The devices are appearing in clinics, luxury hotels and home bathrooms at roughly the same rate that the clinical evidence is accumulating. The timing is not coincidental.

Red light therapy, also called photobiomodulation, uses wavelengths between 630 and 850 nanometres to penetrate skin tissue. The proposed mechanism is straightforward: light at these wavelengths stimulates mitochondria, the energy-producing units of cells, improving their function and reducing oxidative stress.

The research is genuinely promising in specific areas. Wound healing, reduction of inflammation and improvement in skin texture have the most consistent support in peer-reviewed literature. Studies on muscle recovery and joint pain show encouraging results, though sample sizes remain small.

Where the evidence becomes thinner is in the broader longevity claims. The idea that regular red light exposure meaningfully extends cellular lifespan is not yet supported by robust human data. Most studies have been conducted on cells in a laboratory or on animal models.

The practical question is this: at what point does a therapy with genuine but limited evidence justify a significant investment of money and time?

The answer depends on what you are treating. For skin health and muscle recovery, the evidence is sufficient for a considered decision. For broader anti-ageing purposes, patience is the more informed position.

The devices themselves range from a few hundred to several thousand pounds. The difference in quality is real. Output power, wavelength accuracy and device surface area matter considerably. A cheaper device is not necessarily a waste of money, but the specifications should be verified before purchase.

Red light therapy is not something to dismiss. It is also not the longevity protocol it is sometimes marketed as. The distinction matters.