Do you take melatonin? Months ago, I was getting a lot of hypnic jerks. I stopped taking melatonin and started taking a magnesium supplement. Since then, I get fewer jerks. They still happen but sometimes I can sense them coming and can stop it by taking a deep calming breath. To be honest, I can't be sure if it was removing melatonin or adding magnesium or both that caused the improvement, but I feel comfortable now with my supplements. If you try magnesium, start with a low dose because it has a laxative effect that can send you to the bathroom. I was taking 3mg melatonin at bedtime. Now I'm taking 250mg magnesium in the morning with breakfast.