Confused about when and how to use lactic acid in your skincare routine? Here’s a master class on this gentle, radiance-boosting ingredient.

There’s a reason (okay, a bunch of reasons) that we chose 10% lactic acid as the star of our Overnight Brightening Mask. Lactic acid, in the form of sodium lactate, occurs naturally in our skin as a key component of the skin’s natural moisturizing factor, or NMF–the protective layer that keeps our skin hydrated. Lactic acid is also hydrating thanks to its unique humectant properties that attract moisture and helps to strengthen the skin barrier. In addition, lactic acid is an exfoliant that speeds up cell turnover as well as stimulating cell renewal to help even out skin texture and improve the appearance of hyperpigmentation–a common occurrence in pregnancy. Best of all, this all-round skincare superstar is not only suitable for all skin types including dry skin, sensitive skin, and darker skin tones, but lactic acid is safe for use during pregnancy.

Here, all the answers to your questions about this genius glow-enhancer—which may well become your new favorite skincare ingredient.

Q: What is lactic acid?

A: Lactic acid is part of a group of non-abrasive exfoliants called alpha hydroxy acids, or AHAs. All alpha hydroxy acids work by dissolving the “glue” that allows dead cells to stick to the surface of the skin. This layer is protective, though it can easily build up and clog pores or give the complexion a dull appearance. Lactic acid is the kinder, gentler cousin of glycolic acid, and was traditionally derived from sour milk—which is why legendary beauty Cleopatra took ritual milk baths. The lactic acid we use comes from newer biotechnology that creates a cleaner, plant-derived vegan version through fermentation.

Q: What does lactic acid do for the skin?

A: Lactic acid is a brilliant multi-tasker. When lactic acid loosens those dead cells on the surface of the skin, it increases cell turnover. This is important, because our natural ability to slough off dead cells slows with age, leading to rough skin texture, clogged pores and breakouts. Lactic acid is a superstar at keeping pores clean and reducing the appearance of fine lines and discoloration, but did you know that it’s also the only AHA that moisturizes skin? That’s right, in addition to all that skin-smoothing and clarifying, lactic acid is a moisturizer as its humectant properties help to increase water retention (aka, hydration). And that’s a beautiful thing for any skin type.

Q: My skin gets irritated by acids. What makes lactic acid gentler?

A: If you’ve been afraid to try acids after a bad experience with glycolic acid, give lactic acid a try. It’s gentler because the molecular size of lactic acid is larger than glycolic acid, which means it works more on the skin’s surface than penetrating beneath the layers like glycolic acid does. And because it also has moisturizing properties, lactic doesn’t have the same adverse effect on the skin’s protective moisture barrier like the more aggressive glycolic.

Q: I have dark spots and discoloration. Is lactic acid safe during pregnancy?

A: Good news! Unlike other skincare ingredients that aren’t safe to use during pregnancy—like retinol, benzoyl peroxide, and hydroquinone— using lactic acid while pregnant has been deemed safe due to its low penetration levels, making it an excellent option for combating dullness and discoloration when you’re expecting. Because we made our Overnight Brightening Mask with pregnant and postpartum moms’ delicate skin in mind, we bolstered our lactic acid with moisturizing skin-calmers to make sure it was as gentle and non-drying as possible.

Q: When should you use lactic acid in your skincare routine?

A: Lactic acid is truly the acid for everyone, even for those with sensitive skin. Apply it up to 2–3 times a week at night to freshly washed skin, and wake up to a glowier, clearer-looking complexion in the morning. Remember that, as with any AHA, lactic acid can make you more sun-sensitive, so apply sunscreen during the day; our Mineral Sunscreen SPF 50 is a sheer, blendable, moisturizing formula that works beautifully for all ages and skin types, and is made with 100% mineral non-nano zinc oxide for safe, gentle UV protection.

The most important thing with lactic acid is to see how your skin reacts to it. Start slowly and watch to see how skin feels afterwards, which will give you the best idea of how often to use it. Also, never use it on open blemishes or on skin that is irritated or sunburned.

Q: Does lactic acid play well with other skincare ingredients?

A: Yes! Lactic acid can be used with moisturizing and hydrating ingredients like squalane, glycerin, and hyaluronic acid (all of which get along beautifully in our Overnight Brightening Mask). If you have sensitive skin, lactic acid may not play well with other AHAs like glycolic acid, and definitely rethink the retinol (which should already be off-limits if you’re pregnant). If you’re using a vitamin C product, be sure to use it in the morning and keep the lactic acid to nighttime.  And again, always use mineral sunscreen during the day. It’s a good thing to do anyway!

And keep in mind…

• Although lactic is one of the gentler (but effective!) acids, just remember more isn’t always more. Start off slowly and watch your skin. It will tell you when to pull back and when to up the usage.
• Because it’s an acid, you may feel a little tingling sensation when you first apply, which can be amplified if you do it while your skin is damp. If you find it too uncomfortable, wait a few minutes after washing your face and make sure your skin is dry before putting on the product.

Cleopatra was onto something when it comes to radiantly smooth skin— though thankfully you don’t have to deal with a bathtub-ful of sour milk to get that famous glow.

The information provided by Pipette is intended solely for educational purposes. The information is not to be used for medical diagnostic purposes and is not intended to serve as a recommendation for treatment and/or management of any medical/surgical condition. Most of all, this information should not be used in place of a physician or other qualified health provider. If you believe you or your child have a medical condition, please contact your physician immediately.