An Overview of Lactic Acid Skin Care

Lactic acid is an alpha hydroxy acid used in over-the-counter skin care products and professional treatments. It's naturally found in milk, though the lactic acid in today's skin care products is synthetically produced. Lactic acid is used to exfoliate the skin, lighten dark spots, and improve the look of fine lines and wrinkles.

What Is Lactic Acid?

Lactic acid is a darling in the skincare world and one of the most popular alpha hydroxy acids available. It's used extensively in over-the-counter skin care and cosmeceutical products, as well as in stronger professional peels and treatments.

Lactic acid is naturally found in dairy products; it's what gives yogurt and soured milk that distinctive tang. Historically, dairy products have been used by people across the world to soften and beautify the skin. Cleopatra, legend tells us, regularly bathed in milk to keep her skin looking lovely. And it probably worked, thanks to lactic acid.

There's no need for you to hop into a tub of milk (unless you want to, milk baths are actually a nice way to pamper your skin). Today the overwhelming majority of lactic acid used in skin care products and peels is synthetically produced.

Why is lactic acid so popular? For two main reasons: First, it can create real change in the skin if used regularly. Second, it's the gentlest of all the hydroxy acids used in skin care.

Benefits of Lactic Acid

Lactic acid exfoliates the skin. It helps the older, dull cells on the skin's surface to slough away by dissolving the bonds that hold them together. Lactic acid speeds up cell turnover and stimulates cell renewal.

That's what's happening on the cellular level. But what you'll see is a brighter complexion, as well as smoother and softer skin.

All alpha hydroxy acids exfoliate and improve skin texture, but lactic acid has an extra benefit you won't get from its AHA cousins. Lactic acid helps improve the skin's natural moisture factor, or the way the skin keeps itself hydrated. Basically, lactic acid helps to keep the skin moisturized and feeling less dry.

When you use lactic acid regularly, it can also improve signs of aging. It stimulates collagen renewal and can firm your skin. Hyperpigmentation (AKA sun spots or age spots) fade and fine lines and wrinkles soften and smooth out. Lactic acid won't improve those deeper lines, though.

Interestingly, lactic acid is also the star ingredient in OTC lotions and creams for keratosis pilaris, or those "chicken skin" bumps on the backs of the arms. Lactic acid helps dissolve the plug of skin cells that build up around the hair follicle, smoothing out the bumpiness.

It's also used in topical treatments to treat eczema, psoriasis, and rosacea. You should ask your physician before adding this to your skin care routine, though.

Possible Side Effects

Even though lactic acid is gentler than other AHAs like glycolic acid and mandelic, it is still a potent treatment. There are some drawbacks to using lactic acid.

The most important thing you need to know before you start using lactic acid: it can make your skin more sensitive to the sun. As the acid sloughs away skin cells, it leaves new cells more vulnerable to UV damage.

When you start using lactic acid, you must be committed to protecting your skin from the sun. And not just on days you're actively applying your lactic acid product. Some studies have suggested that the sun sensitivity can last for two weeks after you've stopped using your product or after your peel treatment (and maybe even longer).

Use SPF 30 or higher sunscreen daily to protect your skin from sunburn and sun damage. If you don't, you could inadvertently be making the very issues you're trying to improve (like dark marks and wrinkles) worse in the long term.

Other Side Effects

Besides sun sensitivity, lactic acid can also cause skin irritation. Be on the lookout for:

  • Redness
  • Burning
  • Peeling
  • Dryness
  • Itchy skin
  • Swelling

Minor redness, burning, and itching isn't uncommon when you first apply a lactic acid product. So long as it is mild and goes away within an hour or so, you're OK.

If it's moderate to severe, doesn't go away after a short period of time, or if you have swelling or a rash, wash it off right away. Don't use the product again and call your physician for advice.

Who Should Avoid Using Lactic Acid

Lactic acid is the gentlest of the alpha hydroxy acids, so most people can use it without much issue. Still, there are reasons to stay away from this skin care ingredient.

Are you currently using topical retinoids like Retin-A or Refissa? These products are already exfoliating your skin, so there's no need to double up with a lactic acid product. If you do, you'll over-sensitize your skin. Too much of a good thing is too much.

If you're under a dermatologist's care or are using any prescription skin care medication, you should check with them before using any lactic acid treatment. It may not be appropriate for your skin.

