Overview of Minoxidil

In androgenic hair loss, DHT causes susceptible hair follicles on the scalp to become smaller, turning the thicker, longer terminal hairs into thinner, shorter vellus hair. Reversing this process was once thought impossible—until minoxidil came along. ⁷⁷ It has also been shown to be an effective treatment for alopecia areata, an inflammatory hair loss condition.

Terminal-type hair growth from vellus – size follicles was an unexpected side effect of minoxidil. It was originally primarily used as an orally-administered high blood pressure treatment drug designed to dilate vessels. ⁷⁷ Determined to be safe and effective, minoxidil (in topical form) is one of two medications approved by the U.S. Food and Drug Administration to treat hair loss, with the brand name (Rogaine®) and generic products sold over-the-counter in many retail locations and through online retailers such as Amazon.com. ¹⁹²

How Is Minoxidil Used?

Minoxidil is applied topically to the scalp to stimulate regrowth of hair, and comes in 2% and 5% concentrations. Original formulations of topical minoxidil combined it with propylene glycol, a common antimicrobial solution used with active pharmaceutical ingredients meant to be applied topically in preservative-free cream, liquid gel, lotion, and ointment forms. ²¹⁶

While treatment must be continued to maintain results, some people report that this can be achieved with application once or twice weekly after using the product for 6-12 months. ²⁰ Readily available forms of minoxidil are used in the following dosages, applied as directed to the scalp where there is thinning hair on top of the head: ¹³

It is often used in conjunction with hair transplant surgery to help maintain existing hair around the implants. Men who find the original topical solution form messy to apply may prefer the newer 5% foam formulation. Although it is only available in the higher concentration, minoxidil foam may actually have fewer side effects because it does not contain propylene glycol, an antibacterial ingredient used in the gel form. ¹⁹²

Although it is not yet approved by the U.S. Food and Drug Administration, minoxidil administered via mesotherapy may be a safe and more effective way to regrow hair than topical minoxidil. In a 12 week clinical trial conducted by two universities in Egypt, 60 women with androgenetic (female pattern) hair loss were randomly assigned to two equal-sized treatment groups. One group was treated topical 2% minoxidil (2 mL/day), while the other group received 0.1 cc injections of 2% minoxidil (for every 2 cm of scalp area) once a week for a month and then once every other week for two months. Testing indicated that while both groups showed decreases in telogen hair percentage and increases in hair growth, the mesotherapy group outcomes were significantly better than the group using topical minoxidil. ²¹⁷

At the cellular level, minoxidil exerts a number of different growth stimulating effects in the hair follicle, including: ^{30, 32, 212}

• Stimulates resting hair follicles into growing mode, increasing the length of time hair is in the anagen phase of its hair growth cycle.
• Significantly increases production of a specific growth factor (VEGF) in dermal papilla cells. VEGF increases the growth of new blood vessels in these cells, stimulating hair growth, increased follicle size, and increased hair diameter.
• Promotes cell division and increased uptake of cysteine, an important amino acid in keratin hair proteins.

Studies in both men and women confirm that minoxidil works in conjunction with the hair cycle. Hair regrowth is noted within eight weeks of use and peaks at sixteen weeks. Results from recent clinical trials on both 2% and 5% minoxidil indicate that hair regrowth is noticeable by eight weeks, and that peak regrowth occurs after 16 weeks.^{3, 20}