Minoxidil (Oral)

Potassium ATP channel opener that causes arteriolar vasodilation via relaxation of vascular smooth muscle. Originally a potent antihypertensive. At low oral doses, systemic vasodilation increases perfusion to hair follicles, prolongs anagen phase, and upregulates VEGF expression in dermal papilla cells. The follicular effects are the same mechanism as topical minoxidil but delivered systemically at lower concentrations.

Half-life

4.2 hours

Bioavailability

~90% (oral)

Route

oral

Evidence tier

T2 — Single-RCT or mechanistic

Optimization pillars

recovery

References

3 peer-reviewed

Dose ranges

Three tiers ordered by aggressiveness. Tier chips on every OPTIMIZE intervention let you filter the catalog by your evidence tolerance.

conservative

0.625–1.25 mg/day

Low-dose hair growth

moderate

2.5 mg/day

Standard low-dose oral minoxidil

aggressive

5 mg/day

Higher hair loss dosing

Monitoring

creatinine
egfr
hematocrit
hemoglobin
hs-crp

Contraindications

pheochromocytoma
severe-renal-impairment
pulmonary-hypertension
pericardial-effusion-history

References

PMID:33247602Low-dose oral minoxidil for hair loss: a systematic review — Int J Dermatol, 2020
PMID:31046187Oral minoxidil treatment for hair loss: a review of efficacy and safety — J Am Acad Dermatol, 2019
PMID:35871389Systemic low-dose oral minoxidil 1.25 mg for female pattern hair loss — Australas J Dermatol, 2022

Notes

Oral minoxidil at low doses is the dermatology community open secret that became mainstream around 2020. Topical minoxidil works but has compliance problems. Greasy residue, scalp irritation, twice-daily application that most people eventually abandon. Oral dosing at 1.25-2.5mg eliminates every compliance barrier while providing systemic delivery to every follicle simultaneously, including areas topical formulations miss. Tier 2 because the safety data at these ultra-low doses is still being established by retrospective studies and small prospective trials. The antihypertensive era used 10-40mg and caused fluid retention and pericardial effusions. At 2.5mg those risks are dramatically lower but not zero. Monitor for peripheral edema and tachycardia. The compound works. The question is whether the systemic exposure trade-off is worth it versus topical-only approaches.

This is not medical advice

Discuss with a licensed clinician before starting, stopping, or changing any compound. This page documents what the research literature describes — it is not a prescription.

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