New Clinical Study Adds to the Evidence for Photobiomodulation in Hair Growth
Published: 5 February 2026
Hair thinning affects millions of men and women, yet many available solutions come with trade-offs. These can include side effects, high costs, or difficulty maintaining long-term use. In recent years, photobiomodulation (PBM), also known as low-level light therapy, has gained attention as a non-invasive approach supported by an increasing body of clinical research.
A clinical study published in 2025 adds to this growing evidence base by examining how specific wavelengths of light interact with scalp tissue and hair follicles at a biological level.
The study investigated light in different regions of the spectrum, including visible red light around 650 nm, near-infrared wavelengths around 1550 nm, and far-infrared radiation at approximately 14,000 nm. Each wavelength interacts with tissue differently and penetrates to different depths.
Far-infrared wavelengths primarily interact with tissue through thermal and circulatory pathways and are studied separately from the visible and near-infrared light used in most home-use devices.
Together, these findings help clarify how different wavelengths of light interact with scalp tissue, and why wavelength selection and delivery quality matter.
What the study found, explained simply
The researchers observed that carefully selected wavelengths of red and near-infrared light can trigger measurable biological responses in scalp tissue. These responses include:
- Improved cellular energy production
- Increased signaling molecules involved in circulation and tissue repair
- Reduced biological stress around hair follicles
Together, these mechanisms help explain why photobiomodulation is being studied in hair-related conditions, and why wavelength selection and delivery quality matter.
The study also highlights that different wavelengths act at different depths of the scalp. Red light primarily affects surface-level structures, while near-infrared light penetrates deeper and reaches tissue surrounding the hair follicle.
Why multiple wavelengths matter
Many early home-use devices relied on a single wavelength of light. More recent research, including this study, suggests that combining wavelengths may produce a broader biological response, similar to what has traditionally been achieved with clinical laser systems.
This does not mean that more is always better. Instead, it shows that precision matters. Correct wavelengths, stable output, and even coverage across the scalp are key factors.
What this means for home treatment
For people considering light-based hair therapy at home, the key takeaway is not about waiting for future technology, but about choosing a device designed around today’s best-supported research.
Current evidence consistently shows that specific red and near-infrared wavelengths play a central role in supporting follicle activity and scalp health. When delivered with appropriate intensity, stability, and coverage, these wavelengths can help support a biological environment favorable to hair growth.
As research continues, additional wavelengths and treatment strategies are being explored. These developments help refine understanding over time, but they do not change the fact that well-designed devices based on current evidence are already meaningful and relevant today.
Our approach
At Red Light Labs, we base product decisions on peer-reviewed research and documented biological mechanisms. Our first-generation device focuses on a carefully selected combination of wavelengths that are among the most consistently supported in current hair-related research.
Our product platform is designed with long-term evolution in mind. As new clinical evidence emerges, future generations may integrate additional wavelengths or treatment refinements where science clearly supports it.
We believe progress should be continuous, evidence-driven, and never built on promises that science has not yet made.
View the referenced clinical study on PubMed (PMID: 40398915)
For a broader explanation of how photobiomodulation is used in modern devices and how LED hair growth caps deliver therapeutic light to the scalp, see our complete guide.