Red Light Dosing Cheat Sheet

Red Light Guide · Last checked 2026-10-26

1 · The formula

Dose (J/cm²) = Power density (mW/cm²) × Time (s) ÷ 1000
Time (s) = Target dose × 1000 ÷ Power density

20 mW/cm² mask × 6 min = 7.2 J/cm² (skin) · 50 mW/cm² panel × 10 min = 30 J/cm² (deep). Use power density at your distance.

2 · Dose bands (at the skin)

Goal	Dose	nm
Skin	2–10 J/cm² stay <~20; masks 5–9	630–660
Deep (muscle, joint)	10–70 J/cm² many studies 20–40	810–850
Upper limit	<~80–90 then diminishing/reversed	any

Sources disagree at the edges — start low, adjust.

3 · The Goldilocks rule

Too little → nothing. Just right → response. Too much → benefit fades or reverses. More minutes ≠ better. Hit your dose, then stop.

4 · Distance rule of thumb

Distance	Power	30 J/cm² @ rated 100
1× (≈15 cm)	100%	5 min
2× (≈30 cm)	~25%	~20 min
3× (≈45 cm)	~11%	~45 min

Inverse-square estimate; big panels fall off more gently up close. Prefer a measured chart. Mark your spot.

5 · Too-much warning signs

Early benefit that fades
Feeling worse / “crummy” after sessions
No change after weeks of consistent use
Skin redness, dryness, irritation

Fix: cut time or intensity ~50%, rebuild slowly. Persisting? Stop; ask a clinician.

6 · Habits

Consistency beats intensity · Protect your eyes (NIR is invisible) · Ask a clinician first if pregnant, have/had cancer, or take light-sensitising medication.

Educational only. Not medical advice, diagnosis, or a device prescription. Red Light Guide does not claim red light treats or cures any disease. Ranges summarise published research (Huang, Hamblin et al., Dose-Response 2009) and third-party reviewer notes (Light Therapy Insiders, via our research notes through Jan 2026). We have not lab-tested devices.