Minoxidil is a vasodilator and originally was exclusively used as an oral drug (Loniten®) to treat high blood pressure. It was, however, discovered to have the interesting side effect of hair growth and reversing baldness, and in the 1980s, Upjohn Corporation produced a topical solution that contained 2% minoxidil to be used to treat baldness and hair loss, under the brand name Rogaine in the United States, and Regaine outside the United States. Treatments usually include a 5% concentration solutions that are designed for men, while the 2% concentration solutions are designed for women.
Mechanism of Action of Minoxidil
The drug seems to exert its maximum effect at the crown of the head. The exact way that minoxidil works is not known.
Cutaneous blood flow is decreased in pattern baldness and minoxidil increases cutaneous blood flow to the scalp, possibly promoting hair growth by this mechanism. However, other vasodilators do not grow hair.
Minoxidil is a “potassium channel agonist.” It contains the chemical structure of Nitric oxide (NO), a blood vessel dilator, and may be a nitric oxide agonist. This may explain Minoxidil’s ability to stimulate hair growth and treat hair loss. Since Minoxidil is a nitric oxide related compound it was suspected to act via activation of Guanylate cyclase, an enzyme involved in vasodilation, however there are no reports of cGMP or PKG activation to date.
Treatment with Minoxidil
The key to using Minoxidil is to begin using it early. The best candidates are those who are thinning but not bald. Those with a higher density of hair at the beginning of treatment are good candidates.
Before applying topical minoxidil, the hair and scalp should be dry. To avoid skin irritation from the alcohol contained in this product, wait at least 30 minutes after washing or shaving before applying this medication to the scalp. The evening dose of minoxidil should be applied at least 30 minutes before bedtime for more complete absorption of minoxidil into the scalp. This will prevent the medication from rubbing onto the pillowcase.
Complete directions for the use of minoxidil are supplied with the medication. Be sure to ask your doctor or pharmacist for these directions, and follow the instructions carefully. Apply 1 mL to the balding areas of the scalp twice daily (in the morning and evening), unless directed to do otherwise by your doctor. The rub-on applicator delivers a 1-mL dose when the bottle is squeezed to fill the top chamber to the black line. The full amount in the chamber should then be applied to the scalp. The total daily dosage should not exceed 2 mL. If fingertips are used to apply the solution, wash your hands afterward to avoid spreading the medication.
Two daily applications for up to four months may be required before evidence of hair regrowth is observed. The onset and degree of hair regrowth may be variable among different patients treated with this medicine. If hair regrowth occurs, two daily applications are necessary for additional and continued hair growth (unless your doctor directs otherwise).
First hair growth may be soft, downy, colorless hair that is barely visible. After further treatment, however, the new hair should be the same color and thickness as the other hair on the scalp.
If one or two applications are missed, restart twice daily applications and return to the usual schedule. Do not attempt to make up for missed doses or use more than 1 mL at a time. Do not use on sunburned skin.
It is important to continue to use minoxidil for the entire time prescribed by your doctor, even if hair growth does not appear within several months.
If there is no hair growth after at least four months or more, consult with your doctor, as this medication may not be effective for you.
Side effects of Minoxidil
As a drug to combat hair loss, the most common side effect is itchy scalp. In some cases Minoxidil may initially cause an increase in hair loss.
There have been cases of allergic reactions to minoxidil or the non-active ingredient propylene glycol which is found in some forms of the topical version, such as Rogaine. Large amounts of minoxidil can cause hypotension, and it has been found that using petroleum jelly or tretinoin on the scalp with minoxidil can cause too much of the drug absorption by the scalp, as can using the drug on sunburned scalps.
If a person uses minoxidil to stop hair loss for a length of time and then stops taking the drug, hair loss will occur again.
Other side effects include:
- acne on the area where it is being used as a topical solution
- headaches and/or lightheadedness
- very low blood pressure
- irregular or fast heart beat
- blurred vision
- chest pain
All the side effects in the above list except for acne may be an indicator that too much of the drug is being used.
It has also been found that the drug can be passed from a mother to a child via breast milk.
- Tell your doctor about unusual or allergic reactions you have had to any medications, especially to minoxidil.
- Before starting treatment with this medication, be sure to tell your doctor if you now have or have ever had heart disease, high blood pressure, or skin problems such as dermatitis or abrasions of or near the area to be treated.
- Because minoxidil contains alcohol, it can cause skin irritation to sensitive areas. You should therefore avoid getting minoxidil in your eyes, nose, or mouth or in areas surrounding scratches or burns.
- Do not apply minoxidil to other areas of the body, because absorption of the drug may be increased and the risk of side effects may become greater. Do not use minoxidil along with other topical medications on your scalp, unless directed to do so by your doctor.
- If treatment is stopped, new hair growth will probably be shed within a few months.
- More frequent applications or use of larger doses (more than 1 mL twice daily) of this medication will not speed up the process of hair growth and may increase the possibility of side effects.
Never the less this drug has proven to be a very effective way to regain hair or to treat hair loss, we recommend you to try first the natural way. There are lots of natural treatments available, including homemade solutions, that will spare you from all the side effects produced by chemicals.
See our posts: “Hair loss, natural ways and homemade remedies in order to achieve hair recovery” and “Natural and Homemade Hair Care” for further info.