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 hair loss a lot more than I care to admit. And before you ask, yes—my haircare routine is up to par. Am I 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 potent active ingredient, I like to get all the facts.
What is Minoxidil?
A topical serum developed initially as an oral medication for blood pressure that promotes hair growth, thickness, and strength.
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.
- Type of ingredient: Topical treatment for hair growth
- Main benefits: Encourages growth, strengthens strands, stimulates the hair follicle
- Who should use it: In general, anyone with who is concerned about hair loss can use minoxidil. It is not recommended for pregnant individuals.
- How often can you use it: Apply as directed on the packaging to damp hair. You should see results in two to three months with regular use.
- Works well with: Vitamin D
- Don’t use with: Over-the-counter hair dye and other potential irritants
What Is Minoxidil?
A quick Google search will tell you that minoxidil is also an oral medication for blood pressure—which is 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 the treatment of blood pressure, the curious side effect of hair growth was noted.” After a few decades of research, the FDA approved topical minoxidil to treat male hair loss (and thus, Rogaine was born), and then later, for female hair loss as well.
Today, you can find it on shelves in both 2 percent and 5 percent 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 those experiencing hair loss,” explains Samantha Fisher, a Florida-based dermatologist. “Minoxidil can increase the density and thickness of hair.”
Benefits of Minoxidil for Hair
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, supported by recent data suggests that minoxidil increases a specific enzyme (called ATP) in the hair follicle, extending its growth phase (scientifically called the anagen phase). It is also thought to enlarge hair follicles that have shrunken due to hormonal changes.
- Stimulates hair growth: Everyone is different, of course, so results vary, but generally speaking, “in approximately 60-70 percent of patients, hair density will generally begin to stabilize two to three months into treatment, with fewer and fewer hairs being lost each day,” Edhegard says. “Around months six to eight, an increase in density will begin to occur in 40-50 percent of patients, [and] this will continue over the treatment period to each person’s maximum.” In order to keep seeing the results, you have to continue treatment.
- Increases hair thickness and density: In addition to stimulating hair growth and quelling a receding hairline, minoxidil increases hair density and thickness so that strands grow back fuller and healthier.
- Works for most hair types: Generally speaking, minoxidil is safe for all hair types, including natural hair, although those with color-treated hair may experience more irritation. Minoxidil is less effective on certain types of hair loss, such as forms of scarring alopecia that are more common among Black women.
Hair Type Considerations
“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.”
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 expected—although less common if you’re using the 2 percent strength rather than the 5 percent.
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 usual. “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.”
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," she says.
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 to maintain.
How to Use Minoxidil for Hair
Unless you are pregnant or trying to become pregnant, minoxidil should be safe for you to use. Of course, the OG minoxidil product is Rogaine, and there are versions oriented toward women formulated with 2 percent and 5 percent of the ingredient. Recently, a chicer, more millennial version hit the market called Hers, which offers hair regrowth drops with 2 percent minoxidil. While the products are very similar, Hers is a tiny bit cheaper and has an overall more pleasant look. Rogaine is more widely available at pharmacies and on Amazon, while Hers must be ordered directly from the brand online.
Directions will vary depending on the product; most serums are topically applied. For a product like Hers, follow these steps:
- Apply about 1 ml of product to the scalp on damp or dry hair
- Do not wash out for at least four hours
- Repeat twice a day
Suchonwanit P, Thammarucha S, Leerunyakul K. Minoxidil and its use in hair disorders: a review. Drug Des Devel Ther. 2019;13:2777-2786. doi:10.2147/DDDT.S214907
Goren A, Naccarato T, Situm M, Kovacevic M, Lotti T, McCoy J. Mechanism of action of minoxidil in the treatment of androgenetic alopecia is likely mediated by mitochondrial adenosine triphosphate synthase-induced stem cell differentiation. J Biol Regul Homeost Agents. 2017;31(4):1049-1053.
Harvard Health Publishing. Treating female pattern hair loss. Updated August 31, 2020.