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Section 13 · 3 compounds

Skin, Hair & Dermal Signaling

Cosmetic peptides and hair-follicle research, where the route matters.

Home/ Sections/ Skin, Hair & Dermal Signaling

Skin and hair research spans cosmetic ingredients tested in small topical studies and experimental compounds tested only in mice. Results in this section depend heavily on the route used, and a positive finding for a cream says nothing about other routes.

Each entry opens with an evidence grade, then covers how the compound works, what human, animal and cell studies show, safety, open questions and regulatory status, with numbered references. Grades in this section: B: 1 · C: 1 · D: 1.

B
Evidence grade B · Human RCTsWhat this means

A randomized, placebo-controlled split-face trial in 93 women supports a topical cosmetic effect, and the ingredient has no drug approval anywhere[2].

A short collagen fragment with a fatty tail, sold as a cosmetic skin ingredient, with one decent company-run split-face trial showing modest wrinkle improvement.

Overview

Matrixyl is a trade name attached to palmitoyl pentapeptide-4, also written pal-KTTKS. The peptide part, lysine-threonine-threonine-lysine-serine, is residues 212 to 216 of type I procollagen: a fragment released when collagen is processed or broken down. Laboratory work in the early 1990s identified that five-residue stretch as the smallest piece able to push cultured fibroblasts to make more collagen and fibronectin[1]. Cosmetic chemists later attached a 16-carbon palmitic acid tail to make it fat-soluble enough to partition into skin[3].

The name is slippery. Suppliers market several different peptide systems under Matrixyl labels, including blends built around palmitoyl tripeptides, so the published evidence for pal-KTTKS does not automatically transfer to a product carrying the brand. The strongest clinical evidence is a single 12-week split-face trial run by Procter & Gamble researchers[2], supported by a small three-arm trial in Indonesian women[4]. This is cosmetic, topical, appearance-level evidence, not drug evidence[8].

The scrap that tells the crew to rebuildWhen a building is torn down, scraps of the old frame are left on the ground. KTTKS is such a scrap from collagen. The idea is that skin cells read the scrap as proof that demolition happened and start rebuilding. The palmitic tail is the grease that lets the scrap slip through the skin's outer wall.

Mechanism of Action

KTTKS belongs to a family of matrix fragments sometimes called matrikines: pieces of structural protein that act as signals when they break loose. In the original cell work, the pentapeptide drove collagen type I, collagen type III and fibronectin production in several mesenchymal cell types without changing overall protein synthesis, which is why the authors called it the minimum active sequence of a larger propeptide fragment[1]. No receptor for KTTKS on human dermal fibroblasts has been identified, so the signaling step is still a black box[6]. That matters: the whole mechanistic story rests on cultured cells responding to an added peptide, which is a long way from organized repair inside living dermis[6].

Delivery is the second problem. Skin resists most molecules above roughly 500 daltons[7], and pal-KTTKS is about 802 daltons[5]. Adding the palmitoyl tail helps, but only partly. In hairless mouse skin, unmodified KTTKS was not detectable in any skin layer, while pal-KTTKS reached 4.2 ± 0.7 µg/cm² in the stratum corneum, 2.8 ± 0.5 in the epidermis and 0.3 ± 0.1 in the dermis. Neither peptide crossed full-thickness skin into the receptor fluid, and both degraded quickly in skin extracts unless protease inhibitors were added[3]. So the deep compartment gets very little, and what arrives may not arrive intact.

