Blood flow sits underneath many of the topics people associate with red light therapy, from warmth and recovery to skin. It is also an area where a real, measurable effect is easy to overstate.
What the research shows
Studies have measured a short-term increase in microcirculation, blood flow in the smallest vessels, in skin exposed to red and near-infrared light. One proposed mechanism is the release of nitric oxide, a molecule that relaxes blood vessel walls. Warmth from the device also widens vessels, as any heat source does.
These effects are local and temporary: they happen in the area exposed and fade after the session.
What it does not show
A short-term increase in skin blood flow is very different from treating or preventing heart or vascular disease. There is no evidence that red light therapy improves cardiovascular health, lowers blood pressure or treats circulation disorders, and our systems are not designed or tested for those purposes.
When to see a doctor
See a doctor for leg pain when walking that eases with rest, cold or discoloured feet, wounds that do not heal, swelling in one leg, chest pain or breathlessness. Physical activity, not smoking and managing blood pressure, cholesterol and blood sugar are what the evidence supports for circulation.
Related reading
See our pages on circulation and vascular health.
