The 1967 Lab "Accident" That Revealed How Red Light Can Wake Up Sleeping Hair Follicles

By the Editorial Science Team  |  Reviewed against published photobiomodulation research  |  7 min read

In 1967, a Hungarian researcher named Endre Mester set out to test whether laser light could destroy cancer cells in mice. The experiment didn't go as planned — but what he noticed instead would quietly launch an entire field of medicine.

Mester had shaved the backs of his lab mice and split them into groups. The low-power red laser he used was far too weak to do what he'd hoped. Yet when he returned days later, he saw something strange: the mice exposed to the red light had grown their fur back noticeably faster than the ones left untreated.

That single observation — fur regrowing under low-level red light — became the founding moment of what scientists now call photobiomodulation, or low-level light therapy (LLLT). More than fifty years later, it's the same principle behind the red light hair devices used in dermatology clinics around the world.

Why would light affect a hair follicle at all?

It comes down to energy. Deep inside each of your cells are mitochondria — tiny "power plants" that produce the fuel (ATP) your cells run on. Specific wavelengths of red and near-infrared light are absorbed by these mitochondria, which can stimulate them to produce more energy.

For a hair follicle, more available energy and better local circulation can mean one thing: a tired, dormant follicle may be nudged out of its resting (telogen) phase and back into its active growth (anagen) phase. In simple terms, the follicle gets a wake-up call.

"The fur on the treated mice grew back faster." — the quiet observation that started photobiomodulation research.

From lab animals to human scalps

What began with rodent fur has since been studied in people. Over the past two decades, low-level laser and LED light therapy for pattern hair loss has been examined in numerous peer-reviewed clinical trials, and several at-home red light devices have gone on to receive regulatory clearance for promoting hair growth.

What the research shows

• Multiple randomized, double-blind, sham-controlled trials have reported measurable increases in hair density versus placebo devices.
• Reviews of the evidence have found LLLT significantly improved hair counts compared with sham across studies in both men and women.
• The wavelengths researchers return to are 660 nm (visible red) and 850 nm (near-infrared).

These studies were conducted on red-light / LLLT devices as a category — not on ReviveCap™ specifically. Individual results vary with age, severity, and consistency of use.

The catch: clinic treatments are expensive and inconvenient

In-office laser therapy can run into hundreds of dollars per session, with repeated visits over months. Premium at-home laser caps often retail for $700 to $3,000. The technology worked — but for most people, the price and the hassle didn't.

That gap is exactly what the Drayvorx ReviveCap™ was built to close.

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Meet Drayvorx ReviveCap™

A wearable red light therapy cap that brings the same 660nm + 850nm wavelengths studied for hair growth into a hands-free device you can wear at home — no pills, no serums, no clinic appointments.

• Dual wavelength: 660nm red + 850nm near-infrared
• Drug-free & non-invasive — nothing to swallow or apply
• Hands-free & lightweight — wear it while you work or relax
• A simple 30-minute session, a few times a week
• Designed for both men & women
• Rated 4.8★ across real customer reviews

$159.99$79.99

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Individual results vary based on age, severity of hair loss, and consistency of use.

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