Minoxidil

Structure: Piperidinopyrimidine derivative. A prodrug for hair growth: follicular sulfotransferase converts it to minoxidil sulphate, the form that opens ATP-sensitive potassium channels. Men whose follicles carry more of this enzyme activity tend to respond better.

Dosage (hair loss):

• Topical: 5% solution or foam, applied to the scalp once or twice daily
• Low-dose oral (off-label): the 2025 international consensus suggests starting men on 2.5 mg/day, with a usual range of 1.25-5 mg/day. Women start lower.
• VDPHL01 (investigational): 8.5 mg extended-release once or twice daily in the male Phase 3 trials. Not approved, not available, and the milligrams do not translate to immediate-release tablets.
• Historic antihypertensive dosing: 10-40 mg/day, always with a beta blocker and a diuretic. Not relevant to hair and not something to copy.

Evidence snapshot:

• 5 mg oral was not superior to 5% topical on hair density over 24 weeks in a double-blind trial in men, and 49% of the oral group grew unwanted body hair (Penha 2024).
• VDPHL01 Study 304: +28.6 (8.5 mg once daily) and +36.4 (twice daily) non-vellus hairs/cm² at six months vs +6.6 on placebo. Company-reported topline, not yet peer reviewed.

Key Notes:

• Works regardless of the androgen. Because it ignores DHT, minoxidil is the hair option that still works on DHT-derived compounds like Masteron and Anavar, where finasteride has nothing to block.
• Pairs with Finasteride. One removes the DHT signal, the other pushes the follicle to grow. Combination evidence is mostly with topical minoxidil.
• Expect a shed in the first 2-8 weeks as resting hairs are pushed out. It is not a sign of failure.
• Stopping reverses the gain over a few months.
• Avoid compounded or grey-market capsules for oral use. Several of the serious published cases involved capsules containing far more drug than labelled.
• Contraindicated with a history of pericardial effusion or pericarditis, heart failure, or phaeochromocytoma. Use caution with a history of arrhythmia, low blood pressure, or kidney impairment.
• On a cycle: AAS already raise blood pressure and left ventricular mass. No study has tested oral minoxidil in AAS users, so treat the safety data from normal populations as a best case.

Bloodwork Monitoring:

• Resting Heart Rate is the main number to watch on oral minoxidil. In 11 men stepped up to 7.5 mg, average 24-hour heart rate went from 72.6 to 81.3 bpm with no blood pressure change.
• Systolic BP and morning bodyweight for 1-2 weeks before starting, then through the first 12 weeks and after every dose change.
• Ankle or eyelid swelling with flat blood pressure and a rising heart rate points to minoxidil. Swelling with rising blood pressure points more towards Estradiol or Sodium intake.
• Haematocrit is not raised by minoxidil, but fluid retention can dilute it slightly. Do not mistake that for a fix.

What the VDPHL01 Phase 3 trial showed and how oral minoxidil fits with TRT: How much hair oral minoxidil regrew in Phase 3.