin's reaction to lactic acid, your face can be slightly red and your dead skin can peel for a few days after application. Basically, don’t get your first lactic acid peel right before any weddings, job interviews, or photo-ops.

Q. How do lactic acid peels work?

Lactic acid peels dissolve the bonds that hold dead skin cells together. As the lactic acid peel breaks down these bonds, thousands of dead skin cells can shed off your face (don't worry - it's invisible to the naked eye). The result? Vibrant, smoother, skin. Lactic acid peels reduce the appearance of fine lines and wrinkles, restore hydration, fade hyperpigmentation, and clear moderate acne. Think of it like a fresh slate of skin. Lactic acid peels range in strength, but overall, lactic acid is the gentlest alpha hydroxy acid (glycolic acid is a stronger AHA). If you're looking for something to start with and more mild, try an at-home lactic acid peel or facial. If you're interested in something stronger or have questions on which lactic acid treatment is right for your skin, consult your dermatologist or licensed esthetician.

Q. Can lactic acid burn your skin?

When following the instructions, at-home lactic acid products (concentrations of 10% or less) should not burn your skin (although a slight tingling and burning sensation is normal). On the other hand, stronger lactic acid peels (greater than 10% concentrate) that are applied professionally by a licensed esthetician or dermatologist can potentially burn your skin in a worst case scenario. We're reiterating that this is a worst case scenario, and when applied correctly, professional grade glycolic acid peels are safe. Additionally, if you happen to get a slight burn, it's normally a temporary reaction post peel. Regardless, if you're experiencing a severe adverse reaction to either an at-home lactic acid product or a professional grade lactic acid peel, consult your dermatologist or esthetician.

Q. Can lactic acid lighten your skin?

No, lactic acid is not a skin lightening (as in whitening) agent, so lactic acid will not lighten or whiten your skin. You won't turn into Snow White. Lactic acid, however, does fade darks spots and hyperpigmentation making it a safe ingredient to brighten and even your complexion. Lactic acid evens skin tone by exfoliating your skin’s surface and removing darker, melanin-stanined, dead skin cells. Lactic acid exfolation reduces the appearance of acne scars, age-related spots, sun damage, and other forms of mild hyperpigmentation without whitening the skin. Think of lactic acid like a skin care beauty blender — your same skin, but a little brighter, more even, and flawless.

Q. Can lactic acid peels cause hyperpigmentation (aka dark spots)

It depends. Low concentration lactic acid products of 10% or less (products that are safe to use at home and OTC) should not cause any hyperpigmentation. On the other hand, strong, professional-grade lactic acid peels with greater than 10% concentrations can potentially cause inflammation, and if certain areas of the skin becomes too inflamed, then hyperpigmentation can occur. Darker skin types are more prone to hyperpigmentation caused by inflammation. If you have Asian, Hispanic, or African American skin and want to try a professional-grade lactic acid peel, then consult your dermatologist or esthetician. Ask about potential hyperpigmentation side effects of your chosen treatment. Honestly, regardless of your skin type or ethnicity, you should discuss all pros and cons of professional-grade lactic acid peels (or any professional treatments for that matter) before making an educated decision on how to care for your precious skin.

In the event that you do get dark spots from a lactic acid peel, give your skin a minimum of 2-3 weeks to heal. That means no harsh treatments or ingredients (i.e. no AHAs, BHAs, retinoids), no sunshine, and making sure to apply extra moisturizer and sunscreen. Normally, hyperpigmentation caused by a chemical peel should naturally cycle off your skin within a few months, but it's best to discuss with your dermatologist or esthetician.

Q. Can lactic acid smooth deep fine lines and wrinkles?

No, lactic acid cannot completely smooth or "fill" deep fine lines and wrinkles, but don't worry, not all hope is lost. While lactic acid cannot totally erase deep fine lines and wrinkles, lactic acid can reduce the appearance of existing fine lines and wrinkles and help prevent/slow down new fine lines and wrinkles from forming. Lactic acid reduces the appearance of fine lines and wrinkles by deeply exfoliating the top layer of skin. The removal of dead skin cells flattens the skin's surface which makes deep fine lines and wrinkles appear more shallow and less noticeable. Lactic acid exfoliation also accelerates skin cell renewal, promotes faster collagen production, and strengthens the skin's natural ability to retain hydration. Lucky for us, all of these exfoliation benefits prevent and delay new fine lines and wrinkles from developing. So while lactic acid can't altogether remove deep fine lines and wrinkles, lactic acid will make your deepest creases appear softer and stimulate your skin to renew itself to prevent new ones from forming.

