Theraworx - Ultimate Cramp Killer?

With summer heat kicking in, so has cramping after long rides/races. After dealing with more hamstring cramps then I can count, a friend recommended Theraworx foam cream (topical magnesium sulfate). Supposedly after their last hard race, a few hours later they could barely bend their legs. They applied the foam, 2 minutes later they could bend 25 degrees cramp free, applied again and it was quickly “safe” to sit down with bent legs. Good to go the rest of the night.

Anyone else have experience with this product? Seems designed for elderly people, but any harm or negative impacts using for cyclists? Any blunted adaptations? I know I certainly wouldn’t miss cramps.

Side note: Quick science search shows limited benefit from magnesium sulfate, but 4.5/5.0 star review on Amazon with 11.2K reviews would state it’s either highly effective or an amazing placebo…