Well, after loads of experimenting with minerals (magnesium, potassium, calcium, etc) there was no effect. Tried hydrating like crazy, again, no help.

I suffer from psoriasis and noticed that in the summer months, when I'm getting tons of sun, it disappears. Gone. Come the first months of colder weather, it slowly comes back and is mostly located on my hips. Nothing too crazy, but it scales and it can't be good. Well, last winter, with 4000 IU daily of vitamin D, my levels were a measly 37. Barely "normal." So with that in mind, I bumped it up to 6000 IU this winter. What do you know? My psoriasis slowly disappeared (it's not totally gone but getting there) and NO cramps. The only thing I changed in my diet was the addition of the vitamin D and this happened almost overnight.

I haven't yet checked my blood levels and will in another month or so, and who knows, I may need to tweak my dosage a bit. It all makes sense though (vitamin D, calcitonin, and calcium metabolism), and I'm frankly embarrassed it took this long to figure this all out. Would make my biochem prof's proud

This is in NO WAY a recommendation to anyone with cramps or psoriasis, just my personal experience. Consult your physician before doing anything like this.