If there is one thing to know about skincare acids, it is that different acids support different skin concerns. Glycolic acid is known for boosting radiance, while salicylic acid is often used to exfoliate and clear congested pores.
Even lesser-known acids, such as antioxidant-rich phytic acid, have earned a place in modern skincare.
Among them, lactic acid stands out for its gentle yet effective action. It is often well suited to sensitive skin and offers a range of benefits, from mild exfoliation to improved hydration and smoother-looking skin.
What is lactic acid?
Lactic acid is a type of alpha hydroxy acid (AHA) commonly used in skincare. AHAs are acids found in natural sources such as fruits, vegetables and fermented ingredients, and they are valued for their ability to exfoliate the skin’s surface.
Lactic acid is also naturally present in the body and plays a role in maintaining the skin’s pH balance. In cosmetic formulas, it is often derived through the fermentation of ingredients such as milk, sugarcane, apples, grapes or glucose syrup obtained from corn.
In skincare, the strength of lactic acid depends on several factors, including:
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the concentration used
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the size of the molecule
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the overall pH of the formula
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the way it is combined with other active ingredients
What does lactic acid do for the skin?
Lactic acid is known for being a gentle exfoliating ingredient that can help improve the look and feel of the skin without being as aggressive as some stronger acids.
1. It gently exfoliates dead skin cells
One of the key benefits of lactic acid is its keratolytic action, which means it helps loosen and remove dead skin cells from the surface of the skin. This supports natural cell turnover and can leave the skin looking smoother, fresher and more radiant.
2. It helps improve skin texture and tone
By encouraging exfoliation, lactic acid can help soften rough texture, refine uneven areas and improve overall skin clarity. With regular use, skin may appear more even, brighter and more polished.
3. It supports hydration
Unlike some exfoliating acids, lactic acid is also known for its moisturising properties. It can help attract water to the skin and support the skin barrier, making it especially useful in routines for dry or dehydrated skin.
4. It may help reduce the appearance of fine lines
Lactic acid can help smooth the skin’s surface, which may reduce the appearance of fine lines and early signs of ageing. By supporting renewal and improving hydration, it can contribute to a plumper, healthier-looking complexion.
5. It can help with congestion and blemish-prone skin
Because lactic acid helps remove built-up dead skin cells and keep pores clearer, it may also support skincare routines designed for oily or blemish-prone skin. It is often found in products formulated for skin affected by breakouts, uneven texture or post-acne marks.
6. It helps maintain the skin’s pH balance
Lactic acid is also used in many cosmetic products as a pH-adjusting ingredient. Supporting the skin’s natural pH may help reinforce its protective barrier and overall resilience.
Is lactic acid suitable for sensitive skin?
Lactic acid is often considered one of the gentler exfoliating acids, which is why it is frequently recommended for people with sensitive, dry or normal skin.
That said, suitability always depends on the formulation and concentration. Lower concentrations are generally better for beginners or those with delicate skin, while stronger formulations may be more appropriate for those targeting concerns such as pigmentation, roughness or visible sun damage.
Who can benefit from lactic acid?
Lactic acid may be a good option for people concerned with:
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dull skin
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rough texture
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post-acne marks
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mild congestion
Because it combines exfoliating and hydrating benefits, it can be a useful ingredient for many skin types when used appropriately.
How to use lactic acid in your routine
Lactic acid is commonly found in serums, creams, toners and cleansers. For leave-on products, it is often best used in the evening.
A sensible way to introduce it is to start slowly:
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begin with two to three applications per week
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use a lower concentration at first
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gradually increase frequency as your skin adjusts
On non-acid days, focus on nourishing and hydrating ingredients to support the skin barrier.
What should you not mix with lactic acid?
To reduce the chance of irritation, it is usually best not to use lactic acid in the same routine as other strong active ingredients such as:
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benzoyl peroxide
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other exfoliating acids
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high-strength vitamin C, depending on the formula and your skin tolerance
If you are using multiple active ingredients, alternate them across different evenings unless advised otherwise by a skin professional.
Do you need SPF when using lactic acid?
Yes. Because lactic acid exfoliates the skin, it can make the skin more sensitive to sun exposure. Daily sunscreen is essential when using lactic acid, even if you only apply it at night.
Final thoughts
Lactic acid is a versatile skincare ingredient that offers a balance of gentle exfoliation and hydration. It can help improve texture, brighten dull-looking skin, support a smoother complexion and fit comfortably into many skincare routines, including those designed for sensitive skin.
As with any active ingredient, the key is to introduce it gradually, use it consistently, and pay attention to how your skin responds.