Could Wearing A Simple Cap Be The Solution To Thinning Hair? Experts Have Thoughts. (2025)

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Red light devices are quickly gaining attention not only as a way to erase our fine lines and wrinkles but also as a potential solution for thinning hair, according to buzz from /r/Tressless Redditors looking to save their receding hairline and TikTokers who just want a little extra hair length.

Treatments are noninvasive and as simple as wearing a cap, but what do dermatologists and other hair restoration experts think about this red light trend?

Costing upward of $500, are these devices worth the hefty price tag? Or is this yet another social media fad that is more hype than substance?

How Does Red Light Therapy Help Grow Hair?

In theory, red light therapy or low-level light therapy (LLLT) works by using specific wavelengths absorbed by mitochondria to increase cellular energy, enhancing healing, blood flow and stem cell activation. In addition to building collagen and repairing damaged skin cells, this energy boost could also promote hair growth.

Dr. Kimberly S. Salkey, a board-certified dermatologist and the residency program director for the VCU School of Medicine’s Department of Dermatology, said: “One theory suggests [red light therapy] impacts mitochondria inside hair follicles, ultimately leading to increased cellular energy and protein production. Another theory proposes that it triggers dilation of blood vessels leading to improved blood flow and decreased inflammation.”

Keyword: “theory.”

As HuffPost recently reported about red light therapy devices, while studies show promise, they are currently too limited to prove the claimed benefits of LLLT.

“There are also some studies that show that red light may help to restore hair for those with male or female patterned hair loss, but larger studies are needed,” said Dr. Hadley King, a New York-based board-certified dermatologist and clinical instructor of dermatology at the Weill Medical College of Cornell University.

King also notes that while red light therapy with LED lights appears to be safe in the short term, there is a lack of research looking at the long-term effects.

That said, experts acknowledge that at-home red light therapy may offer some benefits — if you’re willing to pay a pretty penny for a treatment that might work.

“While it’s not a cure-all, I do see [red light therapy] as a useful tool, particularly for early to moderate hair thinning,” said Dr. Ross Kopelman, a New York-based hair restoration surgeon. “I see red light therapy as a way to energize weakened hair follicles and keep them in the growth phase longer.”

Dr. Kseniya Kobets, a New York-based board-certified dermatologist and director of cosmetic dermatology at Montefiore Einstein Advanced Care, notes that while at-home devices are less potent than those found in medical offices, they do offer the advantage of being able to be used more frequently.

If you do decide to try a red light device for hair growth, King says patience is key.

“Because of the hair growth cycle, it’s generally recommended to wait six months before assessing the results of any kind of treatment for hair growth,” King advised.

What You Should Know Before Using Red Light Therapy For Hair Growth

First, you should understand that red light therapy alone won’t fix your hair loss.

Ultimately, the best thing you can do to prevent or reverse hair loss is see a medical professional.

“Hair loss is often multifactorial and it’s important to get a diagnosis at a board-certified dermatologist’s office to make sure you’re not missing medical reasons for why hair loss is happening,” Kobets said.

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For some people, red light therapy may enhance other treatments, such as minoxidil, finasteride and platelet-rich plasma.

“I often recommend [LLLT] as part of a multi-modal approach, where patients use it alongside other treatments to optimize hair growth,” Kopelman said.

As always, it’s best to consult your medical provider first to check for potential interactions before beginning red light therapy.

“I usually tell patients to space [LLLT] out from microneedling to avoid excessive inflammation,” Kopelman said. He warns against applying topicals like minoxidil right before red light therapy, as it may increase scalp irritation.

Who Shouldn’t Use Red Light Therapy

1. Those with photosensitive and heat-sensitive skin conditions

While the experts we spoke to say red light therapy has few side effects for most, some readers should think twice before trying this treatment.

“Caution should be used in patients with photosensitive conditions like lupus and those on medications that cause photosensitivity like tretinoin cream or gel,” Salkey said.

Research indicates that visible light can worsen the symptoms of certain pigmentation disorders, such as melasma, Kobets explained.

Kobets also warned that red light devices that generate heat, like those using infrared waves, may worsen inflammation and cause hyperpigmentation.

2. Those with advanced balding or scarring

“If the hair follicles are completely gone … red light therapy isn’t going to bring the hair back,” Kopelman said.

