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Moumoujus

LACTIC ACID.

Essential CAS 50-21-5 / BUFFERING, HUMECTANT, SKIN CONDITIONING

Lactic Acid, an alpha-hydroxy acid (AHA), is a multifaceted ingredient renowned for its ability to gently exfoliate the skin's surface while simultaneously providing significant hydration. It effectively improves skin texture, tone, and clarity, making it a valuable asset in addressing concerns ranging from fine lines and wrinkles to hyperpigmentation and acne.

Summary

Exfoliant Moisturizer / Humectant Buffering Skin Brightening Anti-aging Acne Treatment Collagen Production Booster Antibacterial

Science

Mechanism of Action

Lactic Acid functions primarily as an exfoliant by chemically breaking the bonds between dead skin cells in the stratum corneum, facilitating their detachment and promoting cellular turnover. Beyond exfoliation, it acts as a humectant, drawing and retaining moisture within the skin, thereby enhancing its Natural Moisturizing Factor (NMF). It actively improves skin tone and texture by inhibiting melanogenesis, accelerating epidermal renewal to fade dark spots, and promoting a brighter complexion. For anti-aging, it encourages collagen production and, at concentrations of 10% and higher, increases skin firmness and thickness, diminishing the appearance of fine lines and wrinkles. Furthermore, Lactic Acid exhibits antibacterial properties, targeting acne-causing bacteria by compromising their cell membranes.

Research

Clinical Evidence

High confidence
Effective range 1–92%
Optimal

10%

Key findings

  1. 01 Significantly improved skin texture and reduced up to 90% of inflammatory lesions in individuals with acne.
  2. 02 Delivers superficial effects including a brighter, smoother complexion, faded age spots, and reduced wrinkles and visible pores. No impact on the middle layer of skin was observed.
  3. 03 Effectively removes the top layer of dead skin cells, enhances skin texture, lightens dark spots, smooths fine lines, and cleanses pores.
  4. 04 Promotes significant improvements in skin firmness, thickness, and a reduction in the appearance of wrinkles. At 12%, it deeply hydrates skin, can permeate into deeper layers, and is shown to be highly effective for ichthyosis treatment (moisturizing, exfoliation) and, when combined with 0.05% tretinoin, significantly improves Acanthosis nigricans symptoms.
  5. 05 Used in superficial chemical peels to remove the top layer of dead skin cells.
  6. 06 Demonstrated superior efficacy and safety in professional melasma treatments compared to glycolic acid. Specifically, 60% Lactic Acid achieved an 80.4% effective rate, and 92% resulted in fewer side effects than 50% glycolic acid peels.

Transparency

Dusting Analysis

Not commonly dusted

Lactic Acid is a well-researched active ingredient with established efficacy thresholds spanning various concentrations for specific benefits. Its inclusion in cosmetic formulations is typically to achieve distinct functional outcomes, making 'dusting' at sub-effective levels for marketing purposes uncommon.

The Formula

Formulation

Solubility
Water
Optimal pH 3 – 4
0 7 14

Stability

For safe and effective topical application, pure Lactic Acid, which is highly corrosive and unstable, must be carefully formulated, diluted, and pH buffered. Optimal exfoliation without compromising the skin barrier is typically achieved at a pH range of 3.0 to 4.0. The L-lactic acid isomer is the preferred form in cosmetic products due to its generally milder effects and reduced irritation potential compared to D-lactic acid.

Safety

Safety Profile

CIR Status
Safe with restrictions
Max tested
10%
Sensitization risk Moderate

The US Cosmetic Ingredient Review (CIR) Expert Panel deems Lactic Acid safe for consumer topical cosmetic products at concentrations up to 10% and a pH of 3.5 or greater, provided sun sensitivity warnings and daily sun protection directions are included. For professional salon use, concentrations up to 30% are considered safe at a pH of 3.0 or greater, for brief, discontinuous use with thorough rinsing and professional application. The FDA also lists Lactic Acid as Generally Recognized As Safe (GRAS) as a direct food additive and considers cosmetic products with ≤10% Lactic Acid at pH ≥3.5 safe with sun protection measures. The European SCCS concluded safety at ≤2.5% and pH ≥5, based on precautionary principles, noting increased UV damage from AHA application. Health Canada includes Lactic Acid on its Cosmetic Ingredient Hotlist under AHAs, emphasizing the necessity of daily sun protection due to increased skin sensitivity to the sun.

Your Skin

Skin Compatibility

Yes Normal
Yes Dry
Yes Oily
Yes Sensitive
Irritancy Low
Comedogenicity Low

Our Assessment

Verdict

Essential

Lactic Acid is an exceptionally versatile and highly effective AHA, offering significant benefits in exfoliation, hydration, skin brightening, anti-aging, and acne management across a wide range of concentrations suitable for diverse skincare needs.

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