LED face masks - what?

[Brummumm]

Hi,
I keep seeing these. Can someone explain to me what they are, what the science is and how they work?
Are they safe? Are the at home ones far weaker than a salon version?
Thank you! I am just mystified.

They use different colour light as therapy, such as red to boost collagen and/or blue to help with breakouts (it may be the other way round). There is science behind it. I don’t know how they compare to salon therapy but they seem very popular. I know several people who have them

Oh, and a couple of those I know, the mask have some kind of cooling thing for the under eye area

I nearly bought one last week when I felt old!!

I did a lot of research and they aren't as powerful as anything you'd find in a salon.

Still might buy the shark one, but don't have a spare £300.