@leahramsay When searching for a red light therapy device, consider using the list of FDA approved devices. That way, you can be sure that the output has been verified.
Here is an article to read:
https://nicebeam.com/blogs/blogs/6-complete-list-of-fda-approved-red-light-therapy-devices
(I am NOT promoting this company - just saying the text provides some helpful info)

Here is the site for searching to see if a device has FDA approval:
https://www.accessdata.fda.gov/scripts/cdrh/devicesatfda/index.cfm