Minoxidil Results After 1 Year: What to Expect

What the 48-week trials actually measured

The largest trial of the 5% solution ran 48 weeks. Olsen and colleagues randomized 393 men aged 18 to 49 to 5% solution (n=157), 2% solution (n=158) or placebo (n=78), applied twice daily [1]. At week 48, 5% was significantly superior to both 2% and placebo on change from baseline in nonvellus hair count, with response occurring earlier than with 2% solution [1]. It was also superior to both on patient ratings of scalp coverage and treatment benefit and on investigator ratings of scalp coverage [1]. More men on 5% reported pruritus and local irritation [1].

In women, Lucky and colleagues ran the matching 48-week trial: 381 women aged 18 to 49, randomized to 5% (n=153), 2% (n=154) or placebo (n=74), twice daily [2]. The 5% solution was superior to placebo on all three primary measures, which were nonvellus hair count and patient and investigator assessments of hair growth and scalp coverage [2]. The 2% solution beat placebo on hair count and investigator assessment but not on patient assessment [2]. 5% was statistically superior to 2% on the patient assessment of treatment benefit at week 48 [2]. More pruritus, irritation and hypertrichosis occurred with 5% than with 2% or placebo [2].

These are group-level hair counts and rating differences. They do not tell you what any one person will see in the mirror at month 12, and this evidence is for the solution. How minoxidil stimulates hair growth is still not well understood [7]. The 5% foam was tested in a 16-week placebo-controlled trial of 352 men, in which it increased hair counts versus placebo (P<.0001); 143 men continued into a 52-week open-label safety phase, and no efficacy data were collected past week 16 [6].

The label's own timeline

The men's 5% solution label directs 1 mL with the dropper twice a day directly onto the scalp in the hair loss area, for the top of the scalp only, and states the product is not intended for frontal baldness or a receding hairline [3]. It says results may occur at 2 months with twice-a-day use and that some men may need to use the product for at least 4 months before seeing results. Using more or more often will not improve results [3].

The women's 5% foam label directs half a capful once daily, says results may occur at 3 months, and says some women may need to use it once daily for at least 6 months before seeing results [4]. It carries the same statement that using more or more often will not improve results [4].

How many people actually respond?

The clearest pooled numbers for a defined regrowth category come from a Cochrane review of treatments for female pattern hair loss: 47 trials with 5290 participants, 17 of which evaluated minoxidil. Pooling six studies, 157 of 593 participants treated with minoxidil (2%, plus one study at 1%) reported a moderate to marked increase in hair regrowth, compared with 77 of 555 on placebo (risk ratio 1.93, 95% CI 1.51 to 2.47) [5]. Investigator-rated assessments in seven studies with 1181 participants pointed the same way (risk ratio 2.35, 95% CI 1.68 to 3.28) [5]. Those figures are for women and mostly for 2% minoxidil. They are not a one-year response rate for 5%.

Each label states plainly that the amount of hair regrowth is different for each person and that the product will not work for everyone [3][4].

Side effects by the one-year mark

In men, 5% solution caused more pruritus and local irritation than 2% [1]. In women, 5% caused more pruritus, irritation and hypertrichosis than 2% or placebo [2]. Foam may be gentler on the scalp: in a 24-week trial of 113 women, 5% foam once daily was noninferior to 2% solution twice daily for hair count and hair width and produced significantly lower local intolerance (P=.046), especially pruritus and dandruff, and the foam vehicle is propylene glycol-free [8][6].

The men's 5% label's stop-use list includes chest pain, rapid heartbeat, faintness or dizziness, sudden unexplained weight gain, swelling of the hands or feet, scalp irritation or redness, and unwanted facial hair growth [3]. The women's foam label carries the same list [4]. Both topical labels include a heart-disease warning [3][4]. Both are for external use only, and both warn that the product is flammable, the foam extremely so [3][4]. The men's 5% solution is labeled for men only [3].

Oral versus topical minoxidil in randomized trials

Two randomized comparisons found no significant difference between oral and topical minoxidil over about six months. A double-blind trial in Brazil randomized 90 men aged 18 to 55 to oral minoxidil 5 mg daily or topical minoxidil 5% twice daily for 24 weeks; 68 completed. Between-group differences were not statistically significant: frontal terminal hair density 3.1 hairs/cm2 (95% CI -18.2 to 21.5; P=.27) and vertex terminal hair density 23.4 hairs/cm2 (95% CI -0.3 to 43.0; P=.09) [9]. A second trial of 65 patients found that both 5% topical solution and oral minoxidil 1 mg/day improved hair diameter over 6 months (P<0.001), with no significant difference between groups [10].

Oral minoxidil tablets (Loniten and generics) are a prescription antihypertensive approved only for severe hypertension, and no oral minoxidil product is FDA-approved for hair loss [11]. The tablet label states that use of minoxidil tablets, in any formulation, to promote hair growth is not an approved indication.