I have asked several times for some help with sleep. My doctor suggested Benedryl, which did me no good. Prior to chemo, 1 Benedryl would knock me out for a good 10 hours. One of the nurse practitioners offered yet another prescription med, which I declined. I'm on more prescription meds than I can shake a stick at! I finally pressed her on how much melatonin and magnesium I could take for sleep. She said there is no upper limit on magnesium, but to be careful, and that I could take up to 10 mg of melatonin per night. I am now sleeping well on 9 mg of melatonin. I add 200mg or so of magnesium and some ashwagandha if I feel particularly restless at bedtime. It's worked great!