Lactic Acid

Product Information

CosmySupplies supplies Lactic Acid 85% Liquid (INCI: Lactic Acid, CAS: 50-21-5) in India. L-isomer purity minimum 97%. Minimum 85% content. Gentler AHA exfoliant — preferred for sensitive skin, dry skin, and beginners. Use at working concentrations of 0.5 to 10% active lactic acid in toners, serums, and creams. COA available on request. Shipped from Bengaluru across India.

INCI: Lactic Acid  |  CAS: 50-21-5  |  Molecular Formula: C3H6O3  |  Molecular Weight: 90.08  |  EINECS: 200-018-0

L-Isomer Purity: Minimum 97% L-isomer (naturally occurring form) per specification

COSING Functions: Keratolytic | Skin Conditioning Agent | Humectant | pH Adjuster

Used In: Sensitive Skin Toners | AHA Exfoliant Toners | Moisturisers | Serums | Body Lotions | Cleansers | pH Adjustment

Lactic Acid (2-hydroxypropanoic acid) is an alpha hydroxy acid naturally produced by the body during glucose metabolism and found in milk, fermented foods, and various plant sources. In cosmetics it is one of the most versatile and well-studied AHA active ingredients, functioning as a keratolytic exfoliant, humectant, skin conditioning agent, and pH adjuster. Its larger molecular weight compared to glycolic acid (90.08 vs 76.05) means it penetrates the skin more slowly, producing a gentler exfoliant effect at equivalent concentrations — making it the preferred AHA for sensitive skin, dry skin, and first-time AHA users.

Lactic acid is part of the skin's Natural Moisturising Factor (NMF) — the complex of water-soluble compounds in the stratum corneum that maintain skin hydration. This NMF integration gives lactic acid a humectant skin conditioning function that glycolic acid does not have to the same degree, making it particularly suitable for dry and dehydrated skin formulations where AHA exfoliation and hydration need to coexist in the same product.

The L-isomer (L-lactic acid) is the naturally occurring stereochemical form found in the body. The CSW product has minimum 97% L-isomer purity — significantly better than racemic DL-lactic acid mixtures which contain equal amounts of L and D forms. For cosmetic formulation the L-isomer form is preferred for its closer relationship to the skin's own biochemistry.

Benefits

•        L-isomer minimum 97% — cosmetic-grade stereochemical purity: The L-isomer (naturally occurring form) is specified at minimum 97% purity. This differentiates the CSW product from lower-grade DL-racemic lactic acid used in industrial applications. For cosmetic formulation the L-isomer is preferred.

•        Keratolytic exfoliant — gentler than glycolic acid : Lactic Acid is a keratolytic and skin conditioning agent. At equivalent concentrations, lactic acid produces a gentler exfoliant effect than glycolic acid due to its larger molecular weight. This makes it the preferred AHA for sensitive skin toners, dry skin formulations, and first-time AHA users.

•        Humectant function: Lactic acid is a component of the skin's Natural Moisturising Factor. This dual keratolytic plus humectant function is a key commercial differentiator versus glycolic acid, which has lower inherent humectant activity. A lactic acid toner both exfoliates and conditions the skin barrier simultaneously.

•        High-purity specification: Content minimum 85% per specification. Heavy metals NMT 10ppm, Lead NMT 0.5ppm, Arsenic NMT 1ppm, Mercury NMT 1ppm, Cyanide NMT 1ppm.

•        AHA sun advisory compliant : Lactic acid, as an alpha hydroxy acid, increases UV sensitivity. The same AHA sun protection advisory requirement that applies to glycolic acid applies here. Mandatory on all finished products.

•        Water-miscible: Lactic acid 85% liquid is fully water-miscible. Add to the water phase with stirring. No pre-dissolution required. The liquid form enables precise dosing at small batch sizes.

Applications

Sensitive Skin AHA Toner — Primary Application: Add 3.53 to 5.88g per 100g formula for 3 to 5% active lactic acid toner at pH 3.8 to 4.2. Lactic acid is the first AHA toner recommendation for buyers with sensitive skin, dry skin, or no prior AHA experience. The dual exfoliant plus humectant function means a lactic acid toner leaves skin softer and less tight than a glycolic acid toner at equivalent concentrations.

AHA Moisturiser or Body Lotion: At 1 to 5% active lactic acid in a leave-on moisturiser or body lotion, lactic acid provides a gentle cumulative exfoliant effect alongside the humectant skin conditioning function. This is the most commercially accessible combination of exfoliation and moisturisation in a single product. Target pH 5.0 to 5.5.

