Lactic acid
Lactic acid


Lactic acid is a type of alpha hydroxy acid (AHA). Alpha hydroxy acids are natural acids found in foods. Lactic acid comes from fermented foods.

Alpha hydroxy acids like lactic acid work by removing the top layers of dead skin cells. Lactic acid seems to increase the thickness of deeper layers of skin, promoting firmness.

People use lactic acid for dry skin. They also use it for acne, aging skin, canker sores, warts, and many other conditions, but there's no good scientific evidence to support these uses.

Don't confuse lactic acid with other alpha hydroxy acids, including citric acid, glycolic acid, malic acid, and tartaric acid. These are not the same.
When taken by mouth: There isn't enough reliable information to know if lactic acid is safe or what the side effects might be.

When applied to the skin: Lactic acid in concentrations of 10% or less is likely safe for use on the face. Concentrations of up to 15% are likely safe when used on other parts of the body, but not on the face. It is possibly unsafe when higher concentrations are used. These concentrations can cause serious skin problems and should only be used while under the care of a dermatologist.

When used in a mouthwash: Lactic acid is likely safe when used in concentrations of 5% for up to 14 days.

When applied in the vagina: Lactic acid is likely safe when used appropriately.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Lactic acid is likely safe when applied to the skin appropriately while pregnant or breast-feeding. But there isn't enough reliable information to know if lactic acid is safe to use by mouth. Stay on the safe side and stick to topical products.

Sensitive skin: Lactic acid can cause skin irritation and make certain skin conditions worse. Use cautiously in people with sensitive skin.


NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Likely effective Effectiveness definitions
  • Dry skin. Applying lactic acid, lactate, or ammonium lactate to the skin in a cream or lotion helps improve dry skin.
There is interest in using lactic acid for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Possibly effective Effectiveness definitions
Likely ineffective Effectiveness definitions
Possibly ineffective Effectiveness definitions
Insufficient evidence Effectiveness definitions

Dosing & administration

Lactic acid has most often been applied to the skin by adults in lotions, creams, and solutions containing lactic acid 4% to 15% once or twice daily for up to 6 months. Short facial peels have also been used under the supervision of a healthcare provider. Speak with a healthcare provider to find out what type of product and concentration might be best for a specific condition.

Interactions with pharmaceuticals

It is not known if Lactic Acid interacts with any medicines. Before taking Lactic Acid, talk with your healthcare professional if you take any medications.

Interactions with herbs & supplements

There are no known interactions with herbs and supplements.

Interactions with foods

There are no known interactions with foods. has licensed monographs from TRC Healthcare.
This monograph was last reviewed on 22/02/2023 11:00:00. Monographs are reviewed and/or updated multiple times per month and at least once per year.
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