If you normally don’t fast well- don’t take these! I know somoeone who took them and got so dehydrated and couldn’t get back to their normal self the next day that they ended up in the ER.
I know many people who use the tzom kal tablets and they say it helps them greatly in fasting better and easier. It makes no difference to me whether this is physical or psychological, if they feel better for taking them then it’s worthwhile and they work.
I’ve used kali tzom with success. They are not caffeine or asprin – they contain herbs (I think they you not lose water as quickly so you don’t dehydrate). Maybe it’s psychological – I don’t care! It worked!
Taking a 24 hr. drug before the fast helps. People in their homes sell 24hr Tylenol or 24 hr aspirin to help support a Kollel in Toronto. I personally take a 24 hr NSAID.