Oral minoxidil

Low-dose oral minoxidil (known as LDOM) is the same active ingredient as topical minoxidil, but taken orally at far lower doses than those originally used as an antihypertensive. It is used off-label to treat androgenetic alopecia and other forms of hair loss.

• Male and female androgenetic alopecia (off-label use).
• Other selected types of hair loss, at the physician's discretion.
• An alternative when topical minoxidil is not tolerated or its application is inconvenient.

Minoxidil is a vasodilator that acts as a potassium-channel opener. At the follicle it prolongs the growth (anagen) phase and increases hair calibre. Taken orally, it reaches the follicle systemically, which explains both its efficacy and some of its effects, such as increased body hair.

It is recommended to start at a low dose and titrate gradually. Typical hair-loss ranges are 0.25-2.5 mg/day in women and 1.25-5 mg/day in men, adjusting according to tolerance and response. First results usually appear from 3-6 months, and the benefit is maintained for as long as treatment continues.

The most frequently reported adverse effects are:

• Hypertrichosis (increased facial and body hair), the most common.
• Fluid retention and oedema.
• Tachycardia or palpitations.
• Dizziness from a drop in blood pressure.
• Rarely, pericardial effusion (uncommon; re-evaluate if breathlessness, oedema or chest pain occur).

It usually requires a prior cardiovascular assessment and follow-up.

• Phaeochromocytoma.
• Uncontrolled cardiovascular disease; caution with a history of pericarditis or pericardial effusion.
• Hypersensitivity to the active substance.
• Pregnancy and breastfeeding (insufficient data).

It is not recommended during pregnancy or breastfeeding due to insufficient safety data. In women of childbearing age it should be assessed individually and with adequate contraception.

It should be used with caution alongside other drugs that lower blood pressure, because of the risk of hypotension. Combining it with other vasodilators or with fluid-retaining drugs requires medical supervision.

Level of evidence: growing. In recent years many studies have supported the efficacy and safety of low-dose oral minoxidil in hair loss, although its use remains off-label. The evidence comes mainly from large case series and observational studies. A 2025 international modified-Delphi consensus now guides the initiation and dosing of low-dose oral minoxidil for hair loss.