Lactic Acid 10% + HA

The history of lactic acid in skincare stretches back further than any other chemical exfoliant — all the way to ancient Egypt, where Cleopatra reportedly bathed in sour milk for softer, more luminous skin. She was, without knowing the chemistry, using lactic acid. The molecule formed during milk fermentation is the same one in this frosted glass bottle, and the mechanism — dissolving bonds between dead skin cells to reveal fresher skin beneath — hasn't changed in two thousand years. What has changed is the delivery.

The Ordinary's Lactic Acid 10% + HA takes this ancient ingredient and wraps it in a formula designed with a specific user in mind: the person whose skin needs exfoliation but can't tolerate the aggressive drying that glycolic acid often brings. This distinction matters more than it might seem. Glycolic acid, the smallest and most popular AHA, penetrates deeply and exfoliates aggressively — excellent for resilient, oily skin, but potentially punishing for anyone prone to dryness. Lactic acid is a larger molecule. It works primarily at the skin's surface, dissolving dead corneocytes without reaching the depths where glycolic acid can trigger inflammation in reactive skin. And crucially, lactic acid has a property that glycolic acid lacks entirely: it functions as a humectant, actively drawing moisture into the skin while it exfoliates.

This dual action — exfoliation plus hydration — is what makes this formula genuinely different from the dozens of AHA products on the market. The Ordinary amplifies the hydrating angle with glycerin listed third in the INCI (an unusually prominent position indicating a meaningful concentration) and a sodium hyaluronate crosspolymer that provides sustained water-binding capacity. The result is a three-layered hydration system operating concurrently with the exfoliation: lactic acid draws moisture in, glycerin holds it at the surface, and the HA crosspolymer provides sustained hydration that outlasts the standard humectant effect. You're not choosing between exfoliating your skin and hydrating it — you're doing both in the same step.

The inclusion of Tasmannia Lanceolata extract — The Ordinary's signature sensory modifier — reduces the stinging that even lactic acid can cause at 10% concentration and a pH of 3.6-3.8. The Tasmanian Pepperberry derivative modulates TRPV1 pain receptors, diminishing the burning sensation without altering the acid's activity. Multiple reviewers specifically note that this product doesn't sting even on slightly reactive skin, which suggests the Pepperberry extract is doing meaningful work.

The texture is a pleasant surprise for an acid product — a lightweight, slightly viscous serum that applies smoothly and absorbs without leaving the heavy, tacky residue that some AHA products inflict. There's a faint acidic note if you bring the bottle to your nose, but nothing perceptible once it's on the skin. On application, there's a mild tingling that fades within a minute — noticeable enough to know something is happening, mild enough that it never crosses into discomfort for most users.

Results follow the standard AHA timeline, but with a distinctly dry-skin-friendly profile. Immediate brightening after the first use — that fresh, luminous look that comes from removing the dullest surface layer. Within one to two weeks, skin tone becomes noticeably more even and texture smooths out. The four-to-eight-week mark is where the deeper benefits emerge: faded dark spots, improved post-inflammatory hyperpigmentation, and a cumulative luminosity that makes the skin look genuinely healthier. Throughout all of this, the skin doesn't go through the desert-dry phase that glycolic acid users often endure. The built-in hydration system means your moisture barrier isn't sacrificed for exfoliation.

The formula's limitations are straightforward. At 10% lactic acid with a pH near 3.7, this is not for sensitive skin — the Pepperberry extract reduces irritation but doesn't eliminate it, and genuinely reactive skin will still protest. Many users find daily application too frequent, settling into a 3-4 times per week rhythm that delivers results without overtaxing the skin. Sunscreen compliance is non-negotiable, as with any AHA product. And the 30ml bottle, while standard for The Ordinary's serum range, feels small for a product you might also want to use on your body.

At $9.20, the value calculation is simple and decisive. A 10% lactic acid serum with hyaluronic acid crosspolymer, meaningful glycerin concentration, and Tasmannia Lanceolata sensory modification — for less than the price of a sandwich. The formulation would be competitive at five times the price. At this price, it's a no-brainer for anyone whose exfoliation needs come with a side of dryness.

The Ordinary's Lactic Acid 10% + HA isn't trying to replace glycolic acid — it's offering a different path to the same destination for people who need one. Smoother, brighter, more even skin without the moisture tax. Cleopatra would approve, though she'd probably be annoyed about the price.

Formula

The Science

Lactic acid belongs to the alpha-hydroxy acid family but differs from glycolic acid in molecular size and mechanism. With a molecular weight of 90.08 g/mol (compared to glycolic acid's 76.03 g/mol), lactic acid penetrates more slowly and acts primarily at the stratum corneum surface. This is not a disadvantage — for surface-level concerns like dullness, texture, and mild hyperpigmentation, superficial exfoliation is precisely what's needed, with less risk of deep-layer irritation.

