L-carnitine is a natural supplement and is already found in the body. It's value in burning fat in overweight people is of great dispute, but this would not apply to someone who didn't have excess fat even if it does aid in dieting. Of course, this claim does help sales to dieters. However, some countries only allow its use by prescription because these diet claims are not proven, so the attitude is they won't allow it to be sold because they see it as taking advantage of people trying to lose weight. Unfortunately, this deprives people who want to use it for reasons that have been proven, such as an ability to promote nitric oxide levels in the blood which helps keep blood vessels functioning properly. I won't say that L-carntine is something everyone should take but people in a chronic low oxygen state (any anemia) can benefit from its use.