Weight loss pill for below 15 age

One of my friend asked me yesterday about what weight loss product should be good for her niece. Her niece is below 15 and i don't know if the diet pill that i told her is okay for her. Usually diet pills are only advice to a person who is above 18. But anyways, she said she's going to ask the pharmacist where she is going to get the product. I just hope her niece will learn the alternative and natural way of losing weight and not relying on weight loss pills because at her age i really doubt if there is any weight loss products available for her.