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Lactic Acid
ORY® product lines:
☑ Skincare
☑ Haircare (scalp exfoliation, pH adjustment, cuticle sealing)
☑ Handmade Soap (as sodium lactate for hardness and humectancy)
☑ Cosmetics (pH adjuster, humectant, mild exfoliating primers) — full dual-use ingredient
Lactic acid is a gentle alpha-hydroxy acid best known from sour milk and fermented foods, and today produced by fermenting sugars. It is a natural component of the skin’s own moisturizing factor (NMF), which makes it uniquely dual-action: at low concentrations it hydrates, and at higher concentrations it exfoliates. A landmark clinical study found that 12% lactic acid increased epidermal and dermal thickness and firmness and reduced fine lines, while 5% improved the epidermis alone [1]. Lactic acid also stimulates ceramide production, strengthening the skin barrier [2]. Its larger molecule penetrates more slowly than glycolic acid, making it the preferred AHA for sensitive and dry skin. It is also one of the most versatile ingredients in the ORY® library: it adjusts pH in shampoos and cosmetics and, when neutralized by lye, becomes sodium lactate, a classic hardener and humectant for handmade soap.
What is Lactic Acid made of?
Lactic acid (C₃H₆O₃, 2-hydroxypropanoic acid) is a naturally occurring AHA. Points to know:
- Source: Produced commercially by bacterial fermentation of sugar (corn, beet, or cane); vegan and biodegradable.
- L-lactic acid: The biologically active isomer, identical to the lactic acid in human skin; ORY® uses the L-form for skin-compatibility [2].
- Part of the natural moisturizing factor: Lactate makes up about 12% of the skin’s NMF, which is why it hydrates as well as exfoliates.
- Sodium lactate: The neutralized salt — a humectant in skincare and a hardening agent in soap.
- Water-soluble liquid: Supplied as an 88–90% aqueous solution.
What skin type is best suited for Lactic Acid?
Lactic acid is the most forgiving AHA and suits all seven ORY® skin types with appropriate concentration:
- Dry: The ideal AHA — exfoliates while boosting hydration and ceramides [2].
- Sensitive: Gentler than glycolic acid; 5% or less buffered with allantoin or Centella.
- Mature: 12% improved firmness, thickness, and fine lines in clinical testing [1].
- Combination: Balances hydration and mild exfoliation across zones.
- Normal: Maintains smooth, radiant skin with weekly use.
- Acne-prone: Reduces surface congestion and post-acne marks; pair with salicylic acid for pores.
- Oily: Smooths texture; choose a light gel base.
What hair type is best suited for Lactic Acid?
Lactic acid is one of the most commonly used acids in professional haircare — as a pH adjuster, a scalp exfoliant, and a cuticle-sealing agent:
- Dry or damaged: Low-pH lactic treatments close the cuticle, reducing porosity and improving softness.
- Color-treated or chemically processed: Acidic rinses help re-seal the cuticle and prolong color.
- Curly and coily: Gentle scalp exfoliation and pH balancing that respects moisture needs.
- Dandruff-prone scalp: Loosens flakes and buildup more gently than glycolic acid.
- Sensitive scalp: The preferred scalp acid for reactive scalps at 1–2%.
- Oily scalp: Clarifies buildup and balances scalp pH.
- Straight, wavy, mature or thinning: pH adjustment and shine in shampoos and rinses.
What are the benefits of Lactic Acid?
Lactic acid combines exfoliation with genuine skin-barrier benefits [1, 2, 3, 4]:
- Gentle exfoliation: Loosens dead cells for smoother, brighter skin with less sting than glycolic acid.
- Hydration: A humectant and NMF component that draws water into the stratum corneum [4].
- Barrier strengthening: Stimulates ceramide synthesis, reducing water loss and improving resistance to irritants [2].
- Anti-aging: Increases dermal thickness and firmness and reduces fine lines at 12% [1].
- Brightening: Speeds turnover to fade hyperpigmentation and post-acne marks.
- Rough-skin smoothing: Effective for keratosis pilaris, rough elbows, heels, and body skin.
- Haircare functions: Adjusts formula pH, seals the cuticle for shine, and exfoliates the scalp.
- Soap functions: As sodium lactate, hardens bars, speeds unmolding, and adds humectancy.
Dual use across ORY® product lines
Lactic acid is the rare exfoliating acid that finds a genuine role in every ORY® line — although in soap it acts through its neutralized salt rather than as an exfoliant.
