The article is also about trans-cranial stimulation with near infra red. Sunlight is rich in near infra red so it sounds quite plausible that it might have som

The article is also about trans-cranial stimulation with near infra red. Sunlight is rich in near infra red so it sounds quite plausible that it might have some effect if the article is correct about the LED helmet being effective. People interested in red light therapy have already discussed this, see https://redlightman.com/blog/red-light-therapy-vs-sunlight/ https://redlightman.com/blog/red-light-therapy-vs-sunlight/ for instance.