Hexapeptide-9: Evidence, Side Effects and Legal Status

Legal status Research chemical Not on the WADA list

Evidence grade C Small or open-label human studies only

Human studies 2 published, approximate count

Half-life Unknown in humans time for levels to halve

Route studied Topical (creams, serums) Cosmetic / topical

Watching Hexapeptide-9?

When Hexapeptide-9's status or evidence changes, it's in the next morning's email.

What it is

Hexapeptide-9 is a short lab-made peptide with the sequence Gly-Pro-Gln-Gly-Pro-Gln, two repeats of a collagen-like pattern. It is sold to skincare brands under the trade name Collaxyl, developed by the French ingredient company Vincience, which became part of Ashland. The idea is that skin cells read it as a fragment of broken-down collagen and respond by making more matrix proteins, including collagen IV, part of the thin membrane that joins the outer skin to the layer below.

The best human data are older company studies. In 2004 Vincience researchers reported a double-blind study in 20 women aged 40 to 62 who used a gel with 3% of their collagen-like hexapeptide plus a second booster ingredient, or a placebo gel, around the eyes twice a day for 4 weeks; wrinkle surface, number and depth fell on silicone skin replicas. The paper does not name the peptide as hexapeptide-9, so the link to Collaxyl is likely but not stated.

Read the full overview 1 more

A 2025 trial in 96 adults, run by researchers at Chinese cosmetics companies Chicmax and Kans Biotech, tested a cyclized version, CHP-9, made by joining the two ends of hexapeptide-9. At 0.002% twice daily for 56 days, it reduced crow's feet and forehead wrinkles more than retinol at the same concentration and more than plain serum. That result applies to the modified molecule, which the authors say lasts much longer in the presence of collagen-digesting enzymes than ordinary hexapeptide-9.

Structure 6 residues

Polar
Gly / Pro / Cys

Sequence: H-Gly-Pro-Gln-Gly-Pro-Gln-OH (GPQGPQ)
Length: 6 amino acids
Molecular weight: 582.6 g/mol
Origin: Synthetic peptide built from a repeated Gly-Pro-Gln motif that mimics collagen fragments

How Hexapeptide-9 works

What it binds to, and what happens inside the body after that, step by step.

Target Fibroblast and keratinocyte signaling for extracellular matrix synthesis (collagen IV, laminin 5); exact receptor unknown

When collagen breaks down, its fragments act as signals that tell skin cells to make new matrix. Hexapeptide-9 is designed to mimic such a fragment. In ex vivo human skin treated with 1% of the peptide, staining showed more laminin 5, collagen III and collagen IV, earlier than with vitamin C. How much hexapeptide-9 survives on and in living skin is a weak point: the 2025 trial authors report that the linear peptide is fully broken down by collagenase in 24 hours in their lab tests.

1 Applied to the skin Used in anti-wrinkle creams and serums.
2 Has to survive and penetrate Linear hexapeptide-9 is broken down quickly by collagen-digesting enzymes in lab tests, and its skin penetration has not been measured.
3 Read as a collagen fragment Skin cells are thought to respond to it as they would to collagen breakdown products; the receptor involved is not identified.
4 More matrix proteins made In ex vivo human skin, 1% peptide raised laminin 5, collagen III and collagen IV staining.
5 Smoother skin The intended result is fewer and shallower wrinkles. Human data are a 20-woman company study of an unnamed collagen-like hexapeptide and a trial of a modified, cyclized version.

What the studies show

Human results and animal results are kept apart below. A result in rats tells you a mechanism is plausible. It does not tell you what happens in a person.

C Evidence

No independent placebo-controlled trial of standard hexapeptide-9 has been published. A 2004 company study in 20 women found fewer wrinkles with a gel containing an unnamed collagen-like hexapeptide plus a booster, and a 2025 trial in 96 adults, run by cosmetics-company researchers, found a cyclized, modified version beat retinol at 0.002%. Lab work in ex vivo human skin shows more collagen IV and laminin 5.

