In this article
1What is behind lactic acid2What lactic acid is for on the skin3Concentrations that work4Practical application in your routine5Smart combinations6Common mistakes with lactic acid7Pregnancy and lactation8Frequently asked questions9Sources and referencesIn short: Lactic acid is an AHA that gradually exfoliates the skin's surface and can improve texture, radiance, and superficial spots. It tends to be gentler than other acids in the same group, but can still cause irritation if you overuse it or use too high a concentration.
What is behind lactic acid
Lactic acid, whose INCI is Lactic acid, is an alpha-hydroxy acid or AHA. In cosmetics, it is primarily used for its ability to accelerate the renewal of the skin's outermost layer. Unlike other more intense exfoliants, it has a fairly balanced action: it helps with texture and dullness, but it also forms part of the skin's natural moisturizing factor.
This is important because we are not dealing with an acid that simply "peels." When well formulated, it can provide useful exfoliation without necessarily leaving the skin feeling tight. Even so, being gentler does not mean it fits into every routine or at every frequency.
What lactic acid is for on the skin
Where I see it making the most sense is in skin with uneven texture, dullness, or superficial marks. By promoting controlled shedding of the outermost cells, the skin usually looks more even and radiant with consistent use.
It can also help with rough or thickened skin. And, unlike other smaller AHAs, it is usually reasonably well-tolerated by skin that wants to start with chemical exfoliation without directly moving to more intense options.
However, it is important to have realistic expectations: it does not replace medical treatment for melasma nor does it resolve deep spots or moderate-to-severe inflammatory acne on its own.
Concentrations that work
Common cosmetic use
In products for frequent use, lactic acid is usually found in concentrations ranging from 5% to 10%. In this range, it can improve radiance, texture, and pore appearance without requiring particularly high tolerance, as long as the formula is well-designed and the pH is appropriate.
When intensity increases
From 10% to 15%, we are talking about more active formulas, more aimed at renewing texture or superficial marks, but also with a higher risk of stinging, redness, or flaking. Above that, we enter into uses that I would not recommend improvising at home if your skin is reactive or already overloaded with other active ingredients.
My opinion as a pharmacist: for most routines, starting low and sustaining over time yields better results than jumping to high percentages too soon.
Practical application in your routine
It is usually used at night, on clean and dry skin, before moisturizer. If it is your first AHA, start 2 nights a week. If after two or three weeks you don't notice irritation, you can increase to every other night.
In practice, it works well in serums, exfoliating toners, or treatment creams. You don't need to feel stinging for it to be working. In fact, when it stings too much, often your skin is telling you that you are going too fast.
And an important point: daily sun protection — and not optional. Any exfoliant that accelerates skin renewal requires a high SPF in the morning.
Smart combinations
Lactic acid usually combines well with humectants and barrier repairers such as glycerin, hyaluronic acid, panthenol, or ceramides. This combination helps to compensate for the possible tightness in the initial uses.
It can also coexist with mild antioxidants, but I would be more cautious if you are already using retinoids, other AHAs, salicylic acid, or benzoyl peroxide in the same routine. Not because the mixture is always forbidden, but because what surrounds the ingredient influences as much as the ingredient itself and the risk of irritation quickly increases when you accumulate exfoliation.
Common mistakes with lactic acid
The most common mistake is thinking that, because it is usually more tolerable than glycolic acid, you can use it without moderation. No. If persistent stinging, intense flaking, or sustained redness appears, it is advisable to space out or stop for a few days.
Another common mistake is to use it for everything. Lactic acid can be very suitable for superficial spots, radiance, or texture, but it is not always the best choice for very sensitized skin, active rosacea, or an altered barrier.
It is also advisable to review the rest of your routine. Sometimes the problem is not lactic acid, but adding it to too many powerful active ingredients at once.
Pregnancy and lactation
In cosmetics, lactic acid is generally considered a compatible option when used in usual concentrations and on intact skin. However, if you are pregnant and your skin is particularly reactive, my advice is to prioritize simple formulas and avoid experimenting with frequent exfoliation.
When it comes to intense peels or high concentrations, I prefer an individual assessment. At home, it's better to stick to conventional cosmetic formats and observe tolerance.
Frequently asked questions
Does lactic acid exfoliate more gently than glycolic acid?+
Generally, yes. It is usually better tolerated because its penetration is somewhat more gradual, although it can still irritate if the concentration is high or you use it too often.
Is it good for spots?+
It can help with superficial spots and uneven tone by promoting skin renewal. For melasma or deeper pigmentation, it usually falls short on its own.
Can I use lactic acid every night?+
It depends on the concentration, the formula, and your tolerance. If you are starting, the most sensible approach is to use it two nights a week and only increase if your skin responds well.
Can it be combined with retinol?+
It can be considered in some routines, but I wouldn't start using them together on the same night. Alternating them is usually a more prudent way to avoid irritation.
Sources and references
- Tang SC, Yang JH. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules. 2018. https://doi.org/10.3390/molecules23040863
- Kornhauser A, Coelho SG, Hearing VJ. Effects of cosmetic formulations containing hydroxyacids on sun-exposed skin: current applications and future developments. Dermatol Surg. 2010. https://doi.org/10.1111/j.1524-4725.2010.01564.x
- Green BA, Edison BL, Sigler ML, et al. The safety and efficacy of a glycolic acid and lactic acid skin care regimen. J Cosmet Dermatol. 2009. https://doi.org/10.1111/j.1473-2165.2009.00439.x
