by Fabiana Buontempo, BuzzFeed Staff

Fuller, thicker eyebrows seem to be everywhere — with treatments like microblading and eyebrow lamination becoming increasingly popular. But lately, there's been another eyebrow beauty hack quickly making the rounds on TikTok and Reddit.

The hack is people applying Rogaine — yes, the old school hair regrowth treatment for thinning hair — directly to their eyebrows in an effort to grow them fuller.

As someone who has personally tried various hacks to grow fuller eyebrows — such as brushing castor and coconut oil onto my brows with a spoolie — I was eager to get to the bottom of this hack.

So I enlisted the help of several experts to explain the ins and outs of using Rogaine on eyebrows. I wanted to find out if it's a method they think is worthwhile, what the effects are of using Rogaine on your face, and what other hair regrowth practices they recommend.

The experts are:

• Enrizza P. Factor, MD., board-certified dermatologist and researcher
• Michele Green, MD., cosmetic dermatologist
• Elizabeth Mullans, MD., board-certified dermatologist and founder of Uptown Dermatology
• Carla Gray, eyebrow specialist and owner of Carla Gray Brow Studio in Sola Salons

For starters, it's important to discuss how exactly Rogaine works. The popular FDA-approved hair treatment is an over-the-counter product that is primarily used on men or women's scalp where they are experiencing baldness.

Michele Green explained how Rogaine's active ingredient, minoxidil, works by prolonging the growth (anagen) phase of the hair follicles, which slows down or stops hair loss. "The solution works by relaxing the blood vessels, thus increasing blood circulation to the scalp," she told BuzzFeed.

However, Green advises against using it on eyebrows. "I do not recommend Rogaine for use on other parts of the body aside from the scalp," she told BuzzFeed. "It should definitely not be used on eyebrows since brows have a different cycle of growth compared to the hair on the scalp."

Enrizza P. Factor agreed and added that if someone was to put Rogaine on their eyebrows, they might experience itching and irritation on the surrounding skin since — it's technically not meant to be applied to your face.

"Rogaine also contains alcohol, which means that you should only treat the affected area [your scalp] with it — and take special care to avoid getting it in your eyes or other sensitive skin areas," Factor said.

Green explained that if you were to put Rogaine on your brows and get any minoxidil in your eyes, you may experience irritation, burning, and a potential decrease in visual acuity, which is "the eye's ability to distinguish shapes and the details of objects at a given distance."

A few of the experts provided suggestions on alternative methods for regrowth.

"I suggest a product such as Latisse which is specifically formulated for hair regrowth on the face," Green told BuzzFeed.

"Latisse can be obtained by a prescription from your doctor and should be applied once a day for 16 weeks for the best results," she said. "Although it's technically meant for lashes, it can also be applied to your eyebrows using a combing and sweeping motion."

Dr. Green also mentioned GrandeBROW Brow Enhancing Serum ($38) and RevitaBrow Advanced Eyebrow Conditioner Serum ($110).

"These eyebrow serums typically contain peptides, lipids, conditioners, and antioxidants that will help to nourish the hair follicle and strength the hair strand, promoting eyebrow growth with minimal side effects," she said. 

If you are planning on using any sort of hair regrowth product on your brows, make sure to read the ingredients and know your skin type first, because some – including Latisse — can cause a reaction.

"Latisse does have ingredients that can cause hyperpigmentation of the skin, so just be mindful of ingredients and your skin type [when using these products]," Carla Gray told BuzzFeed. 

Carla said to always discuss with a doctor, if you can, before using any hair regrowth product on your face. 

If you want to go the supplement route, Dr. Elizabeth Mullans recommended biotin. "Biotin can help curb hair fall, stimulate keratin production, and can speed up the rate of follicle growth," she said.

"Another step you can take is to avoid plucking, waxing, or threading your eyebrows," explained Dr. Green. "These hair removal methods can damage the hair follicles, causing your eyebrows to grow back finer and sparser over time."

And, of course, Green added that "eating a balanced diet and making sure you are getting adequate nutrients can help promote hair growth and slow down hair loss."

If you're concerned about thinning brows and the cause behind it, Green said it could be due to several different factors.

"Hair loss and any eyebrow hair loss can be potentially associated with underlying medical conditions or hormonal imbalances," she said. 

Ultimately, when it comes to trying any hack or trend seen on TikTok or Reddit, always speak to a doctor first.

"Not every beauty tip on [the internet] is worth following, and generally it’s better to check with a professional first," Mullans told BuzzFeed.

"Some of these skincare trends can do more harm than good, with many people following and not really understanding the risks around each trend."