670nm red light exposure improved aged mitochondrial function, colour vision

Evidence and study quality

• Commenters note “thousands” of red/NIR (near‑infrared) photobiomodulation papers showing mitochondrial effects, but many describe the evidence as “large but mostly inconclusive.”
• Complaints: weak or absent control groups, few well‑designed double‑blind human trials, unclear optimal wavelength, intensity, and dosage.
• Some point out UV phototherapy has standardized wavelengths/dosages (e.g., 311 nm), whereas red/NIR work is more heterogeneous and commercially driven.
• Several call for controls with other wavelengths to rule out diurnal or non‑specific effects.

Proposed mechanisms

• Common mechanistic story: red/NIR photons interact with cytochrome c oxidase in mitochondria, displacing nitric oxide, restoring electron transport and ATP, reducing ROS, and releasing NO for vasodilation.
• Others mention links to melatonin production in mitochondria and vision protection from blue/UV oxidative stress.
• Some warn that interfering with oxidative‑stress regulation could have unknown long‑term downsides and that individual factors (genetics, nutrition, magnesium, etc.) may strongly modulate effects.

Anecdotes and perceived benefits

• Users report mixed but often positive experiences: reduced joint pain, faster healing of sprains, better mood, improved sleep, less fatigue, and subjective cognitive benefits.
• Specifics include: red/NIR helmets/panels for brain injury and TBI, red lamps for minor burns and cuts, red glasses for vision, red headlamp reading leading to rapid sleep onset.
• Others say they notice no effect, or can’t distinguish from natural healing or placebo.

Hardware, dosing, and DIY

• Strong interest in building cheap systems from commodity LEDs (Digikey, Mouser, AliExpress) versus expensive branded panels and masks.
• Key parameters discussed: wavelength (around 650–850 nm), irradiance (~mW/cm²), duty cycle/PWM to balance penetration vs heating, beam shaping (lenses), and distance from tissue.
• Several worry that consumer specs (wavelength, power) are often inaccurate or outright fraudulent; spectrometers and datasheets are suggested to verify.
• Debate over how deeply NIR actually penetrates skin and skull; multi‑watt systems can deliver measurable energy several cm deep, but low‑power LEDs may not.

Sunlight, fire, and everyday light

• Many ask whether simple sunlight exposure (especially morning, eyes closed) is “good enough,” given the strong red/NIR component.
• Others note limitations of sun: UV damage, difficulty targeting specific bands, no control over intensity/PWM, latitude/season constraints.
• Fire and IR heaters are proposed analogs; some report pain relief, others say the spectrum/heat makes dosing hard and may mainly just warm tissue.
• Screen red‑shifting (f.lux, SunsetScreen) changes visible balance but does not increase total red/NIR power meaningfully.

Safety, skepticism, and commercialization

• Concerns raised about eye safety (avoid staring into intense IR without protection), localized overheating, and theoretical risk of stimulating existing cancers.
• Several emphasize “more is not better” and that over‑irradiance mainly heats superficial tissue.
• Commenters highlight rampant grift: overpriced panels, $8k “red light guns” with disease dials, and anti‑aging masks sold with dubious claims.
• Overall tone: cautious interest—red/NIR is promising and biologically plausible, but current commercial hype far outpaces rigorous, standardized clinical evidence.