I started green coffee bean extract a week ago because I'm trying to lose my last 15 pounds. I'm experiencing no side effects. If you buy the pure kind, it has no ingredient other than the green coffee bean extract which contains chlorogenic acid. There's very little caffeine, unlike diet pills - it's way less caffeine than a cup of coffee. It claims to reduce blood sugar and helps the liver to break down fat. But there are incredibly limited studies on this and could well be just the latest "gimmick". I'll check in after a month or two to let you know whether it's helping. Ultimately, I intend to keep eating healthy and walking. Or as I like to say to myself "stop stuffing my pie hole".
I also love the Fitday goal weight tracker and food log. I've been using it for years and it's fantastic