Anywhere from 50 to 100mg's but keep in mind I've been taking it since 03 so my tolerance is pretty built up to diphenhydramine(aka benadryl) As for Phenibut, it's not something you wanna take long term, or even everyday on a consistent basis b/c your tolerance builds up quickly and it CAN become addictive according to certain studies, but I've found it's more habit forming than actually being physically or psychologically addictive and I've taken phenibut everyday to every other day in the past up to a full month with no problems. It's def a safer alternative to benzo's to take the edge off for 3-4 weeks while going through WD's. I would only recommend it no more than 3 to 4 days a week to keep it's effectiveness though. You can dose it strictly for sleep or you can take it during the day to take the edge off from the WD's and to get a little relief from feeling like shit. Personally I like phenibut in the day time for anxiety(1000mg-1500mg) and for sleep I take my benadryl, 3-5mg of melatonin, 200mg's of L-Theanine, and a gram of valerian root. You can get all those at any health food store and at most places like wal-greens, super-d, wal-mart, etc. I've never seen Phenibut at a place like wal-mart but any health food store should have it.