Peptides›Cosmetic›Minoxidil

Minoxidil

/ Vasodilator small molecule; ATP-sensitive potassium channel opener

TIER 1 · ClinicalN = 0 · TESTING PENDINGMW 209.30 g·mol⁻¹

ALIAS · Rogaine (trade) · Loniten (trade — oral) · Minoxidil

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Research use onlyAny dose figures below describe what specific cited studies used, reported factually. Nothing on this page is guidance for human use.READ FIRST →

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§ A · Identity

Primary sequence— sequence not captured —

MW · 209.30CLASS · Vasodilator small molecule; ATP-sensitive potassium channel openerCATEGORY · Cosmetic

Tier 1. Oral minoxidil (Loniten) was FDA-approved in 1979 for severe refractory hypertension. Topical minoxidil (Rogaine) was FDA-approved in 1988 for men with androgenetic alopecia and in 1991 for women. Recent off-label use of low-dose oral minoxidil for AGA is supported by a growing randomised-trial literature (Sinclair 2018 and subsequent series) but is not an FDA-approved indication.

§ B · Mechanism of action

Minoxidil is a piperidinopyrimidine prodrug that is sulfated by hepatic and follicular sulfotransferase enzymes (SULT1A1) to the active metabolite minoxidil sulfate, which opens ATP-sensitive potassium (K-ATP) channels in vascular smooth muscle. In hypertension, K-ATP opening hyperpolarises arterial smooth muscle, reducing vascular tone. The hair-growth mechanism is incompletely characterised but appears to involve prolongation of the anagen growth phase, vasodilation in the dermal papilla, and effects on growth factors including VEGF; the requirement for SULT1A1 activation in scalp tissue contributes to the observed inter-individual variability in topical response.

§ C · Human clinical evidence

Tier 1. Phase 3 trials of topical minoxidil 5 percent versus 2 percent in men (Olsen 2002) reported greater hair regrowth with the 5 percent formulation. Multiple randomised trials in women have supported the female AGA indication. Sinclair 2018 reported a randomised trial of low-dose oral minoxidil 0.25 mg/day for female pattern hair loss with measurable benefit; subsequent observational series have extended this to broader AGA populations and dose ranges. Oral minoxidil at antihypertensive doses has decades of clinical use for refractory hypertension.

§ D · Primary literature

PubMed12196747Olsen EA et al. — A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men · Journal of the American Academy of Dermatology · human-phase-3-rctTopical minoxidil 5 percent produced greater hair count and patient-reported hair regrowth than 2 percent or placebo over 48 weeks in men with androgenetic alopecia.Limitations: Surrogate hair-count endpoint; industry-sponsored; 48-week duration.2002

PubMed29231239Sinclair RD et al. — Female pattern hair loss: a pilot study investigating combination therapy with low-dose oral minoxidil and spironolactone · International Journal of Dermatology · human-observationalCombination low-dose oral minoxidil (0.25 mg) with spironolactone (25 mg) was associated with reduced hair shedding and improved Sinclair scale scores at 12 months in 100 women with female pattern hair loss.Limitations: Open-label observational series; no placebo arm; combination therapy precludes attribution to minoxidil alone.2018

§ F · Safety signal

Topical minoxidil commonly produces scalp irritation, contact dermatitis, and unwanted facial or body hair growth; the unwanted-hair effect is dose-dependent and more prominent with the 5 percent formulation. Oral minoxidil at antihypertensive doses (5 to 100 mg/day) carries a black-box warning for pericardial effusion and progression to tamponade and is restricted to refractory hypertension because of fluid retention and reflex tachycardia requiring concomitant diuretic and beta-blocker. Low-dose oral minoxidil for AGA (typically 0.25 to 5 mg/day) has a more favourable cardiovascular profile in published series but is not the labelled use.

§ H · Regulatory status

Regulatory status

FDA status:: FDA-approved
Compounding:: Not eligible for compounding (approved, not in shortage)

§ I · Notable gaps and controversies

The recent rise of low-dose oral minoxidil for AGA outpaces the FDA-labelled indication, and the published evidence base is heterogeneous (single-centre observational series predominate over double-blind RCTs). SULT1A1 enzyme activity in scalp tissue varies between individuals and is one source of the observed variability in topical response; there is no widely available clinical assay for this. Compounded topical minoxidil at concentrations above 5 percent is sold by some pharmacies for AGA without a rigorous trial base supporting the higher concentrations.