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PTD-DBM

A cell-penetrating peptide that pries the Wnt brake CXXC5 off Dishevelled, restarting follicle neogenesis in mouse skin — currently the most interesting preclinical hair compound in the peptide world.

Also known as Protein transduction domain-Dishevelled binding motif, CXXC5 inhibitor peptide, PTD-DBM peptide

Animal data only — Rodent or other animal studies. Dose translation to humans is genuinely uncertain.

All efficacy data come from mouse models and dermal papilla cell culture. There are no completed human trials and no regulatory filings, and the wound-induced neogenesis result — genuinely remarkable if it translated — has not been reproduced in people.

How it works

Wnt/beta-catenin signalling drives the anagen phase and hair follicle neogenesis; CXXC5 is a negative regulator that binds the PDZ domain of Dishevelled and prevents downstream signal transmission. PTD-DBM fuses a protein transduction domain, which gets the peptide across the cell membrane, to the Dishevelled-binding motif of CXXC5 itself, so it acts as a competitive decoy: it occupies Dvl, displaces endogenous CXXC5, and lets beta-catenin accumulate and enter the nucleus. In mouse work this produced hair regrowth and, striking to anyone who has followed the field, wound-induced hair follicle neogenesis — new follicles forming in healed skin. Combining it with valproic acid, which activates Wnt upstream by inhibiting GSK-3beta, produced larger effects than either alone. None of this has been shown in humans.

Targets: CXXC5, Dishevelled PDZ domain, Wnt/beta-catenin signalling, Dermal papilla cells

Dosing

ProtocolDoseFrequencyRoute
Anecdotal topical scalp protocolApplied to a dry scalp at night and left on.—once dailytopical
  • · There is no validated human dose. Community protocols reconstitute 5-10 mg into 5-10 mL of a solvent and apply roughly 1 mL daily, often alongside topical valproic acid, purely by analogy with the mouse work. Treat those numbers as guesses, not guidance.

Cycling

No established cycle. The mouse studies ran continuously for 3-4 weeks.

Work out your exact syringe units →

Pharmacology

Half-life
Not established. Cell-penetrating peptides of this type are typically cleared within hours.
Onset
In mice, visible regrowth over 3-4 weeks of daily application. No human timeline exists.
Routes
topical, intradermal
Molecule
Cell-penetrating fusion peptide (protein transduction domain plus Dvl-binding motif)

Handling

Diluent
Bacteriostatic water or a propylene glycol/ethanol scalp vehicle
Typical mix
5 or 10 mL
Vial sizes
5, 10 mg
Lyophilised
Freezer, sealed and dry.
Reconstituted
Refrigerated; assume a short shelf life of two to four weeks.
Light sensitive
Yes — keep it out of the light

Mixing

Solubility is formulation-dependent and vendor-dependent; there is no standard vehicle for this peptide.

Side effects

  • commonScalp irritation from the vehicle— Usually the propylene glycol or alcohol rather than the peptide.
  • rareUnknown effects from sustained Wnt activation— Wnt/beta-catenin is a growth pathway implicated in several cancers. Nobody has run a long-term human safety study on chronic topical Wnt de-repression.

Do not use if

  • Any history of skin malignancy in the treated area — chronically de-repressing Wnt/beta-catenin in skin is not a risk anyone has quantified.
  • Pregnancy, particularly in combination with valproic acid, which is a known teratogen.

Combining it

  • synergyvalproic-acid — The published combination; GSK-3beta inhibition upstream plus CXXC5 displacement downstream.
  • synergyminoxidil — Entirely different mechanism, so no overlap — but no combination data exist either.

What to monitor

  • · Standardised scalp photography and hair counts in a fixed 1 cm target area.
  • · Inspect any moles or lesions on the treated scalp regularly.

Legal status

Not approved anywhere; sold only as a research chemical. Not a recognised cosmetic ingredient.

References

  • Lee et al. 2017, targeting CXXC5 by a competing peptide stimulates hair regrowth and wound-induced hair neogenesis (preclinical)

Mechanism in depth

This is the most mechanistically interesting compound in the class and the one with the largest gap between what it does in mice and what anyone knows about humans. Wnt/beta-catenin is the pathway that drives hair follicle induction in development and anagen re-entry in adults. In the resting state, cytoplasmic beta-catenin is captured by a destruction complex — Axin, APC, GSK-3beta and CK1 — phosphorylated, ubiquitinated and degraded. Wnt binding to Frizzled and LRP5/6 recruits Dishevelled, which disassembles that destruction complex, so beta-catenin accumulates, enters the nucleus and partners with TCF/LEF to transcribe the anagen programme. CXXC5 is a negative regulator that binds the PDZ domain of Dishevelled and prevents it from doing that. Choi's group at Yonsei reasoned that if CXXC5 is the brake, occupying Dishevelled with a decoy should release it. PTD-DBM is exactly that: the Dishevelled-binding motif of CXXC5 itself, fused to a protein transduction domain so it can get inside cells, acting as a competitive decoy that displaces endogenous CXXC5 from Dvl. In mice this produced hair regrowth and — the result that made the paper notable — wound-induced hair follicle neogenesis, meaning entirely new follicles forming in healed skin. That is a genuinely rare finding; adult mammals essentially do not make new follicles. Combining PTD-DBM with valproic acid, which inhibits GSK-3beta and therefore activates Wnt upstream, was more effective than either alone. None of this has been shown in a human being. And there is a serious reason to be careful: Wnt/beta-catenin is a canonical oncogenic pathway. Constitutive beta-catenin activation causes pilomatricomas and trichofolliculomas in skin, and APC and beta-catenin mutations are foundational in colorectal cancer. Chronically de-repressing Wnt in human scalp skin is not a risk anyone has quantified.