What the Research Shows

Human studies
  • Randomized, double-blind, placebo-controlled split-face trial, 2005 (n=93 women aged 35 to 55, 12 weeks): a moisturizer containing 3 ppm pal-KTTKS produced significant reductions in wrinkles and fine lines versus the same moisturizer without it, by instrumental analysis, expert image grading and subject self-assessment, and was well tolerated. All six authors worked for Procter & Gamble, the trial sponsor[2].
  • Double-blind three-arm randomized trial, 2023 (n=21 Indonesian women aged 26 to 55, 8 weeks, 7 per arm): on the crow's feet grading scale, palmitoyl pentapeptide-4 cream fell 0.86 points for both static and dynamic lines, similar to acetyl hexapeptide-3. Corneometer, Tewameter and Cutometer measures were all non-significant (P>0.05), and the authors called the study preliminary. No complaints were reported in the pentapeptide arm[4].
  • A widely repeated "49 women, 4 months" study is cited in review articles as showing reduced skin roughness, wrinkle volume and wrinkle depth with biopsy-level elastin and collagen IV changes. The citation trail leads to trade-press coverage rather than a peer-reviewed publication, so the primary report could not be verified and its numbers should not be treated as established[5].
  • A 2026 review of peptides in aesthetic dermatology lists the 2005 trial among studies limited by small samples and short follow-up, and notes that the varied vehicles and combined regimens across the field prevent any class-wide efficacy estimate[6].
Animal studies
  • Hairless mouse skin (ex vivo permeation and stability): pal-KTTKS was more stable than KTTKS in skin extracts and homogenates, yet both degraded rapidly without protease inhibitors, and neither crossed full-thickness skin[3].
  • No whole-animal efficacy study of pal-KTTKS on skin aging was located, and no systemic animal toxicology for the peptide was found[3,6].
Cell & mechanistic
  • Human and other mesenchymal fibroblasts: the pentapeptide KTTKS (residues 212 to 216 of type I procollagen) stimulated collagen type I, collagen type III and fibronectin production in a dose- and time-dependent way, identified as the minimum sequence needed for the effect[1].
  • Fibroblast contraction markers: palmitoyl-KTTKS altered wound-contraction markers in experimental models, with effects that the reviewers describe as context-dependent rather than uniformly pro-repair[6].
What This Could Mean in Practice

In practice this is a cosmetic ingredient with better-than-average evidence for a cosmetic ingredient, which is still a low bar. One sponsor-run split-face trial and one 21-person pilot suggest a measurable but modest improvement in the look of fine lines over two to three months of twice-daily topical use[2,4]. It has not been compared head-to-head against retinoids in a published randomized trial, it has no approval as a drug anywhere, and effects on skin structure in living people have not been demonstrated[6,8]. Products carrying the Matrixyl name may not contain this molecule at all.

Safety & Side Effects
  • Topical tolerability: the 12-week trial reported the pal-KTTKS product was well tolerated, with no excess irritation versus the control moisturizer[2].
  • Small pilot data: in the 2023 trial the pentapeptide arm reported no complaints, while the placebo and hexapeptide arms reported itching, stinging and burning in 14% to 29% of their seven-person groups, numbers far too small to compare meaningfully[4].
  • No systemic safety data. Published work covers topical cosmetic use only; there is no human pharmacokinetic, injectable or oral safety data for this peptide[3,6].
  • Delivery uncertainty cuts both ways. Very little intact peptide reaches the dermis in model skin, which limits both expected benefit and systemic exposure[3,7].
  • Identity risk: because several commercial peptide systems share the Matrixyl branding, a product's actual ingredient should be confirmed as palmitoyl pentapeptide-4 before any of this evidence is applied[6].

Open Questions

  • Whether an independent, non-industry group can reproduce the 2005 result. The strongest trial was designed, run and authored entirely by the sponsor's own scientists[2].
  • How much of the measured improvement comes from the peptide rather than the moisturizer base, formulation, or the simple hydration effect seen in vehicle arms of cosmetic trials[4,6].
  • What receptor or pathway KTTKS actually engages in human dermal fibroblasts, which has never been identified[6].
  • Whether enough intact peptide reaches living human dermis at cosmetic concentrations to do anything measurable, given that model skin data show minimal dermal delivery and rapid degradation[3].

Regulatory Status

Palmitoyl pentapeptide-4 is used as a cosmetic ingredient and has no FDA or EMA drug approval for any indication. Cosmetic products generally do not require FDA premarket approval, but a product claiming to change the structure or function of skin rather than its appearance would be regulated as a drug[8]. Review articles treat the clinical evidence as cosmetic and formulation-specific rather than therapeutic[6].

