- Minoxidil is a "topical" medication, meaning that it is applied to the scalp rather than ingested as a pill.
- The exact mechanism by which minoxidil helps hair growth is not completely understood, but it is known that the drug has many actions including affecting potassium channels in hair follicles, affecting blood flow. Unlike the pill finasteride, minoxidil does not work by affecting androgens.
- Minoxidil helps a proportion of individuals who use it to 'maintain' their hair and in some cases even thicken the hair a bit. Minoxidil does not help everyone.
- Minoxidil mainly helps areas of the scalp where the hair is thinning (miniaturized) - it does not help areas that have already lost hair (bald)
- The medication is available in three main formulations - a 2 % liquid formulation, a 5 % liquid formulation (Extra strength) and a 5 % foam formulation (sold under the name Rogaine foam). 5 % minoxidil is now formally FDA approved for women. Studies have shown it is safe for women (except in pregnancy) and women actually prefer than 5 % foam formulation.
- The manufacturers of minoxidil recommend that the 2 % minoxidil be used twice daily. Studies have shown that women just need to use the minoxidil 5 % foam once daily.
- Minoxidil is applied to the scalp that has been dried. It is very important that the medication be applied to the scalp (rather than the hair). Regardless of whether the liquid or foam is used, the finger tips may be used to gently spread the medication.
- The lotion formulation may be flammable and use of a hair hair dryer (blow dryer) is not recommended.
- Minoxidil is generally quite safe and well tolerated. In the USA, minoxidil in both the 2 % and 5 % strengths are available over the counter and no prescription is required. In Canada, 2 % minoxidil is available without a prescription but the 5 % minoxidil requires a prescription.
The most important side effects of minoxidil include:
1. Irritation of the scalp. The 2 % and 5 % liquid formulations of minoxidil have the potential to irritate the scalp on account of the ingredient propylene glycol. Minoxidil foam (Rogaine foam) does not contain propylene glycol and does not generally irritate the scalp for most users. Rarely, an individual can be allergic to minoxidil.
2. Increased shedding during the first month of use. During the very first month or two of use, some users of minoxidil may experience a slightly increased rate of daily hair shedding. It is important to continue the use of minoxidil in this situation as it is usually not harmful. Old hairs are being shed and new hairs are pushing up from underneath.
3. Hair growth on the face. About 1 out of every 20 women who use minoxidil develop hair growth on the face. This can occur even if minoxidil does not actually 'drip down' and touch the face. The hair growth is reversible if minoxidil is stopped. Women who feel they benefit from minoxidil may choose to remove hair on the face with laser hair removal, electrolysis, waxing and other methods.
4. Other more rare side effects including headaches, dizziness, and heart palpitations, and swollen hands and feet.
Minoxidil needs to be used continuously in order for the benefits to continue. It's completely safe to stop minoxidil at any time, however, any benefits that were seen will be lost over 6-9 months.
It's important to check with your physician when using minoxidil with other medications. Minoxidil can be safely used with oral hair loss medications.
Individuals using minoxidil will start to see an improvement around 6 months.
About 25 % of women who use minoxidil regularly will feel that they have an improvement in their hair. It works best during the early stages of hair loss and for men works best for early stages of balding in the crown.
Patients with heart disease or vascular disease should not use minoxidil. Individuals who are pregnant or trying to become pregnant should not use minoxidil. Individuals with high blood pressure or low blood pressure and patients with irregular heart beats should check with their physician about using minoxidil. Prengant women should also not use minoxidil.