Q. Can lactic acid remove sun damage?

Yes, but there’s a catch. Like glycolic acid, lactic acid combats sun damage by exfoliating the outer layer of skin (the skin with the most sun damage), but in this process, lactic acid reveals freshly exfoliated skin that is more sensitive to the sun. So what does this mean? You can use lactic acid to fade hyperpigmentation and reduce fine lines and wrinkles caused by sun damage, but you must protect your newly exfoliated skin after using lactic acid--otherwise you may end up inviting even more sun damage than you started with. After using lactic acid, apply a hydrating serum or gel (to hydrate your newly exfoliated skin) followed by a more occlusive moisturizer (to seal in all the moisture). Only use lactic acid in your pm routine, and always apply sunscreen in the morning after glycolic acid treatment. We’re huge advocates of wearing sunscreen everyday, but it’s even more critical when you’re using AHAs like lactic acid.

Q. Does lactic acid make your skin photosensitive (sun sensitive)?

Yes, lactic acid makes your skin more sensitive to new sun damage. Because lactic acid exfoliates dead skin off the skin’s surface, lactic acid reveals freshly exfoliated skin, and freshly exfoliated skin is more sensitive to ultraviolet rays. In a study on the dual effects of alpha-hydroxy acids on the skin, researchers found that people applying lactic acid experienced increased sensitivity from ultraviolet radiation. So while lactic acid exfoliation helps treat existing sun damage (by fading dark spots, reducing fine lines and wrinkles, jumpstarting collagen production, and hydrating the skin), lactic acid simultaneously increases your skin’s photosensitivity. If you decide to use a lactic acid product (or any AHA products), make sure to only use at night, follow up with a hydrating serum and moisturizer, and always apply sunscreen in the morning.

Q. Does lactic acid hydrate dry skin?

Yes, lactic acid hydrates dry skin. Like all AHAs, lactic acid is a humectant meaning it chemically attracts moisture to itself, and lactic acid is the most hydrating AHA. In other words, lactic acid acts like a sponge that attracts water molecules to your skin.

Lactic acid also improves the skin's natural ability to retain existing hydration by stimulating lipid renewal. According to a study on moisturizers, lactic acid exfoliation stimulates skin cell regeneration which increases ceramide production, and increased ceramide production leads to a stronger lipid layer. This is important because lipids are the healthy, fatty, ceramides that make up the skin's barrier function. Think of your skin's barrier function as the skin's physical, bouncy barrier that separates you and your skin from the outside world: it keeps good stuff in (locks in moisture) and keeps bad stuff out. A stronger lipid layer improves your skin's natural ability to retain hydration which is also a crucial part of preventing fine lines and wrinkles.

Even though lactic acid delivers new hydration to the skin, lactic acid is not a great skin care ingredient to seal in hydration and prevent water from evaporating from your skin. This is because lactic acid is a humectant (gives your skin a drink of water) and not an occlusive (which protects that water from leaving). Lactic acid does help your skin to better protect itself from future dehydration (strengthens the lipid barrier), but lactic acid exfoliation reveals baby skin that you can think of as vulnerable and still in training. Make sure to apply a thicker lotion or moisturizer after your lactic acid product to protect your newly exfoliated skin.

Q. Is lactic acid safe for sensitive skin?

Yes, lactic acid is safe for sensitive skin. In fact, lactic acid is an alpha hydroxy acid that’s actually suitable for sensitive skin types. Some advanced anti-aging skin care ingredients (like other AHAs or retinol) can harm the barrier function in sensitive skin types, but lactic acid is gentler than these skin care ingredients. In a study on lactic and lactobionic acids as typically moisturizing compounds, researchers found that lactic acid maintains the integrity of the barrier function meaning your skin is way less likely to experience irritation compared to glycolic acid or retinol. If you have sensitive skin and you want to try anti-aging ingredients, lactic acid is a great option as you get started.