Related Compounds

SNAP-8GHK-CuPTD-DBM
References (8)
  1. Katayama K, Armendariz-Borunda J, Raghow R, et al. A pentapeptide from type I procollagen promotes extracellular matrix production. J Biol Chem. 1993;268(14):9941-4. PMID: 8486721
  2. Robinson LR, Fitzgerald NC, Doughty DG, et al. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci. 2005;27(3):155-60. PMID: 18492182
  3. Choi YL, Park EJ, Kim E, et al. Dermal stability and in vitro skin permeation of collagen pentapeptides (KTTKS and palmitoyl-KTTKS). Biomol Ther (Seoul). 2014;22(4):321-7. PMID: 25143811
  4. Aruan RR, Hutabarat H, Widodo AA, et al. Double-blind, randomized trial on the effectiveness of acetylhexapeptide-3 cream and palmitoyl pentapeptide-4 cream for crow's feet. J Clin Aesthet Dermatol. 2023;16(2):37-43. jcadonline.com
  5. Schagen SK. Topical peptide treatments with effective anti-aging results. Cosmetics. 2017;4(2):16. DOI: 10.3390/cosmetics4020016
  6. Yi KH, Kim HS, Lee HE, et al. Peptides in aesthetic dermatology: classification, fibroblast-centered mechanisms, delivery technologies, and clinical evidence. Life. 2026;16(10):1660. DOI: 10.3390/life16101660
  7. Bos JD, Meinardi MM. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Exp Dermatol. 2000;9(3):165-9. PMID: 10839713
  8. U.S. Food and Drug Administration. Is it a cosmetic, a drug, or both? (Or is it soap?). 2024. fda.gov

Sources last reviewed October 2026.

C
Evidence grade C · Limited humanWhat this means

Human data exist only from small studies of multi-ingredient cosmetic formulations, with no controlled trial of acetyl octapeptide-3 on its own[4,5].

A cosmetic peptide marketed as a gentler stand-in for botulinum toxin, with no controlled trial testing it by itself and a size that makes skin delivery doubtful.

Overview

SNAP-8 is a trade name for acetyl octapeptide-3, a synthetic eight-residue peptide sold as a topical cosmetic ingredient aimed at the appearance of expression lines. It was built by extending acetyl hexapeptide-3 (marketed as Argireline) by two amino acids, and both were designed around the sequence of SNAP-25, a protein in the machinery that releases neurotransmitter at the junction between nerve and muscle[1]. PubChem lists the molecule with the formula C&sub4;&sub1;H&sub7;&sub0;N&sub1;&sub6;O&sub1;&sub6;S and a molecular weight near 1075 daltons[8].

The marketing story is that it relaxes rather than paralyzes, in contrast to botulinum toxin, which cuts SNAP-25[1]. The evidence behind that story is thin. The published clinical work that includes acetyl octapeptide-3 uses formulations containing several active ingredients at once[4], so nothing isolates this peptide's contribution. Reviews of the field treat it as a commercial concept related to acetyl hexapeptide-8 rather than a clinically interchangeable or independently validated ingredient[5].

A decoy part on the assembly lineNerve endings release their signal using a crew of proteins that latch together, SNAP-25 among them. Botulinum toxin works like bolt cutters on that crew. The idea behind SNAP-8 is milder: hand the crew a look-alike part so the real assembly goes together more slowly. Whether enough decoy parts ever reach the crew through skin is the unanswered question.

Mechanism of Action

Nerve-to-muscle signaling depends on SNARE proteins, SNAP-25 among them, assembling into a complex that lets vesicles fuse and dump neurotransmitter. Botulinum neurotoxin type A cleaves SNAP-25, which is why it paralyzes muscle. The cosmetic peptides in this family were designed instead as sequence mimics intended to interfere with assembly or stability of that complex rather than destroy any part of it. For the parent hexapeptide, the original Lipotec-affiliated paper reported inhibition of neurotransmitter release with potency similar to botulinum toxin A but far lower maximal effect, attributed to interference with SNARE complex formation[2]. SNAP-8 is described as the same idea with two extra residues, claimed by its supplier to be more effective and more stable[1]. That claim rests mainly on a product data sheet, not on a published comparison.