Having super sensitive skin doesn't automatically preclude you from using lactic acid, but you take extra care until you know how your skin reacts to it. Try a low percentage product, and start off slowly. Monitor your skin carefully and scale back or stop using the product if you notice any irritation.

How To Choose OTC Lactic Acid Products

Over-the-counter lactic acid products vary widely in concentration, from 5 percent to more than 30 percent. A higher percentage isn't always better, though. Jumping right in with a high percentage product is a good way to irritate your skin.

If you've never used over-the-counter lactic acid before, start off with a very low strength product of 5 percent to 10 percent max. This will let you see how your skin reacts to lactic acid, and also allow your skin some time to get used to the acid.

You may find that after using up the product that you have, you're happy with the results you've gotten. In that case, you can stick with the strength you've been using.

If you'd like to go up in strength, do it slowly. Always monitor your skin for irritation, and if it seems like it's too much for you back it off or go back to a lower strength product.

As far as the type of lactic acid product to choose, go with something you feel comfortable using. You have a few different options.

Cleansers

Lactic acid cleansers are easy to incorporate into your skincare routine. Use them just as you would a regular cleanser. It's best to avoid the delicate eye area, though, because lactic acid cleansers have the propensity to irritate your delicate eyelids, leaving them dry, flaky, and red. Lactic acid cleansers are a good choice for sensitive skin types because you rinse them off. Lactic acid isn't setting on your skin for any length of time, and this can limit irritation.

Creams, Lotions, and Serums

For leave-on treatments, your options are moisturizing creams, lotions, and serums. Most of these suggest applying them at night rather than during the day, to minimize potential sun damage. Even so, you'll still need to use your SPF every morning. If your skin starts getting irritated with daily use, scale back and use these a couple times per week. Leave-on treatments are best for those wanting to use lactic acid long term, to steadily improve the skin and maintain.

At-Home Peels and Masks

These products are designed to deliver a stronger burst of exfoliation, and they come in higher concentrations than daily use products. You won't use these daily, but rather one to three times per week, or whatever is recommended on the product directions. At-home lactic acid peels and masks generally come in strengths of 10 percent up to 30 percent. Again, start off with a low strength and, if your skin responds well, slowly work up to higher strengths if needed.

You may find even higher "professional" lactic acid peels over the counter, with strengths of 50 percent or more. The pH of these products are buffered compared to the ones you get by the hands of a pro, but you can still get into trouble with these extra-strong peels if you don't know what you're doing. Really, it's best to leave the stronger peels to the pros.

Professional Lactic Acid Peel

Professional lactic acid peels can be done at your local day spa, medical spa, dermatology or cosmetic surgery office. Professional peels range generally range in strength from 30 percent up to 88 percent.

Superficial chemical peels can be done by an esthetician. A medical doctor must do deeper peels. Whoever is doing your peel will decide which strength is most appropriate for your initial treatments. They may go up in strength for subsequent treatments depending on your skin's needs.

Treatments, plural? Yes, a series of peels is recommended to get the full benefits of a peel. Pro lactic acid peels are a good choice if you have a specific issue you're looking to improve like dark spots, signs of aging, or texture issues.

A Word From Verywell

Lactic acid is an incredibly popular AHA treatment, and one that has a good safety track record. As long as you're listening to your skin, following the directions on the OTC products you're using, and not pushing too strong of a product too fast, you'll likely get good results with minimal irritation.

The key is to remember, no matter which lactic acid product or treatment you're using, to protect your skin from the sun. So slather on the sunscreen daily (yes, even during the winter when it's freezing and cloudy). This is one of the best ways to protect your skin from premature aging, sun spots, and skin cancer anyway, and one of the best ways to keep your skin healthy any age.

If you have any questions about which lactic acid product is right for you, ask your physician for recommendations and advice.

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Article Sources
  • Tang SC, Yang JH. "Dual Effects of Alpha-Hydroxy Acids on the Skin." Molecules. 2018 Apr 10;23(4). pii: E863. DOI: 10.3390/molecules23040863.

  • Lee CM. "Fifty Years of Research and Development of Cosmeceuticals: a Contemporary Review." Journal of Cosmetic Dermatology. 2016 Dec;15(4):527-539. DOI: 10.1111/jocd.12261.