Hair loss, be it seasonal shedding, postpartum hair loss or androgenetic alopecia, is incredibly discouraging, which may explain why the market is packed with products that have big (but often empty) promises. Using minoxidil for hair growth is one of the few thin-hair solutions that has the science to back up its efficacy, which is why it continues to be a mainstay for thinning hair.
When it comes to hair growth, minoxidil is in a league of its own. It “remains the benchmark for over-the-counter hair-loss treatments because it has one of the strongest evidence bases of any topical hair-growth ingredient,” says Sejal Shah, a board-certified dermatologist in New York City. “Studies have consistently shown that it can slow hair loss and stimulate new growth in both men and women with hereditary pattern hair loss, making it one of the best-supported non-prescription treatments available.”
Not only that, but minoxidil is approved by the FDA for certain types of pattern hair loss, which sets it apart from shampoos, serums and supplements, which might have promising data behind them, but not the same level of regulatory review, she says. Plus, minoxidil is fairly easy to get and use: “Bonus points: it is accessible and affordable,” says Sandra Oska, a board-certified dermatologist in Los Angeles.
The impact of minoxidil is so profound that it’s the standard that other, newer hair-loss therapies, like exosomes and peptides, are compared to, according to Carmen Castilla, a board-certified dermatologist in New York City. Here’s what to know about this incomparable ingredient.
The benefits of minoxidil for hair growth
Minoxidil helps with hair growth—which is true, but it’s a little simplistic. Part of the appeal of minoxidil “is its ability to target multiple aspects of hair loss rather than a single pathway,” says Dr Castilla.
For one, it can prolong the hair’s growth phase. While the exact mechanism isn’t entirely understood, “it’s thought to prolong the growth (anagen) phase of the hair cycle, transitioning follicles from the resting (telogen) phase into the growth phase,” says Dr Shah. That means your hair prioritises growing over shedding.
It can also bulk up hair follicles. Follicle miniaturisation (which happens in male- and female-pattern baldness or androgenetic alopecia) describes when hormones actually shrink the hair follicles, so the hairs grow thinner and shorter. Minoxidil reverses this, making hair follicles larger again. It also can “increase blood flow around the hair follicles through vasodilation,” says Dr Shah. “The overall result is that more follicles remain actively growing hair and some previously thinning hairs become thicker.”
For that reason, minoxidil tends to be most helpful with androgenetic alopecia, which usually looks like gradual thinning at the crown or around the hairline. But it can also benefit others. “In some situations, I recommend it to patients to help support regrowth after a shedding event, provided the underlying cause is also being addressed,” says Dr Oska. For example, if you’re seeing stress-related shedding after a major life event, you can try minoxidil to help with regrowth—assuming the trigger has been resolved.
The downsides of minoxidil for hair growth
There aren’t many downsides of minoxidil for hair growth, although it can have some mild side effects like scalp irritation, itchiness, dryness or flaking, redness and burning or stinging, per Dr Shah. That’s because “some formulations contain propylene glycol, which can cause irritation,” she explains.
Another drawback? You might notice more shedding when you first start using minoxidil. “This can happen because older hairs are shed as follicles transition into a new growth cycle,” says Dr Shah. “While it can be concerning, it’s often temporary.”
And finally, it’s possible to see hair growth in areas other than your scalp, but that only really occurs if you repeatedly touch your face (or some other skin) when you’re applying it.
How to use minoxidil for hair growth
First, start minoxidil as soon as you notice shedding or hair loss, since it works best if you start it before significant follicle miniaturisation has happened. “Hair loss treatments are much better at keeping the hair on your head versus growing new hair,” says Dr Castilla. “In addition, further into the hair-loss process, hair follicles become less responsive to treatment.” Not only that, but most people will start to see a difference only after four to six months of using it, so the sooner the better.