How old you have to be to buy diet pills?

Is there a certain age you have to be? One of my friends say a lot of places don't check for your ID (she lives in japan). I'm 19 by the way

PLEASE do not use diet pills. They are very dangerous.
Eat well, walk do it the right way the healthy way. Diet pills are a quick fix with very serious possible side effects. It is just not worth it! Be healthy. Just move more, increase your protein fruits and vegetables. You will be fine the natural way.

Indeed, a lot of these pills, teas, etc. are not safe and have resulted in kidney failures and other serious health issues. Just because they contain herbs doesn't mean they are safe, some dangerous toxins are in many.

Anyway, no id check in drug stores to buy otc and supplements.
I had read news articles of fatal accident as the above said.

Japanese government does not authenticate them as legal drugs.
thus, there is no restriction.
whether you take poisonous matters or not is your choice.
I believe the government will not help you, if you become sick after you take them.

My understanding is that you cannot buy diet pills (which are quite different from suppliments) at drug stores in Japan unless you have a doctor's prescription. It has nothing to do with you age moreover your ID. You just need to be sick enough to have the doctor give you a prescription.