02/10/2023
Oral minoxidil is FDA approved to treat high blood pressure. Doses for this purpose range from 10-40 mg, and common dose-dependent side effects include dizziness, fluid retention, tachycardia, nausea, and hypertrichosis (excessive hair growth on the scalp and body). Due to this serendipitous side effect, which occurs in approximately 80% of individuals, minoxidil was made into a topical preparation for hair growth in the 1980s.
Minoxidil can increase hair thickness and length due to its ability to shorten the resting phase and prolong the growth phase of the hair cycle. When minoxidil is applied to the scalp topically, the hair follicles have to convert it to its active form, minoxidil sulfate, in order for it to help with hair growth. This conversion is dependent on the individual having sufficient sulfotransferase enzymes in their hair follicles, so some individuals may be non-responders to topical minoxidil.
Over the last few decades, dermatologists have trialed the use of low dose oral minoxidil (LDOM) with the aim of improving hair density while limiting adverse side effects. Doses for this purpose range from 0.25 - 5 mg, with titration and max dosages differing for men and women. Its use for hair loss remains “off-label”.
Many people find oral administration more convenient than topical minoxidil, and since it is converted to its active form in the liver, a higher proportion of people will respond to treatment.
While chances of systemic side effects are much lower with topical use, low-dose oral minoxidil (LDOM) also has a good safety profile. In a multicenter study of 1404 patients, only 1.7% of patients discontinued the drug due to adverse effects. Potential adverse effects of LDOM include light-headedness, fluid retention, tachycardia, headache, pedal edema, and insomnia. All adverse side effects improved with dose adjustment or withdrawal of LDOM.
Have you heard about LDOM for hair loss? Leave your questions or comments!
Note: this post is intended as an informational resource only. As always, be sure to consult your health care provider for advice on prescription medications for hair loss.
