Rogaine, the brand name for minoxidil, was the first FDA approved medication for the treatment of hair loss. Rogaine is a topical solution that is applied directly to the scalp. It can now be purchased without a prescription and in generic formulations in concentrations of 5% (for men) and 2% (for women).
Rogaine was developed from the oral blood pressure medication minoxidil (Loniten). Minoxidil taken orally has potential serious side effects on the heart and circulatory system and is used only when other blood pressure medications have been unsuccessful. It was observed that patients who were taking minoxidil began growing body hair and it was reasoned that applying minoxidil directly to a bald scalp might cause hair to grow in this area as well. Studies showed that this was indeed the case, although the growth was generally modest.
The original studies on Rogaine were performed on the crown, so there is a misconception that it only works in this area. Although minoxidil usually works best in the crown, it also works to a lesser degree in other areas, such as the front of the scalp, as long as there is some fine (miniaturized) hair in the area. It does not work when the area is totally bald. The greatest benefit from the medication is seen from 5 months to 2 years, with a gradual decrease in effectiveness after that. Those using minoxidil long-term will continue to lose hair, but at a somewhat slower rate.
Mechanism of Action
Minoxidil increases the duration of the hair follicle growth cycle (called anagen). This improves the quality of the hair by increasing the diameter and length of fine (miniaturized) hair. It can also induce a new anagen cycle to begin. Minoxidil is a direct stimulator of follicular growth (via VEGF and prostaglandin synthetase) and also stimulates the proliferation of dermal papilla cells. Unlike finasteride, its effects are not related to androgens. The simultaneous use of minoxidil and finasteride (which directly inhibits the formation of DHT) may have some synergistic benefit in the treatment of hair loss, although finasteride is significantly more effective.
New research has shown that minoxidil exerts its effect on the hair follicle by opening adenosine-sensitive potassium channels in the dermal papilla of the hair follicle. Minoxidil may also act on dermal papilla cells by phosphorylating Erk and Akt, chemicals involved in sending cellular signals for gene expression and cell division, and by increasing the regular gene Bcl-2:Bax ratio. Another mechanism is that it may up-regulate adenosine, which in turn is capable of inducing several hair growth-related genes, such as FGF7 mentioned above, that was shown to be successful as a hair growth inducer.
Minoxidil should be applied to the scalp once or twice a day. The medication only works if it is in direct contact with the scalp (not the hair) and only works in areas where it is applied. Therefore, it is important to use the medication in the front part of the scalp if this is an area of thinning.
The 5% formulation is more effective than the 2% solution, but contains propylene glycol, a compound that can irritate the scalp and can make the hair feel sticky and difficult to manage. If this is a problem, one should consider using the 5% solution at bedtime and the 2% solution (which is alcohol based and less sticky) in the morning. When using minoxidil, it may take 6-12 months before any results are seen. The majority of patients who see an effect from minoxidil experience a delay, or decrease, in the rate of hair loss. The drug also serves to thicken already existing hair, but most patients who do have results, grow only short, thin fuzz. It will not grow any new hair on a bald scalp.
Rogaine Foam is a form of 5% Minoxidil in a glycerin and alcohol base. The foam technology is a convenient way of delivering minoxidil to the scalp without the sticky and often irritating effects of propylene glycol, the delivery compound used in the original 5% solution. When released from the canister, the new product seems like a shaving foam, but it rapidly “melts” when it reaches skin temperature. Applying Rogaine as a foam allows convenient application to the scalp without dripping or running down the forehead or neck, and without leaving a sticky residue in the hair. However, many patients find this formulation more difficult to apply directly to the scalp – where the medication actually works.
Once a day topical use of Rogaine (topical minoxidil 2% and 5%) seems to be almost as effective as using it twice a day. The reason is, that although minoxidil has a relatively short half-life of several hours when given orally, when topically applied, it has a half-life of 22 hours in the skin. This suggests that once a day dosing is a reasonable option. It is important to realize that Pfizer, the company that now makes Rogaine, specifically states that it will be less effective if used only once a day.
If minoxidil is discontinued, the effects of the drug wear off within three months and the previous pattern of hair loss resumes. When minoxidil is restarted, one generally does not regain the hair that was lost, so it is best not to stop and start the mediation, but to use it regularly.
Minoxidil has been prescribed (off-label) in conjunction with other medications, such as topical retinoic acid (Retin-A), to enhance its penetration into the skin and thus increase its effectiveness. This combination of medications can increase the absorption of minoxidil into the bloodstream and may increase the risk of potential side effects, including changes in blood pressure and scalp irritation. It is important to use combination therapy under the supervision of a physician.
Use in Women
Both the 2% solution and 5% foam formulations of minoxidil are approved for use in women. Women are generally more sensitive to the side effects of minoxidil in decreasing blood pressure (hypotension) and may get light-headed from the medication. Women also have an increased risk of developing allergic skin reactions (contact dermatitis).
An annoying local reaction that women sometimes get from topical minoxidil is the development of facial hair. Although the facial hair slowly resolves when the medication is discontinued, at times the hair may need to be removed. Carefully trying to avoid the medication dripping down onto the temples and forehead seems to reduce, but not totally prevent, this problem. There is a significantly greater incidence of these side effects if the 5% solution is used, especially if applied twice a day.
Dr. Bernstein Answers: Which Is Better, Rogaine Foam Or Liquid?
In this audio clip, Dr. Bernstein discusses the different types of Rogaine. Click here to listen to the audio clip.
- Messenger and Rundegren. Br J Dermatol 2004; 150: 186-94 [↩]
- Han JH et al. J Dermatol Sci 2004; 34:91-98 [↩]