Pros and cons of Lactic Acid
Pros
Cons
- Gentle yet effective: The best AHA for sensitive and dry skin.
- Hydrates while exfoliating: Unique among exfoliants because it is part of the skin’s NMF.
- Barrier-positive: Boosts ceramides rather than depleting them [2].
- Four-line utility: Exfoliant, pH adjuster, humectant, and soap hardener.
- Natural, vegan, affordable: Fermentation-derived commodity ingredient.
- Slower results than glycolic: Larger molecule penetrates more gradually.
- Photosensitivity: Still an AHA; daily sunscreen is required.
- pH-dependent: Must stay at pH ≥3.5 in leave-ons for CIR safety [3].
- Stinging at high concentration: Above 10% can tingle, especially on compromised skin.
- Lye calculation in soap: Requires precise formulation to avoid a lye-heavy or superfatted bar.
What is the best application of Lactic Acid?
Lactic acid is typically applied at night and layered under moisturizer:
- Exfoliating toner: 5% liquid, 2–3 nights weekly to start.
- Serum: 8–12% for firmness, brightening, and fine lines.
- Body lotion: 10–12% for keratosis pilaris, rough arms, legs, and feet.
- Cleanser: Gentle daily exfoliation with limited contact time.
- Peel mask: Weekly rinse-off treatment for dull skin.
- Scalp serum: 1–3% before shampooing, once or twice weekly.
- Acid hair rinse: 1–2% rinse (pH 3.5–4) after conditioner to seal the cuticle.
- Soap: Sodium lactate for a harder, smoother bar — customers see the benefit as a longer-lasting soap.
- Pairing: Layer with hyaluronic acid, niacinamide, or Centella; alternate nights with retinol; SPF 30+ daily.
Peer-reviewed references
- Smith WP. Epidermal and dermal effects of topical lactic acid. Journal of the American Academy of Dermatology. 1996;35(3 Pt 1):388–391.
- Rawlings AV, Davies A, Carlomusto M, et al. Effect of lactic acid isomers on keratinocyte ceramide synthesis, stratum corneum lipid levels and stratum corneum barrier function. Archives of Dermatological Research. 1996;288(7):383–390.
- Andersen FA (Cosmetic Ingredient Review Expert Panel). Final report on the safety assessment of glycolic acid … and lactic acid, ammonium, calcium, potassium, sodium, and TEA-lactates … International Journal of Toxicology. 1998;17(Suppl 1):1–241.
- Algiert-Zielińska B, Mucha P, Rotsztejn H. Lactic and lactobionic acids as typically moisturizing compounds. International Journal of Dermatology. 2019;58(3):374–379.
- Tang SC, Yang JH. Dual effects of alpha-hydroxy acids on the skin. Molecules. 2018;23(4):863.
Disclaimer:
The information on this page is provided by ORY International, LC for educational purposes only. It summarizes published research about lactic acid as an ingredient, including laboratory and animal studies and clinical studies of formulas that may differ from ORY® products. Results from these studies may not apply to every person or to ORY® products. This page is not medical advice and does not replace advice from a dermatologist, physician, or other qualified healthcare provider.
ORY® Skincare, Haircare, Handmade Soap, and Cosmetics products are cosmetics. They are not intended to diagnose, treat, cure, mitigate, or prevent any disease or condition, including keratosis pilaris, ichthyosis, acne, melasma, sun damage, dandruff, or hair loss. References to FDA or Cosmetic Ingredient Review (CIR) findings describe the ingredient, not ORY® products, and do not mean FDA has reviewed or approved any ORY® product.
Sunburn Alert (for exfoliating products): This product contains an alpha hydroxy acid (AHA) that may increase your skin’s sensitivity to the sun and particularly the possibility of sunburn. Use a sunscreen, wear protective clothing, and limit sun exposure while using this product and for a week afterwards.
Results vary by skin and scalp type, formulation, and use. Lactic acid can tingle or sting at higher strengths, especially on compromised skin, and any cosmetic can cause irritation, sometimes from other ingredients. Always patch test, follow label directions, and stop use if irritation occurs. If you are pregnant, nursing, have a medical condition, or are buying for a child, consult a healthcare provider before use.
ORY International, LC works to keep this page accurate and current but makes no warranty as to its completeness. To the fullest extent permitted by law, ORY International, LC is not liable for any loss or injury arising from reliance on this information or from use of any product contrary to its label directions. To report a reaction, contact us at [insert contact email / phone].
