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Call it pre-wedding beauty jitters, simply getting older, or having a father who went bald in his twenties (sorry, Dad), but these days I’ve been worrying about hair thinning and loss a lot more than I care to admit. And before you ask, yes—my haircare routine is up to par. Taking care of my scalp? Check. Supplements? Check. Hair still thinning? Check.
All of this got me wondering about Rogaine—or more specifically, minoxidil, its active ingredient. Then, seeing some millennial-targeted ads for newer versions of the OG formula (such as Keeps and Hers) prompted me to investigate. Because before I start using a new product, especially one with such a strong active ingredient, I like to get all the facts. For starters: how does minoxidil work? Do you have to be balding to benefit from it? And are there any negative side effects? I spoke to a slew of experts to find out. Here’s what they had to say.
What Exactly Is Minoxidil?
A quick Google search will tell you that minoxidil is also an oral medication for blood pressure—which is actually how it was first discovered to help with hair growth. “Minoxidil was originally developed in the early 1960s as an oral treatment for high blood pressure, a condition for which it is still, albeit rarely, used,” explains Kim D Edhegard, a Virginia-based dermatologist. “In one of the early trials for treatment of blood pressure, the curious side effect of hair growth was noted.” After a few decades of research, the FDA approved topical minoxidil in the late ‘80’s to treat male hair loss (and thus, Rogaine was born), and in the ‘90s, for female hair loss.
Today, you can find it on shelves in both 2% and 5% formulations, in both liquid (scalp drops) and foam formula. "Minoxidil is a topical medication that is applied to the scalp to stimulate new hair growth in men and women experiencing hair loss,” explains Samantha Fisher, a Florida-based dermatologist. “Minoxidil can increase the density and thickness of hair.”
How Does Minoxidil Work to Re-Grow Hair?
Funny you ask, because scientists can’t quite agree on how minoxidil works to promote hair growth. “Possibly, this hair growth occurs because minoxidil causes increased blood flow to the hair by dilating the blood vessels in the scalp,” explains board-certified dermatologist Divya Shokeen. Another hypothesis, which is supported by recent data, suggests that minoxidil increases a certain enzyme (called ATP) in the hair follicle, which extends its growth phase (scientifically called the anagen phase). It is also though to enlarge hair follicles that have shrunken due to hormonal changes.
However it works, it clearly does work—and there’s plenty of time-tested data to back up its hair growing powers. Everyone is different, of course, so results vary, but generally speaking “in approximately 60-70% of patients, hair density will generally begin to stabilize 2-3 months into treatment, with fewer and fewer hairs being lost each day,” Edhegard says. “Around months 6-8, an increase in density will begin to occur in 40-50% of patients, [and] this will continue over the treatment period to each person’s maximum.”
In other words, in order to keep seeing the results you have to continue treatment, which leads me to…
Are There Any Side Effects?
“One myth that surrounds the use of minoxidil is that it eventually worsens hair loss when stopped,” Edhegard explains. “This is not true; what actually occurs is that the hair will return to the point where it would have been, not back to where it was when treatment started, as untreated hair thinning is a progressive problem.”
So, nothing to worry about there, but it is thought that women are more susceptible than men to other side effects of the medication, particularly lightheadedness and scalp irritation. Minoxidil works at the scalp, not on the hair, which is why irritation can be common—although less common if you’re using the 2% strength, rather than the 5%.
Another possible side effect, especially in women, is that it can stimulate hair growth elsewhere on the body (in unwanted places). “In addition, women may experience facial hair growth as an unwanted side effect at higher potencies,” Fisher says. “Otherwise both women and men minoxidil formulations are exactly the same.” Again, this can be tempered by using a lower percentage of the medication.
Lastly, if you do choose to use minoxidil, don’t be alarmed if at first your hair appears to be falling out faster than normal. “I warn patients that hair shedding initially is normal, as the minoxidil stimulates the resting hairs to cycle into the growing phase,” Fisher explains. “This shedding resolves as the newer, healthier hairs grow in.”
What’s The Best Way for Females to Use Minoxidil?
Unless you are pregnant or trying to become pregnant, minoxidil should be totally safe for you to use. Of course, the OG minoxidil product is Rogaine, and there are female versions that are formulated with 2% and 5% of the ingredient. Recently, a chicer, more millennial version hit the market called Hers, which offers hair regrowth drops with 2% minoxidil.
However, as Brenda Dintiman, another Virginia-based dermatologist, aptly reminds me, “Hair loss on women is complex and can be triggered by stress, changes in your hormones, recent illness, vegetarian or low protein diets, and rapid weight loss.” Therefore, if you’re experiencing serious hair loss, you’d be wise to consult a professional. “A board-certified dermatologist can sort out what’s causing your hair loss and combine topical minoxidil with supplements like vitamin D and dietary recommendations to get your hair glossy, growing and full again.”
For the rest of us, using minoxidil will eventually result in thicker, denser hair—but it will take time to achieve, and you will have to keep up with the treatment in order to maintain.
Next, read our exclusive interview with Tracee Ellis Ross, in which she talks about her new hair product line, her curls, and her journey towards embracing them.