I've only been on it for a few months...started out at 50 mg, but then last visit to my rheumatologist--she upped it to 100mg. I feel much more of a difference on 100 so far. I was very very fatigued when taking it in the morning, so I switched to right before I lay down for bed at night. And that's been good for me. Sorry about the insomnia....what dose are you on? What time of day to do you take it?