Minoxidil

Minoxidil, in topical form, is one of the most commonly used treatments for hair loss. Available without a prescription, it comes in concentrations of 2% and 5% in both solution and foam forms. The 5% concentration is recommended for both men and women, as it is more effective than the 2% solution.

Minoxidil promotes hair growth by extending the anagen growth phase, shortening the telogen resting phase, and enlarging miniaturized follicles. Although the exact mechanism is not entirely clear, minoxidil is a vasodilator, and the induction of vascular endothelial growth factor (VEGF) may promote the vascularity and size of dermal papillae, which correlates with hair shaft growth and size.

In a large randomized, double-blind, placebo-controlled study involving 393 men with androgenetic alopecia, 5% minoxidil applied twice daily was significantly more effective than placebo (and 2% minoxidil) in promoting hair regrowth. After 48 weeks of treatment, 57% of men in the 5% minoxidil group experienced hair regrowth, compared to 41% in the 2% minoxidil group and 23% in the placebo group.

Another randomized, double-blind, placebo-controlled study with 381 women demonstrated that both 2% and 5% minoxidil were effective in promoting hair regrowth in women with androgenetic alopecia when compared with placebo.

Minoxidil is generally considered safe and well-tolerated. However, some common side effects include scalp irritation, itching, and dryness. The foam formulation is preferred by some, as it lacks propylene glycol, which can cause irritation in certain individuals.

It is important to note that the effectiveness of minoxidil varies depending on the individual and the severity of their hair loss. It may take several months of consistent use before results are noticeable, and hair regrowth may not occur in all individuals. Additionally, minoxidil must be used continuously to maintain results.

Oral minoxidil has been used for decades to treat high blood pressure. Patients being treated for blood pressure noticed increased hair growth, which led to the development of a topical preparation. However, low-dose oral minoxidil has been used specifically for treating hair loss and is effective in treating androgenetic alopecia, as well as several other types of hair loss.

A recent meta-analysis, including 17 studies with 634 patients, demonstrates that low-dose oral minoxidil can be an effective and well-tolerated alternative for healthy patients who have difficulty with or do not respond adequately to topical formulations. The dose range is from 0.25 mg per day up to 2.5 mg per day. Side effects are generally mild and dose-dependent. The most common side effect is hypertrichosis (increased hair growth outside of the scalp, occurring in 10-20% of patients), but most patients did not find this bothersome enough to stop the medication. Generally, there is no significant change in blood pressure; however, some patients (less than 10%) may experience an increased heart rate, dizziness upon standing, and lower leg swelling. For the appropriate patient, low-dose oral minoxidil can be an effective treatment to promote hair regrowth.