Exfoliant Serum: At 5 to 10% active lactic acid in a water-based serum at pH 3.8 to 4.5. Suitable for formulators who want a stronger lactic acid serum than a typical sensitive skin toner. Still gentler than a glycolic acid serum at equivalent concentrations.

Body Exfoliant: Lactic acid at 5 to 10% in a body lotion or body wash is one of the most commercially proven applications — keratosis pilaris (KP) body lotions at 5 to 12% lactic acid are a well-established product category. The body skin is generally more tolerant of higher AHA concentrations than the face.

pH Adjuster: At very low addition rates (0.1 to 1%), lactic acid functions as a pH-adjusting ingredient to bring formulation pH to the target cosmetic range (pH 4.5 to 6.5) for water-based products. This is a secondary use alongside the primary exfoliant function.

How to Use

Step 1 — Safety: 85% lactic acid is acidic at concentrate concentration. Wear gloves. Less corrosive than glycolic acid 70% at full concentration (less acute acidity) but still requires appropriate handling precautions. Do not allow undiluted contact with eyes.

Step 2 — Calculate addition rate: Use the dilution table. For a standard 3% active lactic acid toner, add 3.53g per 100g formula.

Step 3 — Add to water phase: Add to the water phase with gentle stirring. Fully miscible — disperses immediately.

Step 4 — Add other water-phase actives: Niacinamide, Hyaluronic Acid, Betaine, Panthenol, or other water-phase actives. Add preservative before pH adjustment.

Step 5 — Adjust pH: Critical step. Measure and adjust to target range. For leave-on sensitive skin toner: pH 3.8 to 4.5. For moisturiser: pH 5.0 to 5.5. Use sodium hydroxide solution (10% in water) to raise pH. Add dropwise. Re-check pH after every addition.

Sun Advisory — Mandatory on Finished Product Labels: AHA sun protection advisory required. Same language as glycolic acid: 'This product contains an AHA that may increase skin sensitivity to the sun. Use sun protection and limit sun exposure while using this product and for one week after discontinuing use.'

Claims You Can Make

For your label and marketing:

AHA Exfoliant | L-Isomer Lactic Acid | Keratolytic | Humectant | Skin Conditioning | Gentle AHA | Sensitive Skin Compatible

For your formulator brief:

Keratolytic | Humectant | Skin Conditioning Agent  | Lactic Acid | CAS 50-21-5 | L-isomer minimum 97% | 85% liquid concentrate | pH-dependent exfoliant activity

For formulation ratios, batch guidance, and troubleshooting support, contact the CosmySupplies team directly.

WhatsApp   |  Email: info@cosmysupplies.com

Technical Information

Pairs Well With

Hyaluronic Acid at 0.1 to 0.5% in the water phase alongside Lactic Acid creates a lactic acid toner with dual exfoliant plus hydration function. The combination is particularly powerful for dry and dehydrated skin toners — lactic acid's inherent humectant function is amplified by HA's water-binding capacity. This is the signature formulation for sensitive and dry skin AHA toner products.

Betaine Powder at 2 to 3% alongside Lactic Acid in a toner reinforces the humectant function with osmolyte-based hydration, creating a three-mechanism hydration and exfoliant toner: lactic acid (keratolytic plus NMF humectant) + HA (humectant) + Betaine (osmolyte). A comprehensive sensitive skin toner active base.

Niacinamide at 3 to 5% in a lactic acid toner formulation at pH 5.0 provides pore-minimising and sebum-regulating function alongside the exfoliant activity. For oily-but-sensitive skin types, a 3% lactic acid plus 5% Niacinamide toner at pH 5.0 is commercially relevant — gentle enough for sensitive skin, active enough for oil control.

Glycolic Acid at a low concentration (1 to 2% active GA) combined with Lactic Acid (2 to 3% active LA) creates a dual-AHA toner where both AHAs contribute complementary exfoliant mechanisms. The combination is more effective for experienced AHA users than either alone at the same total concentration, while remaining more tolerable than a pure glycolic acid toner at the same combined strength.

Allantoin at 0.2 to 0.5% in a lactic acid toner or moisturiser provides soothing and skin conditioning activity that balances the exfoliant function of lactic acid — particularly valuable for sensitive skin formulations where post-exfoliation irritation must be minimised\

Important Information

SUN PROTECTION ADVISORY — MANDATORY ON FINISHED PRODUCT LABEL: Lactic Acid is an alpha hydroxy acid and increases UV sensitivity. Finished products must carry an AHA sun protection advisory.

For formulation use in cosmetic products. Active AHA concentrate — dilute to cosmetic working concentrations before formulation. For external cosmetic use in finished products only. Keep out of reach of children. Store sealed at room temperature away from light.