Delivery is the harder problem, and it is arithmetic. Topical absorption drops off sharply above roughly 500 daltons[7], and acetyl octapeptide-3 is about twice that[8]. It is also a charged, water-soluble peptide, which does not partition easily into the lipid-rich outer skin layer. That is why most published work pairs it with a delivery vehicle: microneedle patches[1,4] or polymer nanoparticles[10]. Even if the peptide can slow vesicle release in a dish, the relevant target sits at the neuromuscular junction beneath the dermis, and no study has shown that a topical formulation delivers intact peptide there.

What the Research Shows

Human studies
  • Open monocentric study of a multi-active microneedle patch, 2019 (hyaluronic acid microneedles, 12 weeks): fine lines and wrinkles decreased 25.8%, hydration improved 15.4%, skin density rose 14.2% and dermal thickness 12.9%, with no primary or cumulative skin reactions. The patch also contained an arginine/lysine polypeptide, palmitoyl tripeptide-5, adenosine and seaweed extracts, so no part of this result can be assigned to acetyl octapeptide-3. There was no control group, and the authors were affiliated with the companies supplying the product[4].
  • No randomized controlled trial of acetyl octapeptide-3 alone has been published, and no study has compared it against botulinum toxin or against its parent hexapeptide in people[4,5].
  • For context, the parent peptide acetyl hexapeptide-3 does have human data: a Lipotec-affiliated report described up to 30% reduction in wrinkle depth after 30 days of a 10% emulsion in healthy women volunteers[2], and an independent randomized placebo-controlled study in 60 Chinese subjects over 4 weeks reported 48.9% total anti-wrinkle efficacy versus 0% for placebo on subjective grading, with significant roughness reductions on replica analysis (P<0.01)[3]. These numbers belong to a different molecule and are often quoted as though they apply to SNAP-8[6].
Animal studies
  • No published animal efficacy or toxicology study of acetyl octapeptide-3 was located. The peptide's literature consists of analytical chemistry, formulation work and cosmetic studies[1,10].
Cell & mechanistic
  • Formulation and cytotoxicity screening: glutamic-acid-functionalized polymer nanoparticles loaded acetyl octapeptide-3 to a maximum capacity of 220.69 mg/g and were reported non-toxic on Alamar Blue and LDH assays, work aimed at controlled release rather than at testing the peptide's proposed mechanism[10].
  • No published cell study demonstrates that acetyl octapeptide-3 itself inhibits neurotransmitter release; that evidence exists for the shorter parent peptide and for SNAP-25 fragments generally[2,5].
What This Could Mean in Practice

In practice, a product containing SNAP-8 is a cosmetic whose specific contribution has never been measured. The one 12-week study that included it tested a five-ingredient microneedle patch with no control arm and industry authorship[4], and the eye-catching percentages that circulate alongside the name mostly come from its shorter cousin, a different molecule[2,3]. Comparisons to injectable botulinum toxin are not supported by any published head-to-head work[5]. If an effect exists, the likeliest route for it is formulation and delivery rather than the peptide itself[1,7].

Safety & Side Effects
  • Topical tolerability looks unremarkable: the microneedle study reported no primary or cumulative skin reactions over 12 weeks, though in a small uncontrolled sample[4].
  • No systemic safety data. There is no human pharmacokinetic, injectable or oral safety data for acetyl octapeptide-3[1,5].
  • No animal toxicology. No repeated-dose, genotoxicity or reproductive studies for this peptide were located[1,10].
  • Delivery routes change the risk picture. Microneedle and nanoparticle systems are designed specifically to breach the barrier that limits a 1075-dalton peptide[1,4,8], so safety conclusions drawn from a simple cream do not transfer to them.
  • Mechanism-based uncertainty: if a formulation ever did deliver meaningful amounts of a SNARE-interfering peptide to neuromuscular junctions, effects on muscle function would need to be studied rather than assumed benign. No study has examined this[2,5].

