Quick Comparison
| Lactic Acid | Squalane | |
|---|---|---|
| Typical Concentration | Concentrations: 5-12% for daily use. 30-50% for professional peels. Start with 5% every other night. The Ordinary offers 5% (gentle) and 10% (moderate) options. Always use SPF during the day. | Can be used pure (100% squalane oil) or in formulations. Apply 2-3 drops after water-based products. Can be mixed with moisturizer. Safe for morning and night use. Non-comedogenic rating: 0-1 (very unlikely to clog pores). |
| Application | Topical (serum, peel, toner). Apply to dry skin at night. Follow with moisturizer. | Topical (oil, serum, cream ingredient). Apply as the last step of skincare (after water-based products) or mix into moisturizer. |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
Lactic Acid
Lactic acid (90 Da, larger than glycolic acid) exfoliates via the standard AHA mechanism: chelating calcium at corneodesmosomes and promoting desquamation through protease activation. Unlike glycolic acid, lactic acid is a natural component of the skin's natural moisturizing factor (NMF) and functions as a humectant, drawing water into the stratum corneum through hygroscopic binding. It inhibits tyrosinase enzyme activity in melanocytes, providing mild brightening. At higher concentrations (10%+), lactic acid upregulates serine palmitoyltransferase and glucosylceramide synthase in keratinocytes, stimulating ceramide synthesis and improving barrier lipid composition. It also enhances filaggrin proteolysis to NMF components. This dual action—exfoliation plus barrier support—makes it the most moisturizing AHA and clinically useful for dry, sensitive, or barrier-compromised skin.
Squalane
Squalane is the fully hydrogenated form of squalene—a C30 isoprenoid hydrocarbon. As a saturated branched-chain hydrocarbon, squalane forms a non-occlusive emollient film that fills intercellular lipid spaces and reduces transepidermal water loss (TEWL) by approximately 20-30%. Squalene comprises ~12% of human sebum (synthesized via mevalonate pathway); squalane's structural similarity confers high biocompatibility and minimal comedogenic potential. Hydrogenation of squalene's six double bonds eliminates oxidative susceptibility—squalene peroxidizes with UV exposure while squalane remains stable. Squalane penetrates the stratum corneum and may support barrier lipid organization. Plant-derived squalane (sugarcane, olive) is structurally identical.
Risks & Safety
Lactic Acid
Common
Mild stinging, redness — less than glycolic acid at equivalent concentrations. Sun sensitivity.
Serious
None at cosmetic concentrations.
Rare
Over-exfoliation with daily high-concentration use.
Squalane
Common
Essentially none. May cause breakouts in a small percentage of people despite low comedogenic rating.
Serious
None.
Rare
Allergic reaction is extremely rare.
Full Profiles
Lactic Acid →
A gentle AHA derived from milk that provides chemical exfoliation plus hydration — a unique dual benefit. Lactic acid has a larger molecular size than glycolic acid, so it penetrates more slowly and causes less irritation, making it ideal for sensitive skin and AHA beginners. It also has humectant properties, drawing moisture into the skin as it exfoliates.
Squalane →
A lightweight, non-comedogenic emollient oil derived from squalene — a lipid naturally produced by human sebaceous glands. Squalane (the hydrogenated, stable form) mimics the skin's natural oils, making it an excellent moisturizer that rarely causes breakouts. It softens skin, reduces water loss, and has antioxidant properties. Increasingly sourced from sugarcane and olives rather than shark liver.