get a broad spectrum red light bulb, that is most well understood and is least risky. Cons is the targetted spectrum would be only a small portion of it but good thing is it is a 4$ cheap test. It worked for me for smaller issues, like minor burns, cuts etc.

Build your own. But direct from Alibaba or mouser or digikey.

The main science behind it is to hit the absorption peaks of a mitochondrial enzyme. You can make em bright, but be limited on how long you can use it, or dim and be forced to use it constantly for the same effect.

Pulse width modulation is very important in this for penetration. High intensity allows for deeper penetration, but heats up cells causing stress. The ideal scenario is a really strong light, run at a really low duty cycle, allowing for both intensity AND low average wattage, this lessening thermal issues

There might be other mechanisms of actions, as there are so many papers that say "light good", but until they can give a mechanism of action, I'm sticking with what I know

Light is light.