But please understand that your skin may still need to get used to lactic acid exfoliation. Light tingling, itchiness, and redness is completely normal the first couple of times you apply lactic acid (this goes for sensitive skin and normal skin types alike). But don’t sweat it! Apply a thicker cream after your lactic acid product to not only help soothe minor irritation, but also to lock in hydration for your freshly exfoliated skin (see our top creams listed here). Bonus points if your cream contains ceramides!

Q. Can lactic acid shrink pores?

No. Pore size is genetic and cannot be changed; however, pores appear bigger and expanded if they are clogged with dead skin cells or extra oil. So even though clean pores appear smaller, know that the actual size of your pores will not change - they will either be empty or full. Knowing this, be aware of any masks, astringents, or exfoliators that promise smaller pore size. These products are actually removing excess dead skin and oil (sebum) from the skin.

Q. Does lactic acid cause purging?

Yes, lactic acid can sometimes cause purging in acne prone skin. Lactic acid exfoliates dead skin cells off the skin's surface, and as a part of this process, lactic acid can open microcomedones (clogged pores from dead skin cells or excess oil and the precursors to all forms of acne) and in doing so, prevent those microcomedones from turning into full fledged acne and pimples. But sometimes, the first applications of lactic acid won't completely open existing microcomedones and purging can occur instead. Because lactic acid speeds up your skin cell turnover rate, it can sometimes accelerate the development of microcomedones turning into acne and blemishes if the exfoliation doesn't open existing microcomedones. This can cause a sudden rush of acne, but surprisingly, this is not a bad thing (and no, we aren't joking). Those microcomedones may have turned into visible acne anyways, and the lactic acid is just making them bubble up faster so they can be gone faster.

The only time you should be worried with purging of lactic acid or other ingredients that may cause purging is if you're breaking out in places you don’t normally break out or if your acne becomes inflamed. In this case, you should discontinue using the product because it’s irritating and inflaming your skin.

Q. How long does the “purge” time period last?

Purging from lactic acid should only last for up to a month. If your skin isn’t getting better after 6-8 weeks of using the product, than ditch it. Consider trying a more gentle lactic acid product with a lower concentration. If you are struggling with acne, check out our Acne & Blemishes: Causes, Treatments, & Top Ingredients page. If you have specific questions, consult your esthetician or dermatologist.

Q. What is the difference between lactic acid and glycolic acid?

Lactic acid and glycolic acid are both AHAs (alpha hydroxy acids) that fight acne, fade hyperpigmentation, brighten complexion, hyrdate the skin, promote collagen reproduction, and reduce the appearance of fine lines and wrinkles. Even though both lactic acid and glycolic acid deliver very similar benefits, lactic acid is the gentler exfoliant compared to the stronger, more powerful glycolic acid. Because lactic acid is milder than glycolic acid, lactic acid is better suited for sensitive skin and a great introductory AHA for those getting started with chemical exfoliation. But don't get it twisted and think lactic acid doesn't pack a punch. In a randomized study on the clinical efficacy of superficial peeling with 85% lactic acid versus 70% glycolic acid, both peelings were found effective in reducing fine lines and wrinkles. The benefit of lactic acid is you can get all glory without as much skin irritation.

Lactic acid is gentler than glycolic acid because it has a much larger molecule size. The bigger the molecule size, the less the skin care ingredient can penetrate deeper layers of skin. Glycolic acid has a much smaller molecule size meaning it absorbs into deeper layers of skin. Because glycolic acid molecules are able to penetrate the skin at a deeper level, glycolic acid exfoliates deeper layers of skin which is beneficial for acne, anti-aging, hyperpigmentation, and fine lines and wrinkles. This deeper exfoliation is what makes glycolic acid stronger but also what can cause harsher skin irritation for sensitive skin types. Besides the discomfort, skin irritation often dries out the skin, and dry skin is a leading contributor to the development of fine lines and wrinkles. For sensitive skin types, stronger ingredients like glycolic acid can sometimes do more harm than good.

