There is no reliable evidence, no. However anecdotally I used to put my lower back out about twice a year and was in awful pain until the muscle spasm subsided, usually a week at least. After a particularly bad attack when I had to have Valium and codydramol I got better, but the menopausal constant aches remained in my lower back, hips etc. Fed up, I bought the lady magnet. All I can say is I have had no episodes of flat out back pain since ( we're talking eight years). Not one. I don't wear it all the time, but I do get more achey if I leave it off for long.
It didn't help with any other symptoms of the menopause. And yes, it attaches you to supermarket trolleys and I don't wear it going through security at airports, or getting into gigs....it's not easy explaining it away to sour-faced borderforce officers or burly security persons 🤣🤣