Acetyl Tetrapeptide-3 (Topical) Dosage Protocol

Quickstart Highlights

Acetyl Tetrapeptide-3 is a four-residue cosmetic peptide with an acetyl group on the N-terminus and an amide on the C-terminus: Ac-Lys-Gly-His-Lys-NH₂, usually written Ac-KGHK-NH₂. PubChem lists the formula as C₂₂H₃₉N₉O₅^[1]; Cayman Chemical, BOC Sciences and Creative Peptides all give the same sequence with MW 509.6 g/mol and CAS 827306-88-7^[2][5][6]. The nitrogen count is a useful sanity check on the identity: four backbone nitrogens, two on the lysine side chains, two in the histidine imidazole and one in the terminal amide — nine, which is what the formula says.

Look at the middle of that sequence and you will see G–H–K: the same glycyl-histidyl-lysyl motif that sits at the centre of GHK-Cu. That is a genuine structural relationship and it is also the easiest way to be misled about this molecule, because there is no copper here and the large GHK-Cu literature does not transfer to it. What people actually buy is not the powder either: it is Capixyl™, a trade complex of the peptide with red clover extract, and almost everything written about “acetyl tetrapeptide-3” online is really about that complex.

Dosing & Application

Acetyl Tetrapeptide-3 is applied to the scalp or skin inside a finished formulation, so the only quantity that means anything is the concentration of peptide in that formulation. Three numbers circulate for this ingredient. Two of them describe a different material, and the third is an in-vitro concentration that nobody markets. Sorting them out is most of what this page is for.

Standard / Gradual Approach

The number everybody quotes, and what it is actually about. Distributor and supplier listings for Capixyl™ give a recommended use level of 1–5% and describe the material as a clear, colourless to pale yellow liquid with the INCI butylene glycol (and) aqua (and) dextran (and) acetyl tetrapeptide-3 (and) Trifolium pratense (clover) flower extract^[4]. Butylene glycol and water are the first two entries, which is the ordinary signature of a dilute solution. So 1–5% is a percentage of a solution, and the peptide is one of five things in it.

The conversion cannot be done, and that is the honest answer. With Procapil the manufacturer’s dossier states outright that “2 ppm biotinyl-GHK” equals “1% PROCAPIL”, which lets anyone close the arithmetic. No equivalent statement is public for Capixyl. Searched on 24 August 2026, the technical file is a font-subset PDF whose text cannot be extracted, and the two ingredient databases that carry the datasheet refuse automated access^[4][7]. Which means: if a formula label says “5% Capixyl”, you do not know how much peptide is in it, and neither does anyone else outside Lucas Meyer. Any page that hands you a ppm figure for this peptide is guessing.

The one concentration with a published number is in vitro, and it is tiny. Cayman Chemical’s product data record that acetyl tetrapeptide-3 “enhances type III collagen and total laminin protein production in human fibroblasts at 1 µM” and counteracts corticoid-induced reductions in collagen VII at the dermal-epidermal junction in skin samples^[2]. One micromolar of a 509.6 g/mol peptide is 0.51 mg per litre — 0.51 ppm, or 0.000051%. That is a cell-culture medium concentration, not a formulation target, but it is the only quantity attached to a measured effect on this molecule anywhere.

What happens if the blend percentage is applied to powder. Five percent of raw powder is 50,000 ppm. Against the 0.51 ppm in the fibroblast assay that is roughly 98,000×. Nobody has tested anything like it on a human scalp, no safety assessment covers it, and the cost alone is prohibitive — at the 1 g / $299 pack price on one supplier’s catalogue^[5], a single 100 g batch at 5% would consume five grams of peptide. When a formula at that strength is being sold cheaply, the arithmetic says it is not really at that strength.