Our experts explain that while those in the early stages of hair thinning may benefit from LLLT, those in the advanced stages of hair loss will see little (if any) improvement. This can include advanced pattern baldness where the scalp is smooth and shiny, severe traction alopecia with permanent follicle damage, or hair loss from scarring due to surgery or inflammatory conditions.

What To Look For If You’re Buying A Red Light Therapy Device

“The biggest downside [to red light therapy] is the cost,” Salkey said. “I generally advise my patients that if you have the money to spend on it, it’s worth a try. If it will be a significant financial burden to purchase one of these devices, the potential benefit may not be worth it.”

To get the bang for your buck, experts recommend looking for the following key factors to ensure your red light device is safe and effective for hair growth.

LEDs vs. Lasers

While most red light therapy devices intended for skin care use LED lights, some devices designed specifically for hair growth, such as the Hairmax PowerFlex Laser Cap, highlight their use of lasers — often at a very steep price.

The Hairmax cap with 272 laser diodes will run you about $1,499. Meanwhile, the similarly designed iRestore Professional, which uses a combination of laser and LED diodes, will cost $899.

Is this just marketing hype, or do lasers actually boost hair growth?

“Energy [from lasers] are directed deeper to the base of the hair follicle making it more effective because it’s not reflected off of the skin and scalp,” Kobets said. “This theoretically makes laser diodes more effective when used alone or in combination with the red light therapy.”

However, depending on your hair goals, you could still benefit from using a red light device you already have, such as an LED panel (or, if you’re particularly creative, an LED mask placed on your head).

“Some LED-based devices still have benefits,” Kopelman said. “But if a patient is serious about getting results, I usually recommend a laser-based device over an LED one.”

Number Of Diodes

Generally, the more diodes (i.e., light bulbs) a device has, the more expensive it becomes. For example, the iRestore Elite helmet with 500 diodes costs $1,899, whereas the Essential model, with 120 diodes, costs only $499.

But is it worth shelling out more cash for a model with more bulbs?

If your goal is to buy the most powerful device possible, our experts recommend looking for a device with more diodes (if your budget allows for it).

“[A greater] density of lasers improves efficacy — the more diodes that emit the energy, the more energy gets delivered to the scalp and more energy output,” Kobets said.

If you still want to try red light therapy for hair growth but don’t have nearly $2,000 lying around, a device with fewer diodes could still potentially be useful (keeping in mind more studies need to be conducted on red light therapy) — you just might have to dedicate more time toward your treatments.

For example, the LaserBand 82 from Hairmax, which has 82 diodes and runs about $800, suggests treatment sessions as short as 90 seconds, whereas the Ultima Classic Comb, containing only nine laser diodes but costing only about $200, suggests an 11-minute treatment time.

Wavelengths Used

Since red light therapy relies on specific wavelengths, experts recommend checking the manufacturer’s website to ensure the device falls within that optimal range.

“Some studies have shown that the 600-700 nanometer wavelength range has an effect on hair growth, while another study showed that 830 nm had greater effectiveness than other wavelengths,” said King, referring to an article published in the Indian Journal of Dermatology.

Kopelman recommends looking for devices that use wavelengths between 630 nm and 680 nm.

Device Shape

There’s no shortage of red light device shapes — from LED panels to combs to helmets. But what do the experts recommend if you want to grow your hair?

Well, that depends.

“I find hair devices that are combs and bands that comb through the scalp, moving the hair around, may be more efficient since the hair is not in the way of the energy being delivered,” Kobets said.

That said, the most effective treatment is one that you can stick with. If you don’t see yourself spending over 10 minutes combing through your hair multiple times a week, a helmet or a cap design may be more your speed.

“I would recommend a helmet or cap design because these [devices] place the lights close to the scalp and less motivation is required for regular use compared to a brush design,” King said.

FDA Clearance And Clinical Studies

As there’s no shortage of cheap knockoffs from dubious origins available online, the experts advise choosing a device cleared by the Food and Drug Administration to ensure your safety.

“Consumers should stick to FDA-cleared devices when making a purchase. They should be aware that this is not an attestation of efficacy, but it does ensure a degree of safety,” Salkey said.

As Salkey noted, FDA clearance only ensures the device’s safety, not necessarily its effectiveness. Thus, our experts also recommend checking whether the company has conducted any clinical studies.

“I encourage patients to check whether the company has actual studies to back up their claims rather than just marketing hype,” Kopelman said.