Madeleine Finlay

But the principle behind all this is that these masks are supposed to stimulate our cells to make more collagen.

Does it work?

Well, Jonathan told me they had done tests in the lab.

Ian, I'm going to get us T-shirts printed with the phrase promising but needs more evidence because I'm about to say it again.

There have been studies looking at the impact on acne and uneven skin tones or even skin conditions like psoriasis.

And red light therapy does seem to help for acne.

For example, one study found that it reduced spots more than a topical retinoid and an oral antibiotic.

But I think more studies are needed, more trials are needed.

I do think it's a mainstay experience of science journalists that we get really excited when we see a headline and then we read on and get that disappointed feeling when we see that it's actually just research in mice.

Because humans are, of course, very different from mice.

But saying that, actually, a review from last year from multiple specialists concluded that red light therapy was safe and effective for androgenic alopecia, which is pattern hair loss in men.

That's the classic kind of hair loss on the crown or at the front.

And for women, it's the sort of general thinning that you might experience.

And another small trial using red light therapy did appear to have some benefits in terms of reducing hair loss and improving hair thickness.

Well, I hesitate to tell people how to spend their money.

If it was me, no.

Because in my opinion, having looked at the evidence...

There is a little bit, but there's so few good trials with lots of participants and it's really not clear what the right dose is or if that's what you're going to get from a commercial product.

There's no standard.

There's no kind of set thing.