What usually goes wrong

The honest headline is that you are self-experimenting with an unvalidated research chemical from vendors with no assay standards, at a dose derived by analogy from mice, in a delivery vehicle nobody has characterised. There is no human dose. There is no human safety data. Community protocols reconstituting 5-10 mg into 5-10 mL and applying 1 mL daily are guesses that got repeated until they sounded like guidance. The specific things to watch: scalp irritation from propylene glycol or ethanol vehicles, which is common and usually the vehicle rather than the peptide; and any new, changing or bleeding lesion on the treated scalp, which in the context of chronic Wnt de-repression you should get looked at rather than watched. Also, vendor quality varies enormously for a construct this complex — a fusion peptide is much harder to synthesise correctly than a tripeptide, and there is no way to verify what you received.

Bloodwork worth running

MarkerWhenWhy it matters
Full blood count and liver function testsBaseline and at 3 months if you are running topical valproic acid alongside this.Only relevant if you are following the published mouse protocol and adding valproic acid. Valproate is hepatotoxic, causes thrombocytopenia and, rarely, pancreatitis. Topical valproate exposure is small but people apply it liberally to the scalp for months.Act if: Any new ALT rise above 1.5x the upper limit of normal, or platelets falling below 150, means stop the valproate.

Pharmacokinetics

Metabolism
Not characterised. Assume rapid proteolysis.
Elimination
Not characterised.

Receptor targets

  • Dishevelled PDZ domain — Not published as a Kd

    Competitive occupancy displacing endogenous CXXC5, releasing the brake on Wnt signal transduction.

  • CXXC5 (indirectly, by displacement) — Not published

    CXXC5 can no longer inhibit Dishevelled, so beta-catenin accumulates.

  • Beta-catenin / TCF-LEF transcription (downstream) — Indirect

    Anagen induction, dermal papilla activation and, in mouse wound models, follicle neogenesis.

What to expect, and when

In mice, visible regrowth over three to four weeks of daily application. In humans, unknown — but any real follicular response is governed by the hair cycle, so nothing meaningful could be assessed before three months and six is more realistic. Anyone reporting results at four weeks is reporting shedding changes at best.

Stacking and comparisons

Valproic acid is the published combination and it is the one people copy. Understand what you are doing: valproate inhibits GSK-3beta, which prevents beta-catenin phosphorylation and degradation, so it activates Wnt from a different direction. It is also a teratogen with one of the clearest dose-response relationships in obstetric pharmacology — neural tube defects, and a substantial reduction in childhood IQ after in-utero exposure. Anyone who could become pregnant should not be handling topical valproate solutions, and that is a real statement rather than a legal one. Minoxidil is mechanistically unrelated, which means no overlap and no interaction data. Combining PTD-DBM with microneedling has a real rationale — wound-induced neogenesis was the headline mouse result and needling creates the wound signal — but that also means you are pushing a growth pathway in injured skin, which is precisely when you should be most careful about undiagnosed lesions.

Against finasteride and minoxidil, this has zero human data and those have decades of randomised trials. Nobody should be substituting it for either. Against other experimental hair peptides in this class, PTD-DBM has by far the most interesting preclinical result — wound-induced follicle neogenesis is a different order of claim from prolonging anagen — and by far the least translation. Against zinc thymulin, zinc thymulin has at least been applied to human heads in a study; PTD-DBM has not. The honest positioning is that this is the compound to watch, not the compound to use.

Rough cost

$60–$250/month. Research-chemical vendors price 5-10 mg vials at roughly $40-120, and community protocols consume one to two vials a month. Wide range because vendor pricing and purity are both unstandardised. Market observation, not a sourced pricing study.

Genuinely uncertain

  • The exact peptide sequence of PTD-DBM is in the Lee 2017 paper but I did not resolve it in this session and will not reproduce it from memory.
  • No molecular weight is stated in the Core record and I could not verify one.
  • There are no human trials of any kind, no regulatory filings and no published human safety data.
  • The wound-induced hair follicle neogenesis result has not been independently reproduced, in mice or anywhere else, as far as I could establish.
  • No delivery study exists for human scalp. The mouse data used mouse skin, which is not a valid permeability model for human scalp.
  • The oncogenic risk of chronic topical Wnt de-repression in human skin is entirely unquantified. The pathway biology makes it a legitimate concern rather than a documented harm.
  • Vendor material is unassayed and a fusion construct is synthetically demanding, so there is no assurance that what is sold is what was studied.

Papers