In regards to hydration, both glycolic acid and lactic acid are humectants (skin care ingredients that attract and retain water molecules); however, lactic acid is slightly more hydrating than glycolic acid according to a study on the comparative effectiveness of alpha-hydroxy acids on skin properties. This makes lactic acid a great option for babes with dry or sensitive skin.

In summary, both glycolic acid and lactic acid are top tier AHA ingredients. If you’re trying to make a decision, it really comes down to your skin type. If your skin can handle glycolic acid, glycolic acid offers tremendous skin care benefits, but if you have dry skin, sensitive skin, or just getting started with AHAs, lactic acid offers all the same benefits as glycolic acid at a mild spicy level.

Q. What is the difference between lactic acid and salicylic acid?

Both salicylic acid and AHAs like lactic acid are chemical exfoliants that fight acne and promote faster cell turnover. However, the way they exfoliate and treat your skin is different.

Salicylic acid is a BHA (beta hydroxy acid) meaning it's oil-soluble. This means salicylic acid can get underneath and around the oil that sits in your pores to exfoliate dead skin deep within your pores. Because salicylic acid exfoliates deep into pores, it's a preferred ingredient to treat existing acne if you have oily skin. Salicylic acid is also a comedolytic meaning it prevents future whiteheads and blackheads from developing.

On the other hand, lactic acid is an AHA (alpha hydroxy acid), meaning it is water-soluble. Since oil and water don't mix, AHAs like lactic acid and glycolic acid cannot get under the oil in your pores and will only exfoliate the surface of your skin, not the dead skin underneath any oil buildup deep inside your pores. That doesn't mean lactic acid isn’t an amazing acne-fighting exfoliant--lactic acid is a keratolytic meaning it has the ability to break apart dead skin cells on the skin's surface and open any clogged pores. Opening clogged pores delivers oxygen to the pores which helps kill acne bacteria. The key difference is salicylic acid specifically removes excess oil from pores and reduces future oil production while lactic acid focuses on unclogging the surface of pores.

Another key difference between lactic acid and salicylic acid is that lactic acid is more of a multi-purpose anti-aging ingredient. Lactic acid not only combats acne, but also fades hyperpigmentation, reduces the appearance of fine lines and wrinkles, and hydrates the skin. Salicylic acid is predominantly used as an acne fighting ingredient (although its anti-inflammatory properties also help calm psoriasis). Every skin type can benefit from AHAs whereas salicylic acid is best used for acne prone skin only.

Q. Should I use both an AHA and BHA product to get the best results?

No, it is not recommended to use an AHA product and a BHA product at the same time. Since AHAs (like lactic acid or glycolic acid) are low pH exfoliants, combining an AHA with a BHA (another low pH exfoliant) can over exfoliate your skin leading to severe and harmful skin irritation like redness, dryness, flakiness, peeling, stinging, & burning. Nothing good. If you’re an overachiever and want to use both an AHA and a BHA like benzoyl peroxide in your skin care regimen, you can test using a BHA in the morning (like a salicylic cleanser) and an AHA at night (like a lactic acid serum), BUT proceed with caution. We can't overemphasize enough that you do not want to over exfoliate your skin--besides the discomfort, this can also lead to the premature development of fine lines and wrinkles. If you're considering using both ingredients at the same time, it's best to consult your dermatologist or esthetician.

Q. Can lactic acid be used with retinol?

No, we do not recommend using lactic acid with retinol. Both lactic acid and retinol are low pH ingredients that exfoliate the skin. Using multiple low pH products at the same time can over exfoliate and damage the skin's barrier function. Not only is this painful, but also leads to premature development of new fine lines and wrinkles. Some people may think to split up the ingredients between their a.m. and p.m. routines (for example, use lactic acid in the morning and retinol in the evening or vice versa), but think again. Because both lactic acid and retinol make your skin more sensitive to UV rays, neither ingredient is suitable for your morning routine. This leaves you with nightime application only, but both ingredients shouldn't be used at the same time. You could consider using lactic acid in your pm routine one day a week and choose a different night to use retinol, but again, we recommend consulting a dermatologist or licensed esthetician if you're deadset on incorporating both lactic acid and retinol into your routine. If you have further questions or concerns, please consult your dermatologist or esthetician.

