The Ordinary Lactic Acid 10% + HA Review

Of the five acids The Ordinary sells in a 30 mL dropper bottle, this is the one people are most often told to start with, and the one whose product page contains the most useful information. It is a 10% lactic acid with the acid sitting second on a fifteen-item ingredient list, at a published pH of 3.60 to 3.80 — and, unusually, the brand publishes why it chose that pH. That single paragraph is the reason this review is worth writing.

A word on what this review is. We have not used this product and we do not review by using things — no lab, no panel, no “I tried it for six weeks.” What we did instead is fetch and read the brand’s own product page for the complete ingredient list, the stated pH band, the directions and the claim badges, then set that against the published consumer-safety limits for alpha hydroxy acids and against what the AHA trial base actually tested. Every source is linked below; the method is in how we pick. What you get is a review of what is in the bottle and who should buy something else. What you do not get is a description of how it felt on our face.

The verdict in one paragraph

Buy it if your skin is dry or normal, your complaint is rough or dull surface texture rather than a specific mark or a breakout, and you have used a leave-on acid before without drama. It is honest, cheap, and better documented than almost anything at this price: a printed 10%, the acid second on the list behind only water, a published pH band, a stated anti-irritant extract, and no fragrance in the formula. Buy the mandelic instead if your skin is reactive or this is your first acid, and buy the glycolic toner instead if you need volume or your skin is resilient and you want faster penetration. Do not buy itif your skin is currently sensitive, peeling or compromised — that is not our caution, it is printed in the brand’s own directions.

At a glance

The Ordinary Lactic Acid 10% + HA

Stated active: 10% lactic acid. Ingredients: 15, no fragrance in the list. Brand-stated pH:3.60–3.80 (“approximately 3.8” in the brand’s own copy).

Sizes: one 30 mL size. A 5% version of the same formula is sold alongside it.

$9.20 · View on Amazon

Price as of October 10, 2026. #ad How we’re funded

Product image supplied by Amazon.

What is on the label

The complete ingredient list, from the brand’s page, in order:

Aqua (Water), Lactic Acid, Glycerin, Pentylene Glycol, Propanediol, Sodium Hydroxide, Sodium Hyaluronate Crosspolymer, Tasmannia Lanceolata Fruit/Leaf Extract, Acacia Senegal Gum, Xanthan Gum, Isoceteth-20, Trisodium Ethylenediamine Disuccinate, Ethylhexylglycerin, 1,2-Hexanediol, Caprylyl Glycol.

Fifteen items, and the shape of the list tells you most of what you need. The acid is second, behind only water — the same position it occupies on the glycolic toner, and the opposite of the situation on Paula’s Choice 2% BHA, where the salicylic acid sits fourth behind two solvents whose job is to dissolve it. Third place goes to glycerin, a humectant, which is a real and often-overlooked detail: there is something in this formula actively holding water in the skin while the acid works, which is exactly what you want in a product aimed at dry skin.

Sodium hydroxide at sixth is the pH adjuster — it is what buffers a 10% acid up to 3.8 rather than leaving it at whatever a 10% lactic solution would naturally sit at. The “+ HA” in the name is sodium hyaluronate crosspolymer, seventh; a crosslinked hyaluronic acid rather than the plain sodium hyaluronate on most hydrating serums. If the naming conventions confuse you, hyaluronic acid vs sodium hyaluronate is the explainer.

Eighth is Tasmannia lanceolatafruit and leaf extract — Tasmanian pepperberry, which the brand describes on the page as “a known anti-irritant.” It is the same extract that sits in the glycolic toner, and on that product the brand warns it can cause seasonal color variation in the formula. Treat “known anti-irritant” as a brand characterization rather than a trial result; we have not found a published trial of this extract against AHA stinging, and we are not going to imply one exists.

The rest is housekeeping: two gums for texture, a solubiliser, a chelator and the preservative system. Nothing in the list is a fragrance, an alcohol, an oil or a silicone, which matches the brand’s published highlights — alcohol-free, oil-free, silicone-free, vegan, gluten-free, cruelty-free. Note what is not on that list: fragrance-free. No fragrance appears in the formula and the brand still does not make the claim, exactly as on its glycolic and salicylic products. We report the absence rather than filling it in.

The pKa argument, and whether it holds up

Here is the sentence that makes this page worth reading, quoted from the brand’s own product page:

“The pH of this formula is approximately 3.8. Lactic Acid has a pKa of 3.8 and pKa is the most important aspect to consider in formulating with acids. pKa implies acid availability. When pKa is close to pH, there is an optimal balance between salt and acidity, optimizing the delivery of the acid form to ensure it provides an effective exfoliation that can be used daily.”

That is a real formulation principle, stated correctly, and it is almost unheard of on a consumer product page. The short version: a weak acid in water exists partly as the free acid and partly as its salt, and the proportion depends on how the formula’s pH compares with the acid’s pKa. The free-acid form is the exfoliating form. At a pH equal to the pKa you have roughly half and half; push the pH down and you get more free acid and more sting, push it up and you get less of both. Formulating at pH ≈ pKa is the deliberate middle: meaningful activity without the harshness of a lower-pH formula.