At pH 3.6-3.8, this formula sits near lactic acid's pKa of 3.86 — the pH at which exactly 50% of the acid exists in its free (protonated) form. This means roughly half the lactic acid is in its active, penetrating form at any given time. This is a deliberate formulation choice: enough free acid for meaningful exfoliation, but not so much that the product overwhelms the skin's buffering capacity.

What makes lactic acid biochemically unique among AHAs is its role as a natural moisturizing factor (NMF) component. Lactic acid and its salt, sodium lactate, are naturally present in the stratum corneum as part of the NMF — the collection of hygroscopic molecules that maintain skin hydration. A study published in the Journal of the American Academy of Dermatology by Smith (1996) demonstrated that topical lactic acid at cosmetic concentrations increases ceramide synthesis in the stratum corneum, directly strengthening the moisture barrier while exfoliating. This dual mechanism — exfoliation plus barrier enhancement — is unique to lactic acid and not shared by glycolic acid.

The Tasmannia Lanceolata extract functions through its polygodial content, which acts as a TRPV1 receptor modulator. These are the same receptors activated by capsaicin and low-pH acid contact. By desensitizing these receptors, the extract reduces the subjective experience of stinging and burning without altering the acid's pharmacological activity — the exfoliation continues unimpeded while the perceived irritation diminishes.

References

1. Glycolic acid peel therapy – a current review — Clinical, Cosmetic and Investigational Dermatology (2013)

Dermatologist Perspective

Dermatologists frequently recommend lactic acid as the preferred AHA for patients with dry or mildly sensitive skin who need chemical exfoliation. Board-certified dermatologists note that lactic acid's larger molecular size produces a more superficial exfoliation than glycolic acid, reducing the risk of post-inflammatory hyperpigmentation — particularly relevant for darker skin tones. The molecule's dual function as both exfoliant and humectant is widely cited in dermatological literature as a distinguishing advantage. This specific formulation is often recommended as a starting point for patients transitioning from physical to chemical exfoliation, with the Tasmannia Lanceolata extract providing an additional tolerance advantage that many dermatologists appreciate in patient-directed products.

Guidance

Lactic acid has a fascinating origin story in skincare — it was used by Cleopatra in the form of sour milk baths, making it arguably the oldest chemical exfoliant in human history. The Ordinary's formulation modernizes this ancient ingredient with contemporary delivery technology, including the Tasmannia Lanceolata anti-irritant that makes a 10% concentration feasible for daily use. The product was part of The Ordinary's original 2017 lineup and has remained one of the brand's top sellers, particularly among users who found glycolic acid too aggressive.

About The Ordinary Established Brand (5–20 years)

The Ordinary launched in 2016 under parent company DECIEM and quickly became one of the most recognized names in affordable, ingredient-focused skincare. While the brand lacks proprietary clinical trials on its specific formulations, it builds products around well-studied actives at transparent concentrations, earning widespread dermatologist acknowledgment.

Brand founded: 2016 · Product launched: 2017

Myth vs. Reality

Myth

Lactic acid is weaker than glycolic acid and therefore less effective.

Reality

Lactic acid is a larger molecule that exfoliates at the surface rather than penetrating as deeply as glycolic acid. This isn't weakness — it's a different mechanism. For surface-level concerns like dullness, texture, and mild hyperpigmentation, lactic acid is equally effective with less irritation risk. Its added humectant properties make it superior for dry skin types.

Myth

You need to wash off a lactic acid serum after a certain time.

Reality

This is a leave-on treatment, not a wash-off peel. The pH and concentration are formulated for extended skin contact. Apply, let it absorb, and proceed with the rest of your routine. Only higher-concentration lactic acid peels (20%+) require timed removal.

FAQ

Common Praise

"Effectively clears blackheads and congestion without excessive dryness"

"Gentler than glycolic acid with comparable exfoliation results"

"Doesn't sting even on slightly reactive skin thanks to the Pepperberry extract"

"Visible improvement in skin texture and brightness within weeks"

"Excellent value at under $10 for a well-formulated AHA serum"

Common Complaints

"Too strong for some users to use daily — many limit use to 1-2 times per week"

"Requires strict sunscreen compliance due to increased photosensitivity"

"Small 30ml bottle size with no larger option available"

"Can cause purging during the first 1-2 weeks in congested skin"

Notable Endorsements

Frequently recommended by dermatologists as a gentler AHA alternative to glycolic acid for dry skin typesFeatured in multiple best chemical exfoliant roundups

Appears In

best exfoliant for dryness best exfoliant for dullness best exfoliant for hyperpigmentation best gentle aha exfoliant best exfoliant for dark spots

Related Conditions

dullness texture hyperpigmentation dryness dark spots aging sun damage

Related Ingredients

lactic acid aha hyaluronic acid tasmannia lanceolata glycerin