There's lots of research to indicate that Red Light will improve the mitochondria and energy levels in humans and animal studies.
I was watching a youtube video by Prof Glen Jeffery, who runs the Ophthalmology lab and UCL. He mentions the success of Red Light to improve vision in aging population and makes the point that this is due to the eye having more mitochondria then any other part of the model. In passing he also mentions that Near infra-red light improved Parkinson symptoms in Monkeys. So I looked it up and this is the case.
pubmed.ncbi.nlm.nih.gov/264...
Jeffery's talk is here.