Supplies Needed

This is a cosmetic raw material. There is nothing to reconstitute, nothing to inject, and no vial in the research-peptide sense. Checked on 24 August 2026: BOC Sciences sells the powder at >95% purity in a 1 g pack and lists the trade names Capixyl, Folixyl and Kollaren 6^[5]; Creative Peptides catalogues it as CPC1690 with the same CAS, formula and sequence and describes it as soluble in DMSO^[6]; Cayman Chemical supplies research-reagent quantities at ≥95%^[2]. The pre-diluted Capixyl complex is sold separately by cosmetic distributors^[4]. What you need is a formulation to put it in, an accurate way to measure a very small mass, and a batch certificate of analysis quoting CAS 827306-88-7.

Acetyl Tetrapeptide-3

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Protocol Overview

The structure of this page follows the only sequence that makes sense for a cosmetic peptide: establish which material a percentage refers to, establish what has actually been measured, and only then convert anything into milligrams. Skipping the first step is how a 0.000051% in-vitro concentration turns into a 5% DIY serum.

The evidence base is one clinical paper and a set of supplier assays. The clinical paper is the strongest thing this ingredient has, and it does not test the ingredient. A 24-week randomised trial in 32 people with mild-to-moderate androgenetic alopecia compared a herbal extract combination of biochanin A, acetyl tetrapeptide-3 and ginseng extracts against 3% minoxidil solution, both applied 1 mL twice daily^[3]. Terminal hair counts rose 8.3% in the combination arm and 8.7% in the minoxidil arm, with no statistically significant difference between them.

That result is quoted everywhere as “as effective as minoxidil”. Read the design instead: 32 subjects, three actives in one bottle, and no placebo arm. With no placebo, a small trial in which both groups improve cannot separate treatment effect from regression to the mean, seasonal shedding and the measurement itself; and with three actives, even a real effect could not be assigned to the peptide. The authors themselves recommend larger groups and longer follow-up^[3].

Dosing Protocol

Reference conversions only. Each row starts from a concentration of peptide in a finished product, gives the mass a 100 g batch would need, and states what a single gram of powder covers. The first row is the only concentration with a measured effect behind it. The last two rows show what happens when a percentage written for the Capixyl liquid is applied to raw powder instead.

Storage Instructions

Keep the powder cool, dry, dark and tightly closed, and follow the batch-specific guidance on the certificate of analysis rather than a generic rule. Suppliers ship it as a lyophilised powder and describe it as soluble in DMSO^[6]; short-peptide powders of this kind are hygroscopic, so humidity matters as much as temperature.

Add it late and cool. The standard formulator instruction for small water-soluble cosmetic peptides is to incorporate them at the cool-down stage rather than into a heated phase. That is a general handling convention for the class, not a stability study of your particular formula — if the batch certificate says something different, the certificate wins.

A stock solution has a shelf life of its own. At any documented concentration the mass per batch is far below what an ordinary balance resolves, so a stock solution is the practical route. An unpreserved aqueous peptide solution is also a growth medium: it needs a preservative system and a date on the bottle. Once the peptide is inside a finished product, it is the product’s preservation that governs.

Important Notes

These are the points that disappear the moment this ingredient reaches a marketing page.

