Lactic acid peel: effects, studies, formulation knowledge
What is lactic acid?
Lactic acid peeling consists of L(+)-lactic acid (INCI: Lactic Acid). It is an alpha hydroxy acid (AHA) that has exfoliating, moisture-binding, and pH-regulating properties. In cosmetics, it is often used in the form of a lactic acid peel to remove dead skin cells and promote skin renewal.
Physicochemical data:
– INCI: Lactic Acid
– Chemical name: 2-hydroxypropionic acid
– Molecular formula: C₃H₆O₃
– Molar mass: 90.08 g/mol
– CAS No. (L(+)-form): 79-33-4
– pK_a: approx. 3.86
– Solubility: completely water-soluble
– Appearance: colorless to slightly yellowish liquid
Lactic acid is available as L(+)- and D(-)-isomers. In cosmetics, the physiologically relevant L(+)-lactic acid is predominantly used.
Where does lactic acid occur naturally?
Lactic acid is a natural component of the human body and part of the Natural Moisturizing Factor (NMF). It is produced during anaerobic glycolysis (muscle metabolism), regulates the skin’s acid mantle and supports barrier homeostasis. This means that it is biochemically closely linked to skin physiology.
How does a lactic acid peel work?
A professionally formulated lactic acid peel works through several mechanisms:
Keratolysis: Dissolves corneodesmosomes → accelerated exfoliation.
2. Hydration: Lactic acid has a hygroscopic effect and increases skin moisture.
3. Barrier stimulation: Promotes ceramide production and epidermal density.
4. Improvement of skin structure: Smoothes texture, reduces fine lines and pigment irregularities.
A well-balanced lactic acid peel combines exfoliation with moisture build-up – a significant difference to more aggressive acids.
Studies on lactic acid peels (selection):
– Ditre et al., 1996 (Arch Dermatol): Long-term AHA application led to increased dermis thickness and improved skin firmness.
Smith et al., 1996: 5–12% lactic acid significantly improved epidermal thickness and skin structure.
Green et al., 2009: Evidence of increased ceramide production with topical application.
Van Scott & Yu (pioneering work): Early clinical studies demonstrated effects on xerosis and photoaging.
These data show that a correctly formulated lactic acid peel not only exfoliates but can also bring about a structural improvement in the skin.
Industrial production: Today, production is mainly carried out via:
– Biotechnological fermentation
– Substrate: glucose, molasses, or starch hydrolysates
– Microorganisms: Lactobacillus spp.
– High optical purity (L(+)-form)
– Sustainable, vegan, scalable
– Historical chemical synthesis methods are less relevant today.
L(+)-lactic acid (CAS No. 79-33-4) is also approved as a biocide.
At a concentration of 2% or higher, it has an antimicrobial effect against:
– Bacteria
– Yeasts
– Fungi
– Viruses
Studies confirm its effectiveness against enveloped viruses, including SARS-CoV-2.
The mechanism of action is based on pH reduction and protein denaturation.
Regulatory requirements clearly distinguish between biocide applications and cosmetic claims.
FAQ
Lactic acid in cosmetics: Is a lactic acid peel suitable for sensitive skin?
Yes, in moderate concentrations (2–5%), lactic acid is considered one of the gentler AHAs.
How often should a lactic acid peel be used?
Depending on the concentration, 1–3 times per week or daily at low doses.
Can lactic acid damage the skin barrier?
Yes, if overdosed or if the pH value is too low – that’s why precise formulation is crucial.
Is lactic acid also effective against pigment spots?
Yes, it can reduce hyperpigmentation by accelerating cell renewal.
Is lactic acid vegan?
Yes, modern production is carried out by fermenting plant substrates.
Conclusion on lactic acid peels
If you are looking for new products with lactic acid for your brand, Tojo Cosmetics offers EU-compliant white label products that are immediately available for a quick market entry and already contain this active ingredient.
For individual production orders, Cosactive offers formulation-tested active ingredient mixtures starting from small quantities.
At Cosmacon, we are happy to support you in developing individual products with this innovative active ingredient.