Lactic Acid for Skin

In this article:
How does lactic acid work?
Lactic acid benefits
Does lactic acid repair skin?
Does lactic acid help with hyperpigmentation?
How to choose the best lactic acid for skin
What about a lactic acid serum?
How to use lactic acid for skin
Pro tips for using lactic acid
Can lactic acid be used with other skin care ingredients?
Are there any potential side effects from using lactic acid?

Exfoliating acids are one of the best ways to refine skin’s look and feel. One of the best-known categories is alpha hydroxy acids (AHAs), which includes several different skin care acids, among them lactic acid.

This well-researched AHA is included in many skin care formulas – but what sets it apart from other AHAs? Why should you consider incorporating it into your skin care routine? Read on for all the details!

How does lactic acid work?

Lactic acid is an exfoliating skin care ingredient that quickly delivers numerous benefits when applied via a well-formulated product (1). When used in a pH-correct formula (whether it’s meant to be left on skin or in a high-strength peel that’s rinsed off), lactic acid works by gently breaking the bonds that hold dead, dry skin cells to the surface (2).

These dead cells shed on their own when we’re young, but sun damage, ageing, and certain skin issues can slow or even stop this process, leading to a buildup of dead skin that creates a dull, older-looking complexion. Regular use of an alpha hydroxy acid (AHA) like lactic acid can turn this around.

As with other acids, research shows lactic acid’s ability to exfoliate effectively depends on the product’s acid concentration, with amounts between 5-12% having reliably impressive results (2). Equally important is that the product has a pH between pH 3 and 4. Although lactic acid will exfoliate skin if the pH is below 3, a pH that low can cause irritation. For example, lemon juice has a pH of 2, and as anyone who’s gotten this juice in a cut knows, it hurts! When the pH goes much above 4, the acid loses its ability to loosen the bonds holding dull, spent cells to skin’s surface.

If you’re using a rinse-off lactic acid peel, do so once weekly or every other week. Apply the peel to cleansed skin, leave on for the designated amount of time, rinse, and follow with the rest of your skin care routine. Board-certified dermatologist Dr. Debra Jaliman MD recommends lactic acid as a “gentle effective exfoliant for skin”.

Lactic acid benefits

As mentioned above, the benefits of lactic acid are numerous. It’s one of the most-researched AHAs, second only to glycolic acid. Research has revealed that…

• Lactic acid (as sodium lactate) is part of skin’s natural moisturising factor, or NMF. It’s hydrating because of its unique structure that allows it to bind water within skin (1).
• Concentrations of 5-12% help fade signs of discolouration by hastening the shedding and renewal of surface cells that have a visible buildup of excess pigment (1,2,3).
• Its discolouration-fading results also apply to post-breakout marks involving excess melanin (skin pigment) and it helps hasten the fading of pink-to-red post-breakout marks (4).
• Several studies on people have shown that in amounts between 8-12%, it improves signs of sun-damaged skin, including fine lines, wrinkles and rough texture (1,2).
• Because lactic acid strengthens skin’s barrier by encouraging it to make more ceramides, a key component of healthy skin, it’s often recommended for sensitive skin, although all skin types can use it (5).
• A little-known fact is that lactic acid is also an antioxidant; it can squelch heavy metals that may be present in water, preventing them from attacking healthy cells and releasing collagen-degrading enzymes (2,6,7).
• Lactic acid also strongly influences skin’s microbiome, helping to keep its first line of defence strong by positively interacting with a neuropeptide in skin’s surface known as Substance P, resulting in quick diffusion of signs skin is stressed (2,3,8).

Does lactic acid repair skin?

In short, the answer is yes! The benefits described above help restore skin to its natural, healthy state, mitigating damage caused by environmental factors, sun damage and breakouts. Its exfoliating abilities mimic skin’s natural desquamation (shedding) process, allowing it to slough off closer to how nature intended.

While you might not be able to eliminate 100% of the signs of damage skin has endured, it will indeed be visibly repaired to a better state!

Does lactic acid help with hyperpigmentation?