Open Questions

  • What acetyl octapeptide-3 does on its own. Every human dataset that includes it is multi-ingredient, uncontrolled or both[4].
  • Whether any topical formulation delivers intact peptide past the stratum corneum in human skin, given its size and charge[7,8].
  • Whether the supplier claims of greater potency and stability than acetyl hexapeptide-3 hold up, since they trace to a product data sheet rather than a published comparison[1].
  • How much of the peptide survives manufacturing and storage in a given product, a question raised directly by analytical work showing matrix effects and the need for matrix-matched quantification[1].

Regulatory Status

Acetyl octapeptide-3 is a cosmetic ingredient with no FDA or EMA drug approval and no recognized therapeutic indication. Cosmetics generally do not need FDA premarket approval, but claims about relaxing muscle or otherwise changing the structure or function of the body would make a product a drug in FDA's view[9]. Reviews caution against treating it as equivalent to botulinum toxin or to related cosmetic peptides[5].

Related Compounds

MatrixylGHK-CuPTD-DBM
References (10)
  1. Ji M, Lee HS, Kim Y, et al. Method development for acetyl octapeptide-3 analysis by liquid chromatography-tandem mass spectrometry. J Anal Sci Technol. 2020;11:34. DOI: 10.1186/s40543-020-00232-8
  2. Blanes-Mira C, Clemente J, Jodas G, et al. A synthetic hexapeptide (Argireline) with antiwrinkle activity. Int J Cosmet Sci. 2002;24(5):303-10. PMID: 18498523
  3. Wang Y, Wang M, Xiao S, et al. The anti-wrinkle efficacy of argireline, a synthetic hexapeptide, in Chinese subjects: a randomized, placebo-controlled study. Am J Clin Dermatol. 2013;14(2):147-53. PMID: 23417317
  4. Avcil M, Akman G, Klokkers J, et al. Efficacy of bioactive peptides loaded on hyaluronic acid microneedle patches: a monocentric clinical study. J Cosmet Dermatol. 2020;19(2):328-37. PMID: 31134751
  5. Yi KH, Kim HS, Lee HE, et al. Peptides in aesthetic dermatology: classification, fibroblast-centered mechanisms, delivery technologies, and clinical evidence. Life. 2026;16(10):1660. DOI: 10.3390/life16101660
  6. Schagen SK. Topical peptide treatments with effective anti-aging results. Cosmetics. 2017;4(2):16. DOI: 10.3390/cosmetics4020016
  7. Bos JD, Meinardi MM. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Exp Dermatol. 2000;9(3):165-9. PMID: 10839713
  8. National Center for Biotechnology Information. PubChem Compound Summary for CID 76283482, Acetyl octapeptide-3. pubchem.ncbi.nlm.nih.gov
  9. U.S. Food and Drug Administration. Is it a cosmetic, a drug, or both? (Or is it soap?). 2024. fda.gov
  10. Baglamis S, Feyzioglu-Demir E, Akgol S. New insight into anti-wrinkle treatment: using nanoparticles as a controlled release system to increase acetyl octapeptide-3 efficiency. Polym Bull. 2023;80(12):12659-81. DOI: 10.1007/s00289-022-04663-8

Sources last reviewed October 2026.

D
Evidence grade D · Animal onlyWhat this means

All published PTD-DBM work is in cells and mice, from one Korean laboratory group, with no human trials[1,4].

An engineered peptide that pries a brake off the Wnt signaling pathway, studied in mice for wound healing and hair regrowth, never tested in people.

