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Oral Minoxidil

Metabolicprescriptionoral · inferred

Potassium channel opener originally approved as an oral antihypertensive (Loniten) and now widely used off-label at low doses (0.625-5 mg/day) for androgenetic alopecia and other hair-loss conditions. Works systemically via sulfotransferase activation to minoxidil sulfate, prolonging anagen and increasing follicular vascularity. Higher efficacy than topical in many patients but carries antihypertensive side effects: hypertrichosis, fluid retention, tachycardia, and rare pericardial effusion at higher doses. Distinct from the topical 2-5% formulation.

Projected serum levels — 2.5 mg, once daily

Oral Minoxidil
Oral Minoxidil modeled serum levels, 2.5 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 0.63 1.3 1.9 2.5 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 2.5 mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 2.1 mg, trough ≈ 0.048 mg body load. Population-based estimate over 15 days for a 2.5 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Metabolic
Route modeled
Oral
Model confidence
inferred
Half-life
4.2 h
Common dose
2.5 mg
Suggested maximum
10 mg/day
Reference dose range
1.3–10 mg (single dose)
Suggested cadence
once daily
Validated against
10 mg oral — Cmax 0.14 mg/L at 1 h

Documented interactions

  • moderate
    Carbamazepine (Tegretol) + Oral Minoxidil CYP induction

    Carbamazepine (Tegretol) inducer of UGT predicted to change Oral Minoxidil AUC by ~0.67x

  • moderate
    Phenytoin (Dilantin) + Oral Minoxidil CYP induction

    Phenytoin (Dilantin) inducer of UGT predicted to change Oral Minoxidil AUC by ~0.62x

  • moderate
    Valproic Acid / Divalproex (Depakote) + Oral Minoxidil CYP inhibition

    Valproic Acid / Divalproex (Depakote) reversible_inhibitor of UGT predicted to change Oral Minoxidil AUC by ~1.78x

Serum checks 4 modeled interaction pairings for oral minoxidil across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Efficacy and Safety of Oral Minoxidil 5 mg Once Daily in the Treatment of Male Patients With Androgenetic Alopecia Panchaprateep R et al. · Drug Design, Development and Therapy, 2020 DOI

    Prospective 24-week study of 5 mg oral minoxidil daily in 30 men with AGA showed significant increases in total and terminal hair counts with generally mild adverse effects, supporting low-dose oral use.

  2. Treatment of male androgenetic alopecia with oral minoxidil: a case report Sinclair RD · International Journal of Trichology, 2018 DOI

    Pioneering case report from Sinclair introducing low-dose (0.25-5 mg) oral minoxidil as an alternative to topical therapy for AGA, catalyzing widespread off-label adoption.

  3. Low-dose oral minoxidil for hair loss: A systematic review Randolph M et al. · Journal of the American Academy of Dermatology, 2021 DOI

    Systematic review of 17 studies (634 patients) documenting efficacy of 0.25-5 mg/day oral minoxidil across AGA, alopecia areata, and traction alopecia, with hypertrichosis as most common side effect.

3 published studies referenced in the app, each with a plain-language summary.