Minoxidil

Minoxidil, sold under the brand names Loniten and Rogaine among others, is a medication used for the treatment of high blood pressure and hair loss. It may also be used off-label to promote beard growth and treat nail problems. The drug promotes hair growth, but its effects are fully reversible and it does not slow or prevent hair loss. It is available as a

Minoxidil, sold under the brand names Loniten and Rogaine among others, is a medication used for the treatment of high blood pressure and hair loss.[7][8][9][2] It may also be used off-label to promote beard growth[17][18] and treat nail problems.[19][20] The drug promotes hair growth, but its effects are fully reversible and it does not slow or prevent hair loss.[2] It is available as a generic medication by prescription in oral tablet form and over-the-counter as a topical liquid or foam.[10][11][21][22] Oral minoxidil is used at high doses to treat high blood pressure and at low doses to treat hair loss, while topical minoxidil is used exclusively for hair loss and related indications.[23][13] Extended-release oral minoxidil[24][25][26] and sublingual minoxidil formulations for hair loss are also being studied and developed.[27][28]

Side effects of oral minoxidil may include low blood pressure, water retention and edema, salt retention, rapid heartbeat, dizziness, lightheadedness, excessive hair growth, and temporary hair shedding, among others.[23][13] Adverse effects of topical minoxidil include skin irritation, itching, dandruff, and temporary hair shedding, among others.[4] Rare but serious adverse effects of oral minoxidil include pericardial effusion, pleural effusion, cardiac tamponade, other cardiovascular complications, and pseudoacromegaly, among others.[23][29][30][31] Minoxidil is a prodrug of minoxidil sulfate, which acts as a KATP potassium channel opener to widen blood vessels and increase hair growth.[28][13][32][33][34] The effects of minoxidil are dose-dependently similar to the symptoms of Cantú syndrome.[13][32][33]

Minoxidil was discovered in 1963 and was introduced for treatment of high blood pressure in 1979.[35][36] It was unexpectedly found to cause hair growth in 1971, resulting in it being repurposed for treatment of hair loss and approved in topical form for this use in 1988.[35] Topical minoxidil became available over-the-counter in 1996.[35] Low-dose oral minoxidil (LDOM) emerged for treatment of hair loss in 2015[37][38] and dramatically increased in popularity starting in 2022.[13][29][39][37] Extended-release oral minoxidil and sublingual minoxidil were developed in the 2020s for hair loss and are in late-stage trials.[28][24][27] Aside from its use in humans, minoxidil is extremely toxic to cats and dogs even in small amounts.[40][41]

Medical uses

High blood pressure

Minoxidil, when used for hypertension, is generally reserved for use in severe hypertension patients who do not respond to at least two agents and a diuretic.[42] Minoxidil is also generally administered with a loop diuretic to prevent sodium retention and potassium retention.[42] It may also cause a reflex tachycardia and thus is prescribed with a beta blocker.[42]

Hair loss

Minoxidil is used for the treatment of hair loss.[2][3][43] It is mainly used topically, but in more recent years, it also being used at low doses orally and to a lesser extent sublingually.[2][28][3] The drug is effective in helping promote hair growth in both men and women with androgenic alopecia (androgen-dependent pattern hair loss).[43] It works by increasing hair counts as well as by thickening individual hair follicles.[2][28][44] Minoxidil is less effective when the area of hair loss is large. In addition, its effectiveness has largely been demonstrated in younger men who have experienced hair loss for less than 5 years. Minoxidil use is indicated for central (vertex) hair loss only.[45]

Minoxidil must be used indefinitely for continued support of existing hair follicles and the maintenance of any experienced hair regrowth.[8][9] Its benefits are tangible but fully reversible, with discontinuation following long-term treatment resulting in rapid hair loss and similar hair density as placebo at 24 weeks post-discontinuation.[2] As such, minoxidil does not appear to slow or prevent hair loss.[2]

Low-dose oral minoxidil (LDOM) is used off-label against hair loss and to promote hair regrowth.[37] Oral minoxidil is an effective and well-tolerated treatment alternative for patients having difficulty with topical formulations.[46][47][48] It is notable in this regard that topical minoxidil for hair loss has very low compliance rates, with almost all users discontinuing it after 1 year of use.[49][50] Consensus statements provide guidance on use of low-dose oral minoxidil for hair loss.[30][51][3] Dosing of low-dose oral minoxidil for hair loss has additionally been reviewed.[52][53][30] Higher doses are more effective for improving hair loss than lower doses, but also come with greater hypertrichosis incidence.[52]

Another option for hair loss treatment is sublingual minoxidil (SLM), which may have improved tolerability with retained efficacy compared to oral minoxidil.[28][54][44]

Minoxidil requires at least 2 to 4 months before the first benefits on hair growth can be observed.[2] Maximal effectiveness occurs after 12 months.[2]

Beard growth

Minoxidil has been studied for enhancement of facial hair or beard growth, including for transgender men.[17][55][56][18]

Nail problems

Minoxidil has been studied in the treatment of onychodystrophy (nail problems).[19][20] It has been assessed in at least 6 clinical studies for this purpose, with the employed formulations including 2 to 5% topical minoxidil and 1.25 to 2.5 mg/day oral minoxidil.[19] The drug has been found to increase the rate of nail growth, improve nail appearance, increase nail strength, and resolve yellow nail discoloration.[19][20]

Available forms

Minoxidil is available in the form of oral tablets, topical solution, topical foam, and topical spray.[4] The tablets include 2.5 and 10 mg forms, the solutions include 2% and 5% forms, and the foam and spray are both 5% concentration.[2][4][23] The topical solutions are formulated with polyethylene glycol (PEG) to enhance absorption of minoxidil.[4] The topical solution is often referred to as minoxidil topical solution (MTS) and the topical foam is known as minoxidil topical foam (MTF).[2]