Overview

PTD-DBM is a two-part laboratory peptide: a protein transduction domain, which carries it into cells, fused to a Dishevelled-binding motif. The motif is copied from CXXC5, a protein that acts as a negative feedback brake on Wnt/beta-catenin signaling by latching onto Dishevelled. The peptide is designed to occupy that latch point so CXXC5 cannot, which lets Wnt signaling run[1]. It is a tool for interrupting a protein-to-protein handshake rather than a hormone, a growth factor, or anything that supplies a missing substance.

The compound comes almost entirely from one research network at Yonsei University in Korea and affiliated companies. The same group published CXXC5 as a wound-healing brake in 2015[1], as an osteoblast brake the same year[2], then screened small molecules targeting the identical interaction[3], then reported hair regrowth and wound-induced hair neogenesis in mice with the competing peptide in 2017[4]. Work since 2020 has largely shifted to orally available small molecules rather than the peptide[6].

Taking the parking brake off, not pressing the gasWnt signaling is the engine that tells hair follicles and healing skin to build. CXXC5 is a parking brake the body leaves on to keep that engine from racing. PTD-DBM does not touch the gas pedal. It slips into the slot the brake handle uses, so the brake cannot engage. The engine then idles higher on its own.

Mechanism of Action

Wnt/beta-catenin signaling runs through Dishevelled (Dvl), a hub protein that relays the signal from surface receptors inward. CXXC5 binds Dvl in a Wnt-dependent way, which makes it a negative feedback regulator: the more the pathway fires, the more CXXC5 shuts it down. The original paper showed CXXC5 levels fall in human keratinocytes and fibroblasts during acute wounding, and that CXXC5-knockout mice heal faster with more keratin 14 and collagen, which framed CXXC5 as a brake worth releasing[1]. The crystal structure of the Dvl PDZ domain with CXXC5 has since been solved, and the same interaction has been targeted with small molecules, so the binding site itself is reasonably well characterized[3].

PTD-DBM is the peptide version of that strategy, carrying the Dvl-binding motif plus a transduction tag to get inside cells. In the wound work it raised beta-catenin activity and collagen production in culture, and in mice it accelerated healing most clearly when combined with valproic acid, a GSK3-beta inhibitor that pushes the same pathway from a different angle[1]. That combination detail matters: the strongest animal effects were reported for peptide plus a second agent, not for the peptide alone. In bone work from the same group, the competing peptide activated Wnt signaling and osteoblast differentiation and thickened cultured calvariae, but the animal experiments were run with small molecules rather than the peptide[2,3].

What the Research Shows

Human studies
  • No clinical trial of PTD-DBM has been published, and no human pharmacokinetic, dosing, efficacy or safety data exist[1,4].
  • The only human material in this literature is tissue: CXXC5 protein levels were measured in human keratinocytes and fibroblasts and found to drop during acute wounding, which supports the target's relevance but says nothing about the peptide[1].
  • Human hair-loss efficacy, formulation, skin penetration and long-term safety are all unestablished, which is how review commentary in the field treats the approach[5].
Animal studies
  • Mice, cutaneous wound model: CXXC5-knockout animals healed faster than wild type, and a peptide blocking the CXXC5-Dishevelled interaction combined with valproic acid accelerated healing more than either agent alone[1].
  • Mice, hair regrowth and wound-induced hair neogenesis: targeting CXXC5 with the competing peptide stimulated hair regrowth and new follicle formation after wounding, the result that made this peptide known outside the Wnt field[4,6].
  • Mouse calvariae (ex vivo) and bone: the competing peptide activated Wnt/beta-catenin signaling and osteoblast differentiation and increased thickness growth of cultured calvariae; the live-animal bone experiments used small-molecule inhibitors of the same interaction, not the peptide[2,3].
  • No published toxicology, carcinogenicity or reproductive studies of PTD-DBM were located in any species[1,4].
Cell & mechanistic
  • Fibroblasts and keratinocytes: blocking the CXXC5-Dishevelled interaction increased beta-catenin transcriptional activity and collagen production[1].
  • Osteoblast precursors: the same blockade activated Wnt/beta-catenin signaling and promoted osteoblast differentiation, establishing that the effect is not skin-specific[2].
What This Could Mean in Practice

In practice this is an interesting target with a preclinical tool attached, not a hair-loss treatment. Mouse data from one group suggest that releasing the CXXC5 brake can push follicles into growth and speed wound closure, with the clearest effects when a second Wnt-activating agent was added[1,4]. Nobody has published what happens in a human scalp, how much peptide reaches a follicle through skin, or what chronic pathway activation does. That last question is not idle: Wnt/beta-catenin is a pathway whose persistent activation is linked to tumor formation in multiple tissues, and no study has addressed it for this peptide[3,5].