• ▪The single most important correction on this page. “Use at 1–5%” is an instruction about Capixyl™, a clear pre-diluted liquid containing five ingredients^[4]. It is not an instruction about acetyl tetrapeptide-3 powder, and because the peptide’s share of Capixyl is not published, the instruction cannot be translated. A DIY formula using 1–5% raw powder is not following the manufacturer; it is inventing a concentration that has never been tested.
• ▪PubMed indexes exactly two records for this molecule, and only one of them is about it. Searched 24 August 2026, the query “acetyl tetrapeptide-3” returns two results^[7]. One is the 2020 androgenetic-alopecia trial^[3]. The other is a transdermal microneedle study whose model peptides were tetrapeptide-3 (Gly-Gln-Pro-Arg) and acetyl hexapeptide-3^[8] — different molecules, matched only because the search engine split the term. So the honest count is one.
• ▪The one trial had no placebo arm, and that is not a technicality. Both arms of the 24-week study improved by about 8%, and the paper reports no significant difference between them^[3]. In a 32-person trial, “no significant difference” is at least as likely to mean the study was too small to detect one as it is to mean the two treatments are equivalent. Without a placebo arm there is also no way to know how much of either 8% would have happened anyway.
• ▪Three actives went into that bottle. The tested product was biochanin A, acetyl tetrapeptide-3 and ginseng extracts together^[3]. Biochanin A is a red-clover isoflavone with its own 5-alpha-reductase story, and it is the reason Capixyl pairs the peptide with Trifolium pratense in the first place^[4]. Any effect the combination had is unassigned between the three.
• ▪The GHK inside the sequence is not a licence to borrow the GHK-Cu evidence. Ac-Lys-Gly-His-Lys-NH₂ contains the GHK motif, but it is acetylated, amidated, carries an extra lysine and, decisively, is not bound to copper. The copper complex’s activity is a property of the complex. If you want the GHK-Cu evidence, read our GHK-Cu protocol; it does not carry over to this molecule.
• ▪The in-vitro claims are supplier-generated. The type III collagen, laminin and collagen VII findings come from product literature, not from an independent peer-reviewed paper^[2]. That does not make them false. It does mean they have not been through external review, and they were produced by a party with an interest in the outcome.
• ▪It is not a hair-loss treatment. No approval, no drug status, no regulatory claim — a cosmetic ingredient whose entire human evidence base is one small three-active trial. It is not a substitute for minoxidil or finasteride, and nothing on this page should be read as advice to replace either.

How This Works

The proposed mechanism is extracellular-matrix signalling rather than hormonal. Supplier assays report that at 1 µM the peptide raises type III collagen and total laminin production in cultured human fibroblasts, and that it counteracts corticoid-induced falls in collagen VII at the dermal-epidermal junction of human skin samples^[2]. Collagen VII and laminin are anchoring proteins: the logic being sold is that a follicle held more firmly in the dermis sheds less readily.

That is the same argument made for biotinoyl tripeptide-1, whose supplier dossier attributes its effect to collagen IV and laminin 5 for exactly the same reason. It is a plausible mechanism, it is not a proven one in humans, and in both cases the assays behind it were run by the party selling the material. Anchorage measured in a dish is not shedding measured on a head.

The second half of the Capixyl story is not the peptide at all. Biochanin A, the red-clover isoflavone paired with it, is the ingredient carrying the 5-alpha-reductase claim — the DHT pathway that minoxidil does not touch and finasteride does^[4]. When a Capixyl result is described as working “on DHT”, that is a statement about the clover extract, not about acetyl tetrapeptide-3.

Lifestyle Factors

Judge it on a hair cycle, not on a month. The one controlled study ran 24 weeks^[3], and that length is not arbitrary — it is roughly what it takes for a shift in the anagen/telogen balance to become visible as terminal hairs. Photographs taken at four or six weeks are measuring normal shedding variation.

Attribute results honestly. Almost every product carrying this peptide also carries clover extract, caffeine, redensyl, saw palmetto or minoxidil. The published record for this whole category is of combinations, which means a good outcome from a multi-active serum gives you no basis at all for crediting the peptide. If you want to know what the peptide does, that is not the experiment.

Keep the regulatory position straight. This is a cosmetic ingredient. It has no approval for treating hair loss anywhere, its human evidence base is a single small trial of a three-ingredient product, and the mechanistic work behind it is supplier-run in-vitro data. Treat it as an optional addition to a hair routine, never as a therapy, and never as a reason to stop something that is working.

Potential Benefits & Side Effects

What follows separates what has been measured from what is claimed. Almost everything attributed to this peptide in marketing copy belongs to the Capixyl complex or to a fibroblast dish; the list below keeps those apart.

