Hair loss isn’t always dramatic. It can be incremental. You start noticing a bit more scalp in harsh bathroom lighting; a tiny bald spot when you tie your hair up in a ponytail. The shower drain is more clogged than usual. Not long ago, hair loss treatments meant topical remedies, supplements, or a flight to Turkey. Luckily, red light therapy brings the potential for hair regrowth into your home—no clinical appointment required.

Beyond skin rejuvenation, research suggests red light therapy can help energize hair follicles, increase blood circulation in the scalp, reduce inflammation, and lower dihydrotestosterone levels—a hormone that causes hair loss and thinning. Red light therapy also supports adenosine triphosphate (ATP) production, which helps provide oxygen and blood flow to the scalp and triggers follicles to remain in the hair growth phase.

To determine the best red light therapy for hair growth, I tapped three WIRED tech reviewers who’ve dealt with hair loss themselves. We assessed red light therapy caps, hands-free helmets with full scalp coverage, and low-level laser therapy or photobiomodulation devices for 16 weeks. Along the way, we reviewed the research, spoke with dermatologists, and tracked ease of use. These are the favorites that produced meaningful results and earned our trust.

Be sure to check out our other hair care guides, including Best Dry Shampoos, Best Heat Protectant Sprays, and Best Hair Dryers.

Best Red Light Helmet

CurrentBody’s LED Hair Growth Helmet is a wearable, cord-free, Bluetooth-enabled device aimed at improving hair’s density, thickness, and overall condition. Each panel on the helmet has 12 red lights (120 total), which are on a spectrum of 620 to 660 nanometers (nm). The 620-nm red light helps improve scalp health by promoting circulation, and the 660-nm red light penetrates deeper, reaching through the epidermis and dermis to the hypodermis, where it stimulates growth and repair at the follicle root. According to CurrentBody, you only need to use the device for 10 minutes a day, and you’ll see results within 12 weeks.

My hair grows famously slow. I got a pixie cut in the spring of 2011, and my hair did not touch my shoulders until the end of 2013. My hair is also super fine. It tangles easily and often breaks off (my ends are chronically dry and split). After 12 weeks, I didn’t notice a huge difference in length (and I got a haircut halfway through testing), but I did notice that my hair seemed to be sprouting new follicles along my scalp and sideburn area in particular. I started to see small baby hairs along my hairline that I had never seen before. My stylist commented that my hair felt thicker, and I noticed less breakage and hair caught in bristles when brushing. My balding roommate also tested it (although not daily like me) and said that his hair felt thicker and that there was new growth around the scalp.

The helmet comes in two sizes: medium for a skull circumference of 21.3 to 23.2 inches, or large, for 23.3 to 25 inches. (I opted for medium, and it was too large for my head size.) The device sits on a base and is charged via a USB-C cord. It takes about three hours to fully charge, and it stays on a single charge for about a week. The device is powered on by the press of the single button located under the charging port. The circular earmuffs protect sensitive ears with a cushy, removable faux leather cloth, and they can be adjusted several inches up or down to ensure a comfortable fit. The screen on the right earmuff indicates the time left in the treatment session, and the helmet automatically turns off when the 10 minutes are up. You can also connect the device to Bluetooth and play any type of music or video while wearing it, because God forbid I be left alone with my thoughts for 10 minutes a day. Just make sure your hair is clean and dry before use.

My only complaints are that the ear covers aren’t the easiest to adjust while wearing and would oftentimes pull out my hair while I removed or adjusted the helmet. Nevertheless, this is the best red light therapy for hair growth. Just you wait, I’ll look like Fabio on the cover of a romance novel by next year. See full review here. —Molly Higgins

Best Red Light Cap

At first glance, the HigherDose Red Light Hat looks like your everyday black baseball cap, with a brand logo embroidered across the top. Nothing to see here—until you notice the little battery cap and controller on the back, or see the inside to find 120 LED bulbs lining the inside to turn it into a red light therapy device made for your scalp and hair. It uses a single wavelength at 650-nm red light and you wear it for 10 minutes a day. The starting program is to wear it every single day for 16 weeks, and then five days a week from then on out.

While I have shoulder-length hair and don’t suffer from natural hair loss, I’ve struggled with trichotillomania since my teens. It’s like nail biting, but instead you rip out your hair. I’ve had to get an embarrassing number of haircuts designed to hide a bald patch or blend a weird short regrowth section in with the rest of my hair, and my hair isn’t nearly as thick as it used to be after years of this terrible habit.

Part of what initiated the habit is that any time my sensitive scalp gets irritated or has any kind of bump, the itchiness from it drives me to pull at the hair around the spot. But in the months I’ve been using the HigherDose hat, I have felt like my scalp has been happier, with fewer irritated spots and overall itchiness, leaving me less likely to reach for my scalp. In October, after my first month or so of using this device, my hair stylist noted that she saw healthier regrowth instead of the breakage-style she usually sees. In January, she took another look and noted that my usual problem spot on the back of my head had grown in better than ever. She didn’t find any reaction on my scalp either from four months of using the device, and my roots look thicker all around my head.

Similar to my infrared brushes, I do find my hair is a touch oilier after I use it, since both use infrared light that can help lock in moisture. It’s not a problem on days when my hair is clean, but if my hair is already dirty, using this hat only reminds me further that I need to wash it. Overall, though, using this device has had a serious payoff for me, my scalp, and my hair. See full review here. —Nena Farrell

Best Low-Level Light Therapy

Where many turn to red light masks to unlock glowy skin, I was curious to know if it could help me with my long-standing scalp issues. I seem to rival a golden retriever in terms of shedding, and my sensitive skin makes things itchy and flaky. To nip it in the bud, I tested the iRestore Elite device, along with the Max Growth kit. It sits right on the crown of your head, and it does heat up quite a bit as the red light puts focused emphasis on your scalp. The red light exposure has helped prevent flare-ups, as I have none to note from my time testing it. That’s a feat in itself.

However, I’m not the success story here. I recruited a balding tester (my husband, who also gets to give products a spin) who wanted to give it a go to see if it would help with his receding hairline. After three months of consistent use, his hair density has bounced back significantly. It’s a regular sight to see him drink his morning coffee while waiting for the Elite’s 12-minute run time to wrap up. The Max Growth kit smells wonderful but also played a contributing role in his follicular blossoming. Now, if only he would stop taking it out of my shower. See full review here. —Julia Forbes

Compare Top 3 Red Light Therapy Devices

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