The procedure, also known as Blotox, is gaining traction as a sweat-reducing, blow-out–preserving solution to your post-workout hair woes.

Photo: Chaloemphon Wanitcharoentham /

If you frequent workout classes that leave you sweat-drenched (e.g., spin, boot camps, HIIT, and treadmill classes), you're probably familiar with how just one 45-minute session can leave your hair soaking wet. And sometimes dry shampoo simply doesn't cut it.

So what's a girl short on time to do when she loves high-intensity workouts but also wants to preserve her blow-out? Enter Blotox, aka scalp Botox, a treatment some creative dermatologists and plastic surgeons are offering to let their patients have their workouts and their blow-outs, too.

We first heard of the trend from New York City–based dermatologist Dendy Engelman, M.D., in 2015, who reported an influx of women asking for the procedure. But we were a little skeptical. Were women really going to such extremes to protect their blow-outs? So we asked around. The verdict: "It's definitely a trend. There's no question about it," confirmed New York City–based dermatologist Julie Russak, M.D.

Dr. Russak started offering her Blotox services in 2014, when a patient complained that her head was sweating so much after a workout that it was impossible to keep up with washing and styling it. In the months following, Dr. Russak treated at least 20 more women who heard about the procedure through word of mouth. In the five years since, it's become even more mainstream and is now offered at dermatologists' offices across the country. (Want a quick fix? See these easy hairstyles to boost a second-day blow-out!)

Read on for more about the beauty trend.

What is scalp Botox or Blotox exactly?

As you've probably gathered, Blotox involves injecting Botox into the scalp to prevent localized sweating. Yep, the same Botox that is used to smooth wrinkles. This is considered an "off-label" use for the drug, meaning it's not the use it has officially been approved for. But derms have been using the anti-ager for the purpose since practically the beginning. (Related: 5 Uses for Botox That Don't Involve Wrinkles)

"When we first started using Botox, patients who were getting it on the forehead said it was helping with sweating too," explains Soheil Simzar, M.D., a dermatologist based in Los Angeles. Derms have also been performing Botox scalp injections to help with migraines for years, he adds.

And Botox has since been approved by the FDA for use for excessive sweating under the arms, explains Papri Sarkar, M.D., a dermatologist in Brookline, MA. But doctors don't only use it for armpit sweat. "Dermatologists regularly use Botox to successfully decrease sweating in lots of other areas, including the palms, soles, and under the breasts," says Dr. Sarkar.

So, while "off-label" might sound kind of scary, it's not a big deal if you find a physician who is experienced with the particular off-label use you're considering. In this case, that means you'd want to find a doctor who has done Blowtox many times before.

How does scalp Botox work?

On a scientific level, Botox blocks the communication between the nerve and the sweat gland, effectively preventing the glands from working and you from perspiring. "The procedure is quick and simple, taking just 15 minutes in most cases," says Norman Rowe, M.D., a New York City-based board certified plastic surgeon.

Blotox involves extremely superficial injections throughout the scalp using the tiniest needle available (smaller than the size of a hair). Depending on the size of your head (injections are made every square centimeter!) and how bad you usually sweat, a full treatment may require anywhere from 100 to 150 injections per session, explains Dr. Engelman. (Related: Why You Should Treat Your Scalp to a Detox)

Luckily, since the scalp doesn't have many nerve endings, it doesn't hurt as much as it would to get Botox on, say, your face or your armpits. In fact, it doesn't even require numbing the area first, although Dr. Rowe adds that he sometimes numbs the hairlines since that area tends to cause the most pain.

As for what to expect afterward, Dr. Sarkar says it's pretty anticlimactic. "It just looks a little bit wet but otherwise no change. That night or the day after it may hurt a little, but most people take a Tylenol if they need it and don't report any pain afterward." It usually takes five to seven days to see results, but it can take up to two weeks to have the full effect.

And unlike Botox used for wrinkles, which typically wears off more quickly, when applied to the scalp it can "deactivate" the sweat glands for anywhere from six to 12 months. So you don't have to go up for touch-ups frequently, Dr. Engelman says. (And also unlike Botox for your face, it's unlikely you won't be happy with the outcome of simply sweating less from your scalp.)

Who is scalp Botox right for?

Botox can't be used on women who are pregnant or breastfeeding, Dr. Sarkar says, but other than that it can be useful for anyone.

"It's great for people who work out a lot, and especially in the summer. It really makes a difference for someone who produces so much sweat that it's affecting her life," says Dr. Russak. "I mostly do it for women who take SoulCycle and hot yoga."

People with curly hair who straighten it, or those with very fine hair, might also find it especially beneficial. "Thin or fine hair tends to lose body and get oily quicker than coarser hair after sweating," Dr. Sarkar explains. "Similarly, after sweating, someone who straightens their hair has to often blow-dry it again if it's naturally curly. So if having a coiffed look is important to you, or you always blow-dry in the morning and want to cut down get-ready time, it can make sense to try it. (Plus, there's even some evidence that it may help with hair growth.)

On the other hand, if you tend to wash and go after your workouts (and don't mind it), Blotox probably isn't a worthwhile investment for you. As you can probably guess, insurance does not cover the procedure, which is probably the biggest downside, according to Dr. Sarkar. While the cost will vary depending on how many units you need, 100 units of Botox (the low end needed for this treatment) costs somewhere around $525, in addition to added costs for things like the physician's time and materials, she explains.

"It's an indulgent procedure. It's certainly a niche," adds Dr. Engelman. "I have hair that behaves. I would not do this."

Bottom line: If your hair isn't super unruly or sweating isn't a major issue for you, there are much less extreme options available (like these seven ways to extend a blow-out). But if you're not working out because you don't want to mess up your hair and you've got the cash to spare…have at it.