Ingredient

Glycolic acid

Evidence grade: Grade BNot suggested by us, for these reasons

On an ingredient list as: Glycolic Acid

Also called: aha

Would we suggest it?

Not suggested by us, for these reasons

No person has signed this entry off yet.
At least one source behind the claims has not been read and recorded by a person.

How it is thought to work

We are holding this back. There is a plain-language explanation in our data, but the source behind it has not been read and recorded by a person, so it does not appear here.

What it is said to help with

We are holding these back for the same reason: nobody has read the evidence yet, so we are not going to tell you what this does.

How long before you would know

The timescale in our data is not published yet, because nobody has read the source behind it. What we will say regardless: anything that works on skin works over weeks, not days.

A trial in Skinstreak runs for at least 8 weeks with a reading every 14 days, for the same reason. Shorter intervals mostly produce differences beneath the noise floor.

What it tends to feel like

Irritation risk: Moderate
Commonly reported: Stinging · Dryness · Redness that settles

Who we never suggest this to

These come from our own rules, applied by code before any suggestion is produced. They are not claims about the ingredient — they are statements about what our software will refuse to do, and they are worth reading even if you got this ingredient somewhere else.

If you told us about a course of oral isotretinoin you are on: You told us about oral isotretinoin, so we leave exfoliating acids out.
If you told us about a recent course of oral isotretinoin: You told us about oral isotretinoin, so we leave exfoliating acids out.
If you told us nothing either way about the questions above: You haven't told us whether oral isotretinoin applies to you, and we don't guess. Anything that would matter either way stays out.

A declared allergy, a reaction you reported to us, or an unresolved reaction to anything at all removes this ingredient regardless of everything above.

Layering it with other things

Our layering rules are held in the safety layer rather than here, and their wording is still being checked. Until that is finished we are not going to summarise them on this page.

What we can and cannot do

How it is typically used

Withheld until somebody has read the source. We would rather say nothing than give you a routine we have not checked.

A note that applies to every product on a shelf: an ingredient list gives you ordering, not percentages. Unless a brand declares a strength, nobody can compute one from the label, and any number you see derived that way was invented.

Where it is permitted

The regulatory entry behind this ingredient has not been checked against the instrument it names, so we are not publishing it. Where our data is unsure, the engine gets stricter rather than looser.

This might not work for you

Most of what is known about any ingredient comes from group averages. A group average is a statement about a group. It is not a forecast about you, and nobody selling it can turn it into one.

Plenty of people use an ingredient with good evidence behind it for a full course and measure nothing. That outcome is common, it is not a failure on your part, and it is the single most useful thing we can tell you — because it is the one thing the rest of the industry has no reason to mention.

It is also why the product works the way it does: one change at a time, a baseline first, an uncertainty band on every number, and a plain answer at the end even when the answer is that nothing moved. A verdict of no detectable change is a real answer, and it is the one that saves you money.

And if something does move, we still cannot tell you it was this ingredient rather than the season, your sleep, or the other thing you changed in week four. That is what running one experiment at a time is for.

Evidence we have not read yet

These are the briefs behind this entry: descriptions of the evidence we would need to find before publishing a claim. They are not citations, nobody has read them, and we are showing you our homework rather than a result.

Sources a person has read and recorded, with where inside each one the claim lives.

Read and recordedOur own rule
Skinstreak safety rule S1: a user-declared allergy blocks that ingredient and its listed cross-reactors
Recorded by skinstreak_policy on 2026-08-08
Read and recordedOur own rule
Skinstreak safety rule S3: a reported reaction permanently blocks the implicated active for that user
Recorded by skinstreak_policy on 2026-08-08
Read and recordedOur own rule
Skinstreak safety rule S4: a photosensitising active is always shown with the daily-SPF note
Recorded by skinstreak_policy on 2026-08-08

Not read yetRegulation
Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products
Not read yetStill needed
CITATION REQUIRED — controlled evidence for topical glycolic acid improving skin surface texture at cosmetic concentrations
Not read yetStill needed
CITATION REQUIRED — controlled evidence for topical glycolic acid reducing unevenness of skin tone at cosmetic concentrations
Not read yetStill needed
CITATION REQUIRED — a reviewed monograph for topical glycolic acid covering mechanism, onset timescale and typical cosmetic usage
Not read yetStill needed
CITATION REQUIRED — evidence on barrier disruption from simultaneous use of multiple exfoliating acids
Not read yetStill needed
CITATION REQUIRED — evidence on cumulative irritation when a retinoid and an exfoliating acid are applied in the same routine step
Not read yetStill needed
CITATION REQUIRED — current guidance on the post-oral-isotretinoin window during which exfoliating acids, retinoids, physical exfoliation and waxing are avoided
Not read yetStill needed
CITATION REQUIRED — evidence that this ingredient class increases UV sensitivity and that daily broad-spectrum SPF mitigates it

Ways to obtain it

What we suggest is an ingredient, never a product. A product is only a way to obtain one, and which product you use is not something we have an opinion about.

We do not sell any of these and we earn nothing if you buy one. There is no commission on this page because there is no commission anywhere in this product yet.

We cannot point you at a product for this

The product catalogue compiled into this build is example data, not a real shelf. Every row in it is flagged as a placeholder, so no row in it is offered as a way to obtain anything — including the rows that do name Glycolic acid.

This page is built ahead of time from the catalogue that shipped with it, so the counts above describe that catalogue and not whatever is on the shelf at this moment. The shelf reads the live one.

Open the shelf filtered to Glycolic acid

European labelling puts an ingredient list in descending order of weight, but only down to a small threshold; below it the order carries no information, and no label says where the threshold falls. So we read a position as an ordering and nothing else. We will not turn one into a strength, because the label does not contain one.

Read from catalogue 1.0.0: 50 products, of which 3 name Glycolic acid somewhere in their ingredient list.