Lactic Acid

AHA (Alpha Hydroxy Acid)
Benefits
Hair Structure ImprovementHair GrowthRejuvenationHealingCleansingSoothingLighteningMoisturizingAcne fighting

What is Lactic Acid?

Lactic acid is an alpha hydroxy acid, a naturally occurring organic carboxylic acid produced via fermentation of sugars by lactic acid bacteria or found in sour milk. In skincare formulations, it serves primarily as a chemical exfoliant in peels, toners, serums, and creams, alongside roles in moisturizers and cleansers. Its larger molecular structure allows slower skin penetration compared to smaller AHAs, enabling milder exfoliation by dissolving intercellular lipids that bind dead skin cells, which encourages natural cell turnover for improved texture. Simultaneously, it functions as a humectant, binding water to the skin's surface layers to enhance moisture retention and plumpness, while also aiding pH balance in products for optimal stability and efficacy.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1-4 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Exfoliant
Helps remove dead surface cells to smooth texture and enhance radiance; can be physical (particles) or chemical/enzymatic depending on the ingredient type.
Fragrance ingredient
Contributes scent character and/or masks base odors, shaping the overall sensory experience of the formula (subject to allergen and IFRA considerations).
Humectant
Attracts and holds water in the stratum corneum, boosting hydration and plumpness; commonly used in moisturizers, cleansers, and hair conditioners.
PH adjuster
Raises or lowers pH to the target range, supporting ingredient performance, preservative efficacy, stability, and user comfort.
Skin conditioning agent
Maintains skin softness, smoothness, and flexibility.
Buffering agent
Maintains the pH stability of a formulation.

Benefits

Promotes smoother texture through gentle exfoliation

Enhances hydration as a humectant

Supports acne-prone skin management

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals with dry or dull skin seeking renewal
Those with very sensitive skin
Those looking for mild exfoliation and brightening
People prone to irritation from acids
People with acne or uneven tone
Individuals with open wounds or eczema

Safety Notes

  • Start with low frequencies and patch test to assess tolerance
  • Pair with sun protection due to increased sun sensitivity

Frequently Asked Questions about Lactic Acid

What makes lactic acid different from other AHAs?

Its larger molecule allows gentler, slower penetration for milder exfoliation.

Can lactic acid help with dry skin?

Yes, it draws moisture to the skin while removing dull surface cells.

Is lactic acid suitable for beginners?

Often yes, due to its milder nature, but introduce gradually.