Valproic Acid (Topical Hair)

Valproic acid (2-propylpentanoic acid; CAS 99-66-1; molecular formula C8H16O2; molecular weight 144.21) is a branched short-chain fatty acid in widespread clinical use as the antiepileptic and mood-stabilizer Depakote (sodium valproate; KDC-MN; sodium-valproate). The systemic monograph for sodium valproate is published separately. The topical use of valproic acid for hair regrowth is the subject of this monograph and represents a research-application of the same chemical entity. The pharmacological argument for topical valproic acid in hair is derived from the histone deacetylase inhibitor activity of the compound and the dependence of canonical Wnt/beta-catenin signaling on histone acetylation at Wnt target gene promoters; HDAC inhibition increases Wnt target gene expression and promotes anagen-phase hair follicle activity. Korean academic groups (notably Yonsei University, with the same investigator group developing the PTD-DBM peptide; KDC-MN-1347) have published case-series and small randomized trial data on topical 8.3 percent valproic acid solution for androgenetic alopecia, reporting hair count and density improvements over 24 weeks at frequencies suggestive of meaningful efficacy. The combination with topical PTD-DBM has been studied as a synergistic Wnt-activating regimen with reported additive efficacy in ex vivo and in vivo models. Topical valproic acid is not FDA-approved for any indication; it is compounded by specialty pharmacies for off-label hair use. The systemic safety considerations of valproic acid (hepatotoxicity, teratogenicity, neural tube defects) are substantially mitigated in topical use owing to the extensive first-pass metabolism if absorbed and the limited cumulative dose, but pregnancy contraindication should be observed. Reconstitution into a topical solution typically uses ethanol, propylene glycol, and water; the 8.3 percent (50 mg/mL) solution is the most-studied concentration.