How to Apply

There is nothing to reconstitute and nothing to inject. What follows is the workflow for turning a powder into a finished topical without inheriting somebody else’s percentage, and for judging the outcome honestly afterwards. Educational reference — not a formulation service, and not medical advice.

Skin Preparation

• ▪Confirm the identity before anything else. The checks are CAS 827306-88-7, PubChem CID 11752568, formula C₂₂H₃₉N₉O₅, MW 509.6, sequence Ac-Lys-Gly-His-Lys-NH₂^[1][2][6]. Purity on the supplier sheets checked ranged from ≥95% to >95%^[2][5]. Ask for the batch certificate rather than accepting the catalogue description.
• ▪Establish which material you are holding. Raw powder and Capixyl™ liquid are two different things with two different percentages attached to the same INCI name^[4]. Write down which one is in front of you before doing any arithmetic at all — this is the step that goes wrong.
• ▪Accept that there is no validated target concentration for the powder. The only measured number is 1 µM in cell culture, which is 0.51 ppm^[2]. Anything else on the table above is arithmetic, not evidence, and the honest position is to say so rather than to pick a figure and defend it.

Applying the Product

• ▪Work out the mass, then decide whether you can weigh it. A 100 g batch at 10 ppm needs 1 mg, which is below what an ordinary balance resolves. The working method is a stock solution: 100 mg in 100 mL of water gives 1 mg/mL, and 1 mg is then 1 mL by pipette.
• ▪Add it to the water phase, late and cool. Small water-soluble cosmetic peptides are conventionally incorporated at the cool-down stage rather than the heated phase. Suppliers list DMSO solubility for laboratory use^[6]; DMSO in a leave-on scalp product is a separate decision with its own consequences.
• ▪If you want the trial to be relevant, apply it the way the trial did. The 24-week study used 1 mL twice daily to the scalp^[3]. A different frequency, a rinse-off vehicle or a once-daily routine is a different experiment, and the published result stops applying to it.
• ▪Do not scale a small number up because it looks like nothing. Half a part per million weighs nothing on a scale, and that is precisely the concentration at which the only measured effect was seen. The figure is small because the studies were, not because it needs correcting.

After Application

• ▪Give it 24 weeks before judging it. That is the length of the only controlled study^[3], and it is roughly one hair cycle. Assessments before then measure shedding variation, not response.
• ▪Change one thing at a time. If the formula also contains clover extract, caffeine, redensyl, saw palmetto or minoxidil, you will not learn anything about this peptide from the result — which is exactly the problem with the published literature on it.
• ▪Keep expectations proportionate to the evidence. One small trial of a three-ingredient product, no placebo arm, and supplier-run in-vitro work. That is the whole file. It is a reasonable optional addition to a hair routine and it is not a treatment for hair loss.

Recommended Source

For high-purity research peptides, we point researchers to Prime Lab Peptides for Acetyl Tetrapeptide-3 (1-5% (blend)).

References

1. 1
   PubChem CID 11752568 — Acetyl tetrapeptide-3. National Center for Biotechnology Information.

   The chemical identity record: molecular formula C₂₂H₃₉N₉O₅. Used here as the independent check on the sequence given by the three suppliers cited below. Retrieved 24 August 2026.

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2. 2
   Cayman Chemical — Acetyl Tetrapeptide-3 (acetate), item no. 27151

   Product record giving the sequence as Ac-Lys-Gly-His-Lys-NH₂, formula C₂₂H₃₉N₉O₅ • XC₂H₄O₂, molecular weight 509.6, purity ≥95%. It is also the source of the only two concentration-linked biological claims on this molecule: that it enhances type III collagen and total laminin protein production in human fibroblasts at 1 µM, and that it counteracts corticoid-induced reductions in collagen VII expression at the dermal-epidermal junction in human skin samples. Supplier product literature, not peer-reviewed. Retrieved 24 August 2026.

