pH controlAt a traceIn every formula

Lactic Acid

Lactic Acid · INCI Lactic Acid

Lactic acid is one of the best known ingredients in skincare. It is an alpha hydroxy acid, and at the right strength it loosens dead cells and smooths the surface of the skin. Our products contain roughly one part in fifty thousand of it, which is nowhere near enough to do any of that. So why is it on the label at all?

It is a famous exfoliating acid. Ours is present at about one part in fifty thousand, and it is not exfoliating you. Here is what it is actually doing.

Lactic acid, present at a trace to hold the chlorella active at the right acidity.

What it is

The answer is unglamorous, which is rather the point. Our chlorella active is supplied as a liquid, and that liquid has to be held at a particular acidity or the algal compounds in it are not stable. A small amount of lactic acid is what holds it there. Its maker lists the function in one phrase: pH modifier. It makes up a fraction of a percent of that active, and the active makes up one percent of our formula. Multiply the two together and you get about two thousandths of one percent.

At that level it is not doing anything to your skin. It is not exfoliating, not smoothing, not brightening. It finished its work before the ingredient ever reached our workshop, inside the bottle it arrived in. It is on our label because everything is on our label, including the parts that are not working for you.

What it does in our formulas

One thing, and it is not the thing you would expect.

It holds the chlorella at the right acidity

That is the whole job, and its maker names the function plainly: pH modifier. Our chlorella active is a liquid that has to sit at a particular acidity for the algal compounds in it to stay stable, and a small amount of lactic acid is what holds it there. It did its work inside that bottle, before the active ever reached us.

Well characterised

What the research does not show

This page exists because of one of the quieter tricks of the industry, and lactic acid is the ideal place to explain it.

Marketed as An exfoliating AHA that resurfaces the skin

It is one, at the right dose. Products that exfoliate with lactic acid use it at five to ten percent or more. Ours contains roughly two thousandths of one percent, because it arrives as a trace inside another ingredient. It is doing nothing to the surface of your skin. If we had wanted an exfoliating acid, we would have added one and told you so.

Marketed as Proof that a product contains actives

Here is the trick worth knowing. A brand can put a famous ingredient on a label at a level far too low to do anything at all, and simply let you assume. The ingredient list will never give it away, because ingredient lists do not carry percentages. Ours do, on every product page. That is the only way you could ever check, which is precisely why we publish them.

So no, our products do not exfoliate, and the lactic acid on the label is not evidence that they do. It is evidence that we list everything. Those are two very different things, and we would rather you knew which one you were looking at.

On the label and in the range

Lactic acid is the last ingredient on every one of our lists, which is exactly where a trace belongs. Ingredient lists are ordered by how much of each thing is in the product, so the bottom of the list is the honest place to look for what is barely there. The exact percentage is published on each product page, as it is for everything we use.

Is it suitable for me?

Lactic acid is made by fermenting plant sugars, suits a vegan routine, and carries no restrictions at this level under UK or EU cosmetic law. At around two thousandths of a percent it presents no irritation concern of any kind, including for sensitive skin. The research shows lactic acid is well tolerated even at the far higher levels used in exfoliating products, and ours is nowhere near those.

Vegan-friendlySensitive-skin suitableNo known safety concerns

As with anything new, if your skin reacts easily it is worth patch testing first.

The research behind this page

We review the published literature. We do not conduct the studies below.

Green BA, Yu RJ, Van Scott EJ. Clinical and cosmeceutical uses of hydroxyacids. Clin Dermatol 2009;27(5):495-501. →
ALGAKTIV S.L. (Barcelona). ALGAKTIV BioSKN Product Information Dossier, v2024.0, and technical efficacy dossier. Manufacturer data, unpublished. Sponsor-generated. →

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