Lactic acid, like other alpha hydroxy acids, has a positive impact on improving the look of hyperpigmentation. As a surface skin exfoliant, it helps accelerate cell turnover for a temporary improvement of dark patches of skin, but it goes beyond just that. Research also shows that lactic acid can inhibit some factors that lead to hyperpigmentation, too – win–win! (9)

How to choose the best lactic acid for skin

When shopping for a lactic acid product, choose the texture that you prefer: dry skin will do best with a lactic acid cream; a lactic acid skin lotion can be great for normal to slightly dry skin; a lactic acid skin gel or fluid is perfect for combination to oily skin. A liquid format can be great for all skin types and layers well with other leave-on products.

Beyond textures, finding a well-formulated lactic acid product is key. As we touched on before, when we say well-formulated, we mean one that is at the proper pH to effectively exfoliate skin (between 3-4), contains antioxidants and skin soothing ingredients to bolster the lactic acid’s benefits, and is free from any harsh or irritating ingredients that will run counter to the positive impact the lactic acid will have on skin.

Lactic acid also works wonderfully with other AHAs. If you’re looking for advanced benefits and experiencing stubborn concerns, look for a lactic and glycolic acid product. Have sensitive skin, but still looking for visible results? Seek out a lactic and mandelic acid pairing.

What about a lactic acid serum?

Some people prefer to use a lactic acid serum. These formulas are usually stronger than “regular” exfoliant products because they combine lactic acid with other exfoliating acids, including BHA. Such serums, sometimes labeled as peels, can be perfect for more advanced concerns. For example, a lactic acid serum that contains 10% or more total acids will likely show better results on signs of uneven skin tone, discolourations and wrinkles (10).

How to use lactic acid for skin

The lactic acid exfoliant step in your skin care routine is done once or twice daily, after cleansing and toning. After application of your chosen exfoliant, you can follow with your other leave-on products, finishing with a moisturising sunscreen during the day and moisturiser (if needed) at night.

It’s fine to alternate between different types of acid exfoliants if you find this works best. You can also experiment with layering different types of skin care acids, which can be particularly worthwhile if you also struggle with enlarged, clogged pores and dehydration.

A quick note: lactic acid can be derived from dairy products, via fermentation, or made in a lab, meaning synthetic. Research has shown the synthetic form is just as effective as the natural form, and unlike the dairy-derived forms, the synthetic version is vegan (11).

Pro tips for using lactic acid

Since lactic acid has a larger molecule structure than some other alpha hydroxy acids (such as glycolic acid), it doesn’t penetrate far beyond skin’s surface. That means it’s a great option for chemical exfoliation during those times that your skin is feeling a little sensitive or extra-dry. Using lactic acid during these times means you can still reap the benefits of exfoliation even when your skin can’t tolerate more potent active ingredients.

Can lactic acid be used with other skin care ingredients?

Absolutely – we actively encourage using lactic acid with other skin care ingredients. A wealth of research shows that alpha hydroxy acids work well with other ingredients, even ones as active as retinol (11). In fact, there’s no breadth of research on what not to use with lactic acid, so feel free to experiment!

Are there any potential side effects from using lactic acid?

If you are using – as mentioned a little earlier – a lactic acid product that is formulated properly, at the correct pH and without sensitising ingredients, then you should not experience any side effects. The only exception is if you have any open wounds or abrasions on skin – this might cause some stinging. In this case, just wait for the wounds to close, and then you’re free to go about using lactic acid again.

Those with sensitive skin might also experience stinging when using lactic acid. If this is the case, look for time released lactic acid or opt for a gentler AHA, like mandelic acid.

Learn more about exfoliants.

References for this information:
1. International Journal of Dermatology, March 2019, ePublication
2. Molecules, April 2018, ePublication
3. Current Pharmaceutical Biotechnology, June 2020, pages 566–577
4. Cutis, January 2016, pages E9-E11
5. Clinical, Cosmetic, and Investigational Dermatology, October 2018, pages 491-497
6. The Journal of Dermatology, January 2006, pages 16-22
7. International Journal of Dermatology, September 2018, ePublication
8. International Journal of Cosmetic Science, April 2020, pages 116-126
9. Experimental Dermatology, October 2003, pages 43-50
10. Clinical, Cosmetic, and Investigational Dermatology, November 2010, pages 135-142
11. International Journal of Dermatology, September 2018, ePublication
12. International Journal of Medical, Health, Biomedical and Pharmaceutical Engineering, April 2015, pages 270-273