Like finasteride, minoxidil is scientifically proven to improve hair growth and potentially help men with male pattern baldness regrow “lost” hair.
However, there’s some debate online about whether or not minoxidil works on the hairs around the hairline. In the tests used to secure FDA approval, minoxidil was primarily tested on the top of the scalp and crown, resulting in a common belief that it only works on these areas.
Despite this, there’s lots of evidence that minoxidil is effective at promoting hair growth on the entire scalp, including the hairline.
In this guide, we’ll look at the science behind minoxidil to give you a deeper understanding of how it works, why it’s effective and why it’s worth considering (along with finasteride) if you’ve noticed your hairline starting to thin and recede.
Minoxidil is a vasodilator, meaning it’s designed to dilate blood vessels and improve the flow of blood to certain areas of your body.
Although it’s mechanism of action isn’t exactly known, it is believed that when applied topically in the form of a serum or foam, minoxidil interacts with scalp sulfotranferase, which converts it into minoxidil sulfate — which is thought to be the active form of minoxidil.
From there, it shortens your hair’s telogen phase (the phase when the hair is resting and beginning the process of falling out), and pushes it into the anagen phase (the growth phase) prematurely, and even extends the growth period of hair, making your hair grow longer and thicker.
Unlike finasteride, which works by reducing the levels of DHT in your bloodstream, minoxidil has no known effect on your hormones. It’s best to think of minoxidil as a local solution that can help improve your hair growth, while finasteride is designed to shield your follicles from DHT.
One of the most common misconceptions about minoxidil is that it’s only effective on the scalp and crown. Many people are convinced that minoxidil isn’t effective for preventing hair loss around the hairline.
In its early days, before a topical form was developed and became a mainstream hair loss treatment, minoxidil was developed as a treatment for hypertension.
Noticing that oral minoxidil produced hair growth as a noticeable side effect, researchers at Upjohn (the company originally developing the medication) created a topical form to repurpose as a topical hair loss treatment for men suffering from androgenic alopecia.
For new medications to go onto the market, they need to pass through a rigorous trial and testing process to show that they’re not only safe, but also effective.
Upjohn launched large-scale clinical tests of minoxidil throughout the US in the late 1970s, with testing continuing throughout the 80s and 90s. The efficacy side of this testing mostly focused on minoxidil’s effects on hair growth around the scalp and crown.
For example, one study from 1986 focused on the effects of minoxidil on the balding crown. In the study, 53 percent of participants experienced significant hair growth. In short, Upjohn realized that minoxidil worked very effectively, but focused most of its testing on the crown and scalp.
Most other studies of minoxidil have assessed hair growth on the scalp. For example, another study from 2002 tested five percent minoxidil against two percent minoxidil, again by assessing change in hair coverage around the scalp.
A 2014 study with 16 healthy male subjects to study the effects of five percent minoxidil topical foam on other parts of the scalp other than the vertex found that minoxidil was effective in treating hair loss in the frontal scalp as well as the vertex.
For the most part, the claim that minoxidil only works on the scalp and crown of the head comes from this research. It’s not that minoxidil isn’t effective around the hairline (logically, it is) but that there so far hasn’t been extensive research conducted on minoxidil and hairline restoration.
Minoxidil works by improving blood flow to the area in which it’s applied. Apply it to your scalp and it can potentially improve hair density and increase the rate of growth.
As such, there’s no reason minoxidil shouldn’t work for a receding hairline. The hair follicles in your hairline aren’t significantly different from the others on your scalp or crown, meaning that you should still experience the benefits of minoxidil when you apply it to your hairline.
There are also countless anecdotal cases of people with receding hairlines improving growth and increasing thickness by using minoxidil.
However, right now there isn’t much detailed scientific research on the effects of minoxidil on the hairline. As such, it’s best to view minoxidil as something with potential benefits, instead of as a guaranteed way to regrow your hairline.
It’s also worth considering minoxidil in combination with a DHT blocker like finasteride. Studies show that minoxidil and finasteride can have a synergistic effect in preventing hair loss, making the two medications a popular combo for protecting your hairline and scalp from baldness.