Topical Minoxidil Super-Responder Profile: Who Gets the Best Results?

Who the Labels Say Responds

The men's 5% label states that the amount of hair regrowth is different for each person and that the product will not work for all men [1]. The women's 5% foam label carries the same statement for women [2].

The labels also list who should not use the product. The men's label says not to use it if you are under 18, have no family history of hair loss, have sudden or patchy hair loss, do not know the reason for the hair loss, have a scalp that is red, inflamed, infected, irritated or painful, or use other medicines on the scalp [1]. The women's label adds hair loss associated with childbirth [2].

The men's 5% label covers the top of the scalp (vertex) and says it is not intended for frontal baldness or a receding hairline [1].

A 2014 paper on the sulfotransferase assay notes that efficacy of topical minoxidil in the overall population remains relatively low at 30 to 40% [5]. That is a population figure, not a way to identify an exceptional responder beforehand.

Strength: The Largest Measured Difference

In a 48-week double-blind trial of 393 men aged 18 to 49 with androgenetic alopecia, 5% solution (n=157) was significantly superior to 2% solution (n=158) and placebo (n=78) for change in nonvellus hair count, patient rating of scalp coverage and treatment benefit, and investigator rating of scalp coverage [3]. Response occurred earlier with 5% than with 2% [3]. Pruritus and local irritation were more frequent with 5% [3].

In a matching 48-week trial of 381 women aged 18 to 49, 5% solution (n=153) was superior to placebo on all three primary measures. The 2% solution (n=154) beat placebo on hair count and investigator assessment of growth, but not on patient assessment of hair growth. On patient-rated treatment benefit at week 48, 5% was statistically superior to 2% [4].

The Scalp Enzyme That Activates Minoxidil

Minoxidil is converted in the scalp to its active form, minoxidil sulfate, by the enzyme SULT1A1 [5]. In organ-cultured mouse vibrissa follicles, minoxidil sulfate was 14 times more potent than minoxidil at stimulating cysteine incorporation into hair shafts, and blocking sulfation blocked the effect of minoxidil but not of minoxidil sulfate [6].

SULT1A1 and related sulfotransferase genes are expressed in human epithelial tissue, and the expression pattern suggests that one or more of these isoforms may be involved in the cutaneous sulfoconjugation of minoxidil [8].

The prediction data come from a single preliminary study. A retrospective study of a SULT1A1 activity assay in the hair follicle reported 95% sensitivity and 73% specificity in predicting response to minoxidil for androgenetic alopecia, with a larger prospective study described as under way [5].

Who the Trials Enrolled

The trials studied separate groups: 393 men aged 18 to 49 with androgenetic alopecia [3], 381 women aged 18 to 49 [4], 126 men with early male pattern baldness who completed a 12-month trial of 2% and 3% solution [9], and 352 men aged 18 to 49 in a 16-week 5% foam trial that collected no efficacy data past week 16 [10].

Applying It the Way the Labels Describe

The men's 5% solution label directs 1 mL with the dropper twice a day directly onto the scalp in the hair loss area [1]. The women's 5% foam label directs half a capful once daily [2]. Both labels state that using more or more often will not improve results, and that continued use is necessary to increase and keep regrowth, or hair loss will begin again [1][2]. The women's foam label says it is extremely flammable and to avoid fire, flame or smoking during and immediately following application [2].

Microneedling: One Small Trial

A 100-patient randomized study of men with mild to moderate androgenetic alopecia (Norwood III vertex or IV) compared weekly microneedling plus twice-daily 5% minoxidil lotion against 5% minoxidil lotion alone. At 12 weeks, mean hair count change in a 1 cm² target area was 91.4 hairs with microneedling versus 22.2 with minoxidil alone. In the microneedling group 41 patients (82%) reported more than 50% improvement, versus 2 (4.5%) in the minoxidil-only group. Investigators reading global photographs were blinded [7]. It was a pilot study with a 12-week endpoint.

How Long Before You Can Judge the Result

The men's label says results may occur at 2 months with twice-a-day use and that some men may need at least 4 months [1]. The women's label gives 3 months for once-daily use and at least 6 months for some women [2].

The men's label lists no hair regrowth at 4 months as a reason to stop use; the women's 5% foam label lists 6 months [1][2]. Both labels also list chest pain, rapid heartbeat, faintness, dizziness, sudden unexplained weight gain, swelling of the hands or feet, scalp irritation or redness, and unwanted facial hair growth as reasons to stop use [1][2].