I asked this question also, as my 13 year old could benefit from this cleanse. I never did get a good answer. I was advised however to clean up our diet and go "raw" for her instead of the cleanse. My daughter is not overweight, but has terrible acne. I am trying to get healthy and get my family healthy, and she would like to start out healthy too. I'm not sure how much of a strain it might be on someone that age though. Especially if they are in school on the weekdays. It may be hard to do a cleanse like this at school where they are not allowed to eat (drink) anytime they want to - also might be intimidating to them to try to explain to their friends why they are only drinking their meals and not eating the greasy pizza that is served. Please post what you decide to do and how it works if your 13 year old decides to try it. I'm still debating. I think it could be a very positive experience if done in the right way and for the right reasons.