Two honest qualifications. First, “the most important aspect” is the brand’s emphasis, not a consensus position — concentration, vehicle and contact time all matter too. Second, and more usefully: this argument is the reason the number on this bottle is not directly comparable to the number on another. A 10% at pH 3.8 is a different exposure from a 10% at pH 3.2, and a 7% at pH 3.6 sits somewhere else again. Reading percentages across brands as if they were a single scale is the most common mistake in this category, and the pKa paragraph is the clearest explanation of why that is wrong that you will find on a product page.

For context on where a 10% leave-on AHA sits in regulatory terms: the 2024 review of AHAs in dermatological practice sets out the 2005 US FDA guidance of no more than 10% AHA at pH 3.5 or higher for over-the-counter use, with sun protection formulated in or instructed on the label. This product is at the top of that band and inside it. The same review notes the EU scientific committee’s far more conservative recommendation — glycolic acid up to 4% at pH of at least 3.8 — so a European reader should know this is a US-limit product.

What lactic acid at this strength is and is not evidenced to do

The thing worth internalising about AHA evidence is how much of it is peel data. The 2024 review describes three practical tiers: up to about 10% for daily home use above pH 3.5, under 30% for trained professionals near pH 3, and drug territory beyond that. Almost every efficacy trial it reviews sits in the second or third tier — professional peels at 20% to 70% — and it says plainly that “the optimal concentrations for therapeutic efficacy with minimal side effects are yet to be precisely defined.”

So the honest claim for this bottle is the modest one: it is a home-use exfoliant at the top of the consumer band, and the surface effects people buy it for — smoother feel, less visible dullness, better light reflection — are what the mechanism supports. What it is not is a small peel. If you want the deeper effects described in the peel literature, the product you need is administered by someone else.

Where lactic acid has a specific advantage worth paying for: it is one of the AHAs the AAD names for exfoliating keratosis pilaris, and its larger molecule penetrates more slowly than glycolic’s, which is the mechanistic basis for the widely-held view that it suits dry and easily-irritated skin better. That comparison is set out properly in lactic acid vs glycolic acid.

The three The Ordinary AHAs, on their own labels

These three products are routinely recommended interchangeably and their labels are genuinely different. Everything in this table is read from the brand’s own pages.

The row that should change a purchase is the last-but-one. Lactic acid is the only one of the three sold at a lower strength, which means it is the only one of the three you can start on properly. If you are new to acids and set on this range, the 5% is the honest first bottle and the 10% is the upgrade.

Price, size and the 30 mL problem

One 30 mL size, which is the standard for this range and the single biggest practical limitation of the product. At two or three evenings a week on a face, a 30 mL dropper bottle is a sensible few months. Used on anything larger — neck and chest, backs of the arms, legs — it is gone almost immediately, and that is the whole reason our body exfoliant roundup excludes it. Lactic acid is a legitimate ingredient for body texture; this bottle is not the way to buy it.

The price on the button above is Amazon’s live price, refreshed daily and stamped with the date we read it, rather than a number we typed in once. We have no incentive to steer you to one listing over another.

How to use it

The brand’s direction is once daily, ideally in the evening. We would start lower: two or three evenings a week, after cleansing, before moisturizer, on dry skin. Build up only once a fortnight has passed without tightness or stinging, and never stack it with another acid or a retinoid on the same night — how to layer actives has the schedule and the conflict matrix.

One genuinely useful instruction from the brand that most people miss: “The formula can be diluted with other products to reduce strength until skin develops tolerance.” Mixing a few drops into your moisturizer for the first fortnight is a legitimate way to ease into a 10% acid, and it is the brand telling you so, not us improvising.

Two prohibitions. “Do not use on sensitive, peeling, or compromised skin” is on the label and it is the most-ignored sentence on any acid bottle — if you are already flaking, this is the thing making it worse, not the thing that fixes it. And the FDA-recommended AHA Sunburn Alert on the label is not decoration: an AHA can increase sun sensitivity and the possibility of sunburn, so daily broad-spectrum sunscreen comes with the purchase. If you see the tells in signs of over-exfoliation, stop entirely for a week rather than reducing frequency.

Who should buy something else

Reactive or genuinely sensitive skin: the mandelic acid at the same strength, for the molecular-weight reason the brand itself gives, or the 5% lactic. Our sensitive-skin exfoliant roundup ranks the whole field on tolerability.

Blackheads, congestion or breakouts:an AHA is the wrong class. Salicylic acid is oil-soluble and gets into the pore, which is where the problem is — best salicylic acid.

Dark marks and uneven tone as the main complaint: exfoliation helps at the margins, but azelaic acid and vitamin C are the better-targeted tools. Best azelaic acid and best vitamin C serum for dark spots are the places to start.

Body texture or keratosis pilaris: right ingredient, wrong bottle size. Buy volume.

Bottom line

This is one of the best-documented cheap actives on the market, and the documentation is the reason to buy it: a printed 10%, the acid second on a fifteen-item list, a published pH band, glycerin high in the formula, and a brand that explains its pH choice in terms of the acid’s pKa rather than asserting that it is “optimized.” For dry or normal skin with a surface-texture complaint, it is an easy recommendation. Start at two or three nights a week rather than the daily use the label permits, dilute it into a moisturizer for the first fortnight if you are unsure, wear sunscreen, and buy the 5% instead if you have never used an acid before. If your skin is currently irritated, the right move is to buy nothing at all for a week.