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3. 3
   Journal of Clinical and Aesthetic Dermatology (2020) — An Herbal Extract Combination (Biochanin A, Acetyl tetrapeptide-3, and Ginseng Extracts) versus 3% Minoxidil Solution for the Treatment of Androgenetic Alopecia: A 24-week, Prospective, Randomized, Triple-blind, Controlled Trial

   Lueangarun S, Panchaprateep R. J Clin Aesthet Dermatol 2020;13(10):32–37 (PMID 33584955, PMC7840088). The only PubMed-indexed study of this peptide. Thirty-two subjects (16 male, mean age 41.3 ± 13.8) with mild-to-moderate androgenetic alopecia, randomised to twice-daily 1 mL applications of the herbal extract combination or 3% minoxidil solution for 24 weeks. Terminal hair counts rose 8.3% (p=0.009) in the combination arm and 8.7% (p=0.002) in the minoxidil arm, with no statistically significant difference between them. No local adverse reactions in the combination arm; one minoxidil subject developed scalp eczema. Three actives in one bottle and no placebo arm; the authors recommend larger groups and longer follow-up. Retrieved from PubMed, 24 August 2026.

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4. 4
   Lucas Meyer Cosmetics (Clariant) — Capixyl™ hair care active, distributor technical listing

   The source of the “1–5%” figure and the reason this page exists. Gives the INCI as Butylene Glycol (and) Aqua (and) Dextran (and) Acetyl Tetrapeptide-3 (and) Trifolium Pratense (Clover) Flower Extract, a recommended use level of 1–5%, and the physical form as a clear, colourless to pale yellow liquid — that is, a pre-diluted solution in which the peptide is one of five ingredients. The peptide’s w/w share of the complex is not stated in this or any other public source located on 24 August 2026, which is why no ppm conversion is offered on this page. Retrieved 24 August 2026.

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5. 5
   BOC Sciences — Acetyl Tetrapeptide-3, CAS 827306-88-7

   Independent supplier record confirming the sequence Ac-Lys-Gly-His-Lys-NH2, formula C22H39N9O5, molecular weight 509.60 and purity >95%, and establishing how the material is really sold: a 1 g pack listed in stock at $299, with bulk quantities to order. Also lists the trade names under which the peptide is marketed — Capixyl, Folixyl and Kollaren 6. Retrieved 24 August 2026.

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6. 6
   Creative Peptides — Acetyl Tetrapeptide-3, catalogue no. CPC1690

   A third independent supplier record matching the same identity: CAS 827306-88-7, C22H39N9O5, MW 509.6, sequence Ac-Lys-Gly-His-Lys-NH2 (KGHK), described as soluble in DMSO and supplied for cosmetic formulation work. Pack sizes are quoted on request rather than published. Retrieved 24 August 2026.

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7. 7
   PubMed — literature search for “acetyl tetrapeptide-3”

   Run on 24 August 2026 against the PubMed E-utilities interface. The query returns two records in total. One is the 2020 androgenetic-alopecia trial cited above. The other is the microneedle permeation study listed next, which matched only because the search engine split the term and does not contain this molecule. The honest count of published studies of acetyl tetrapeptide-3 is therefore one, and it tested a three-ingredient product.

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8. 8
   Acta Pharmaceutica Sinica B (2014) — Enhanced delivery of hydrophilic peptides in vitro by transdermal microneedle pretreatment

   Zhang S, Qiu Y, Gao Y. Acta Pharm Sin B 2014;4(1):100–4 (PMID 26579370, DOI 10.1016/j.apsb.2013.12.011). Listed here only to be discounted. Its four model peptides were tetrapeptide-3 (Gly-Gln-Pro-Arg, 456.6 Da), a hexapeptide, acetyl hexapeptide-3 and oxytocin — not acetyl tetrapeptide-3. It appears in the PubMed result set for this molecule as a term-splitting false positive, and any page citing it as evidence for acetyl tetrapeptide-3 has misread the record.

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