Q. Can I use lactic acid and vitamin C at the same time?

Yes, it’s absolutely safe to use lactic acid and vitamin C at the same time. Both lactic acid and vitamin C are anti-aging ingredients, and even though lactic acid and vitamin C work in very different ways, they do not interfere or harm one other when used simultaneously in a skin care regimen. Lactic acid works her magic by exfoliating dead skin cells, and vitamin C is an antioxidant queen who targets free radicals. Lactic acid and vitamin C both reduce the appearance of existing fine lines and wrinkles, prevent new fine lines and wrinkles, brighten complexion, stimulate collagen production, and fade hyperpigmentation. In fact, researchers found that combining lactic acid and vitamin C increases reduction of hyperpigmentation compared to using both ingredients separately in a study on the effects of topical l(+) lactic Acid and ascorbic Acid on skin whitening.

Besides how they work, one difference between lactic acid and vitamin C is lactic acid hydrates the skin while vitamin C does not. Similarly, lactic acid fights mild acne while vitamin C does not (but FYI vitamin C is still safe for acne prone skin). Another difference between the two is lactic acid makes the skin more sensitive to UV rays (so it should only be applied at night) and vitamin C actually fights UV damage (so it should be applied morning and night). Finally, even though lactic acid is a gentle AHA, it can still cause slight skin irritation while, on the other hand, vitamin C very rarely causes any form of skin irritation. Both ingredients are safe for all skin types, though if you have extremely sensitive skin, lactic acid may take some getting used to. All in all, lactic acid and vitamin C reinforce one another and are the perfect power couple for any skin care regimen.

Q. Can lactic acid treat psoriasis?

Yes, lactic acid can help treat psoriasis. Lactic acid, along with other alpha hydroxy acids like glycolic acid, exfoliate thickened skin, and in a study on Keratolytics and Emollients and Their Role in the Therapy of Psoriasis: a Systematic Review, researchers found that lactic acid and glycolic acid both had positive exfoliation effects when treating psoriasis. Lactic acid exfoliation works by lactic acid molecules penetrating the skin’s surface and delivering hydration between dead skin cells. This extra water absorbs between the layers of thick, dead skin and loosens the bonds between the dead skin cells (FYI, the tight bonds between the dead skin cells are what hold thick layers of dead skin in place on yo’ face). Think of your skin cells as a wall of bricks held together by mortar. Lactic acid helps dissolve the mortar between dead skin cell bricks that are ready to go. Without being bonded to one another, all the dead skin cells can finally release off of your skin.

Q. Can lactic treat lifa disease (frictional dermal melanonis)?

Yes, lactic acid can treat lifa disease (frictional dermal melanonis). In a study on Lactic Acid as a New Therapeutic Peeling Agent in the Treatment of Lifa Disease (Frictional Dermal Melanosis), researchers found that hyperpigmentation improved in all patients in the study and the results were statistically significant. They found that there was general skin lightening including lightening of age spots as a result of applying lactic acid.

Q. Do lactic acid skin care products expire?

Yes. Look for the expiration date or a POA (prescribed period after opening) which tells you how long the product is good after it’s been opened. When in doubt, toss it out - the following are signs that your product has expired:
  • The product has changed color or texture
  • There is a strange scent coming from the product
  • If you have swipe pads, they will begin to dry out
  • If you have peels or masks, they will begin to feel more irritating on your skin
If your lactic acid product has expired, do not use it - expired products can cause skin irritation, bacterial infection, or breakouts.

Q. What are common names used to identify lactic acid on an ingredient list for skin care products?
  • Lactic Acid
  • D-Lactic Acid
  • L-Lactic Acid

  • Salts of lactic acid also used in skin care products:
    • Ammonium Lactate
    • Calcium Lactate
    • Potassiu Lactate
    • Sodium Lactate
    • TEA-Lactate

    Esters of lactic acid also used in skin care products:
    • Methyl Lactate
    • Ethyl Lactate
    • Butyl Lactate
    • Lauryl Lactate
    • Myristyl Lactate
    • Cetyl Lactate


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