Safety & Side Effects
  • No human safety data at all. No trial, no tolerability report, no adverse-event data[1,4].
  • No animal safety package. The mouse studies report efficacy endpoints; no dedicated repeated-dose toxicology, genotoxicity or reproductive studies for PTD-DBM were located[1,4].
  • Pathway-level concern: Wnt/beta-catenin activation drives proliferation, and sustained activation of this pathway is implicated in tumorigenesis. No published work examines tumor risk with this peptide[2,3].
  • Combination effects unstudied in people: the strongest mouse results pair the peptide with valproic acid, a drug with its own substantial toxicity profile, and that combination has no human data[1].
  • Research-grade material is not a medicine. Peptide sold for laboratory use carries no assurance of identity, purity, sterility or endotoxin control suitable for human exposure.

Open Questions

  • Whether the mouse hair results replicate outside the originating group. Nearly all of this literature shares senior authorship, and several papers list authors affiliated with a company built around the target[6].
  • Whether a topically applied peptide of this size reaches hair-follicle stem cells in human scalp, which no published study measures[4].
  • Whether effects require the second agent. The wound data were strongest for peptide plus valproic acid, and the bone animal work used small molecules instead of the peptide[1,2,3].
  • What chronic Wnt activation does to skin and other tissues over months, including proliferative and tumor risk, which remains entirely unexamined for this compound[3,5].
  • Why development appears to have moved toward orally available small molecules targeting the same interaction rather than the peptide, which the published record does not explain[3,6].

Regulatory Status

PTD-DBM has no approval from the FDA, EMA or any other major regulator, and no registered clinical trial of it was located. It is not a recognized compounding substance. Having no approval from any governmental regulatory health authority for human therapeutic use, it falls within WADA class S0, prohibited in sport at all times[7].

Related Compounds

MatrixylGHK-CuAHK-Cu
References (7)
  1. Lee SH, Kim MY, Kim HY, et al. The Dishevelled-binding protein CXXC5 negatively regulates cutaneous wound healing. J Exp Med. 2015;212(7):1061-80. PMID: 26056233
  2. Kim HY, Yoon JY, Yun JH, et al. CXXC5 is a negative-feedback regulator of the Wnt/beta-catenin pathway involved in osteoblast differentiation. Cell Death Differ. 2015;22(6):912-20. PMID: 25633194
  3. Kim HY, Choi S, Yoon JH, et al. Small molecule inhibitors of the Dishevelled-CXXC5 interaction are new drug candidates for bone anabolic osteoporosis therapy. EMBO Mol Med. 2016;8(4):375-87. PMID: 26941261
  4. Lee SH, Seo SH, Lee DH, et al. Targeting of CXXC5 by a competing peptide stimulates hair regrowth and wound-induced hair neogenesis. J Invest Dermatol. 2017;137(11):2260-9. PMID: 28595998
  5. Kim D, Garza LA. The negative regulator CXXC5: making WNT look a little less Dishevelled. J Invest Dermatol. 2017;137(11):2248-50. PMID: 28967390
  6. Seo SH, Lee D, Lee SH, Choi KY. Blockade of CXXC5-dishevelled interaction inhibits adipogenic differentiation, obesity, and insulin resistance in mice. Sci Rep. 2022;12(1):20669. PMID: 36450849
  7. World Anti-Doping Agency. 2026 Prohibited List, S0 Non-approved substances (effective 1 January 2026). wada-ama.org

Sources last reviewed October 2026.

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