How far the evidence reaches Highest rung: Randomized trials

Cell studies In a dish 1 key study below
Animal studies Rodents and other models None listed
Small human studies Open-label, case series Covered by human data
Randomized trials Placebo-controlled RCTs, meta-analyses 2 key studies below
Regulatory approval Not approved No

Preclinical: tells you a mechanism is plausible Human: tells you what happened in people (2 published studies, approx.)

In people 2

Randomized trial 2025

Novel cyclized hexapeptide-9 outperforms retinol against skin aging: a randomized, double-blinded, active- and vehicle-controlled clinical trial

96 Asian adults aged 30 to 55 in China, almost all women, randomized to cyclized hexapeptide-9, retinol or plain serum (91 completed); authors work for Chinese cosmetics companies Chicmax and Kans Biotech

At 0.002% twice daily for 56 days, the cyclized peptide reduced the number, area and roughness of crow's feet and forehead wrinkles, beating retinol on all but one measure; it tested a modified molecule, not standard hexapeptide-9.

Read the study

Randomized trial 2004

Collagen-like peptide exhibits a remarkable antiwrinkle effect on the skin when topically applied: in vivo study

20 healthy women aged 40 to 62, double-blind, peptide gel or placebo gel around the eyes (randomization method not described)

A gel with 3% collagen-like hexapeptide and 1% booster, twice daily for 4 weeks, reduced total wrinkle surface in 75% of silicone replicas (P<0.003 for wrinkle length); company study that does not name the peptide.

Read the study

In animals and cells 1

Cell / lab 2004

Stimulating effect of collagen-like peptide on the extracellular matrix of human skin: histological studies

Ex vivo human skin samples

Applying 1% of the collagen-like hexapeptide raised laminin 5, collagen III and collagen IV faster than vitamin C, and collagen IV and beta-1 integrin stayed higher with longer treatment.

Read the study

Reviews A framework for the safety evaluation of peptides in cosmetics (2026) Caffeoyl hexapeptide-9 matched sequences in skin matrix proteins such as collagen and showed no toxin or allergen signal in six screening tools.

What nobody has measured yet

These are questions the published research has not answered.

01 Whether standard, linear hexapeptide-9 reduces wrinkles in an independent placebo-controlled trial.
02 Whether the 2004 study peptide is exactly hexapeptide-9; the paper does not name it.
03 How much linear hexapeptide-9 survives skin enzymes and penetrates intact skin.
04 The concentration of hexapeptide-9 in commercial products.
05 Effects of use beyond 8 weeks.

Hexapeptide-9 from discovery to today

2004Vincience researchers publish ex vivo skin data and a 20-woman double-blind wrinkle study of their collagen-like hexapeptide.
2025Chinese trial in 96 adults finds a cyclized hexapeptide-9 at 0.002% reduces wrinkles more than 0.002% retinol over 56 days.
2025The same group reports that linear hexapeptide-9 is fully broken down by collagenase in 24 hours, while the cyclized form mostly survives.
2026Procter & Gamble scientists publish a cosmetic peptide safety framework that screens caffeoyl hexapeptide-9 and finds no toxin or allergen signal.

Approval or regulatory milestoneResearch milestone

Legal and regulatory status

Research chemical Not approved for human use anywhere and no active approval path.

No product containing Hexapeptide-9 is approved as a medicine by the FDA.

Sold only as a cosmetic ingredient, which FDA does not review for efficacy before sale. It has never been developed as a drug, and we found no published safety assessment of hexapeptide-9 by the US Cosmetic Ingredient Review panel as of October 2026. A 2026 industry safety framework screened a related form, caffeoyl hexapeptide-9, with bioinformatic tools and found sequence similarity to skin matrix proteins without toxin or allergen flags. Not named on the WADA list.

Sport (WADA): Not on the World Anti-Doping Agency prohibited list as a named substance.
Compounding pharmacies: Not applicable. Hexapeptide-9 is a cosmetic ingredient and is not on FDA's 503A or 503B bulks lists or category lists.
Read more: Is Hexapeptide-9 banned in sport? WADA section and list wording; How peptide legal status works in the US

How long it stays in the body

Half-life: Unknown in humans
Routes studied: Topical (creams, serums)
Bioavailability: Not measured. The linear peptide is degraded by collagenase in lab tests, and penetration through intact skin is unknown.
Notes: No pharmacokinetic study exists in any species. Cyclizing the peptide is one strategy being tried to make it last longer in skin.

