Important aspects about minoxidil
Minoxidil is a modifier of the biological response as it acts by inhibiting the regressive course of hair in Androgenetic Alopecia (AGA). It is an agonist of potassium channels and nitric oxide, thus a vasodilator. It was initially approved as an antihypertensive drug, and it was observed that one of its side effects was hypertrichosis (increased hair growth). It started to be used topically for the control of AGA and other types of alopecia.
After many years of experience, initiated by Zapacosta in 1980, conclusions have been established regarding the use of minoxidil:
- The ideal concentration is 2% to 5% in a hydroalcoholic solution.
- The appropriate dosage is 1 ml twice a day or 2 ml per night.
- Its effects appear in 30% of users and become evident after 4-6 months, optimizing after a year of treatment. The figure increases when it comes to women.
- Discontinuation of treatment results in regression of beneficial effects after 2-4 months.
- Women achieve a better response to minoxidil than men.
- It works better in incipient alopecias (Hamilton grades II-III) or those with less than 10 years of evolution.
Among its possible adverse reactions are:
- Contact dermatitis (allergic or irritant), which may increase when associated with retinoic acid.
- Development of dark circles.
- Hypertrichosis in undesirable areas that may have had contact with minoxidil, for example, the forehead.
- Hypo or hypertension and vascular effects are exceptional.
- Its indication during pregnancy is not well established, although hair loss during this stage is rare.
- Headaches are rare.
Despite the possible adverse reactions described earlier, as a general rule, minoxidil is well-tolerated by the majority of users when applied correctly. Minoxidil works by increasing the thickness of the hair shaft, transforming miniaturized hair (vellus) into terminal hair, and reducing the percentage of follicles in the telogen phase. The exact reason for these changes is not well-established. The active ingredient is not minoxidil itself but its metabolite, minoxidil sulfate, which is produced by sulfotransferase action. Various experimental studies have demonstrated that minoxidil acts at multiple levels:
- Stimulates the proliferation and differentiation of follicular keratinocytes, allowing the extension of the anagen phase.
- Acts synergistically on lymphocytes, fibroblasts, epidermal cells, and mesenchymal cells of the dermal papilla.
- Does not have effects on androgen metabolism.
The use of minoxidil reduces post-surgical effluvium (shock loss) that sometimes occurs after a transplant and shortens the time needed for the grafts to start growing in a significant number of patients.
What is the Dread Shed?
It is the famous fear of temporary hair loss (shedding) that almost always occurs at the beginning of treatment with the drugs. Between 3 and 6 weeks after starting Minoxidil treatment, hair loss may increase due to the medication’s effect. Minoxidil causes old and weak hair to fall out so that new hairs can grow. This phenomenon is usually experienced in the initial stage by almost all users and is seen as a positive sign of the treatment.
Combination therapy of Minoxidil with Finasteride has been shown to be much more effective in treating AGA than the isolated use of the product.
Dr. Couto recommends applying 1 ml with a dropper, not a spray, distributed over the scalp in the areas at risk of hair loss, with dry hair, in the morning and evening, followed by a gentle massage. Contact of the product with the hair shaft does not provide any benefit and can affect hair aesthetics. Applying a drop every 2 or 3 cm is sufficient.
The foam presentation facilitates application and reduces undesired effects on the hair.
