There's a photobiomodulation trial in the US someone posted on a few weeks ago; it is not the type of photobiomodulation that I was referring to in my post, however -
I was wondering about the mechanism of devices applied on the head, like the 'bucket hat' / coronet with red or near infrared lights - there are trials on in Australia and I have seen posts where people have written about mail ordering these devices.
You can get all kinds of LED devices in the US, but not approved or marketed for PD. You can get, for example, devices designed & approved for hair growth - what they will do for other things, who knows. They might affect the skull bone marrow since it seems like the light could penetrate that far.
Sauna bathing could possibly be beneficial - but I'm not aware of any trials for PD, unfortunately. It might not be safe for people with autonomic dysfunction (could overheat).
Here's Rhonda Patrick's article on health effects of sauna:
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