No human half-life has been published for Hexapeptide-9, so we do not draw a clearance curve. Half-lives quoted online for it are usually estimates from animal data.

Doses used in published studies

This table records the doses that trials and approved labels used, with the source for each row. It is a record of research, not a recommendation, and it is open to free members.

Doses used in published research and approved labels2 rows

Checking membershipEach row names the trial or label, the dose, route, frequency, duration and a link to the source. Free account, no card.

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Side effects, higher-risk groups and interactions

2Frequency unknownnot measured in trials

EffectCommonUncommonRareUnknown

Skin irritationNo irritation events were recorded in the 96-person trial of the cyclized form; no tolerability data are published for standard hexapeptide-9.Frequency unknown

Allergic reactionNo published cases. A bioinformatic screen of a related form found no allergen signal, which is not the same as testing in people.Frequency unknown

Groups with specific risks

Do not inject: there are no human safety data for injected hexapeptide-9
Broken, infected or inflamed skin at the application site
Known allergy to any product ingredient

Interactions

No interaction studies exist.
Use with retinoids, acids or vitamin C has not been studied for hexapeptide-9 itself.

Which symptoms are expected and which mean stop and get help: side effects and red flags.

What people say online, checked against the studies

Tap a claim to see what the studies found.

The claim"Hexapeptide-9 beats retinol."MixedSome studies agree, some do not

A 2025 trial found a cyclized, modified hexapeptide-9 beat retinol at 0.002%, a low retinol strength. Standard hexapeptide-9 was not tested, and the authors report it breaks down quickly.

The claim"Hexapeptide-9 adds collagen to your skin."MixedSome studies agree, some do not

It is not collagen and does not become collagen. In ex vivo skin it raised the cells' own collagen III and IV output; whether this happens in living skin from a cream is unproven.

The claim"Collaxyl is clinically proven."MixedSome studies agree, some do not

The supporting human study is a 20-woman company trial from 2004 that tested a gel with a booster ingredient and does not name the peptide. No independent trial of Collaxyl has been published.

Combinations people discuss

These pairings come up often. Almost none have been tested together in a trial, and the evidence note on each says so plainly.

Collagen-signaling peptide blends

Hexapeptide-9 Matrixyl 3000 GHK-Cu

Anti-aging serums combine several matrix-signaling peptides on the idea that they work through different pathways.

EvidenceNo published trial has tested these blends; each peptide's human evidence is limited.

Storage and stability

Dry powder (lyophilized)

Sold mainly as a pre-dissolved cosmetic ingredient; no drug-grade storage guidance exists.

Mixed with water (reconstituted)

Follow the cosmetic product's packaging and expiry date; no independent stability data are published.

Guide Reconstitution and storage, explainedMembers Bacteriostatic water, fridge vs freezer, and how fast peptides break down.

Related peptides

New Hexapeptide-9 research, explained when it is published

One email when a trial reads out, a label changes or the FDA acts on a peptide. Free, every source linked, unsubscribe any time.

Frequently asked questions

What does hexapeptide-9 do for skin?

It is designed to mimic a collagen fragment so skin cells make more matrix proteins such as collagen IV and laminin 5. That was shown in ex vivo skin; in people, the evidence is a small company study and a trial of a modified version.

Is hexapeptide-9 the same as Collaxyl?

Yes. Collaxyl is the trade name for hexapeptide-9, originally from Vincience, now part of Ashland.

Is hexapeptide-9 better than retinol?

Not shown for the standard peptide. A cyclized version beat 0.002% retinol in a 96-person trial, but that is a modified molecule and a low retinol dose.

Is hexapeptide-9 safe?

No safety problems have been published, and a trial of a modified form recorded no irritation. There is no formal safety assessment of standard hexapeptide-9.