Not sure what the problem here is.
It's exactly the same standards applied to herbal medicines and vitamins. They're limited on what claims they can make. They can say it MAY aid in weight loss, but if they say it WILL make you lose weight then they have to have the laboratory studies to prove it.
It's just a standard to prevent companies from making false claims. While most people may believe that ecigs help people stop smoking there is no definitive medical study that says so, so it's illegal to advertise ecigs as a proven stop-smoking method. Likewise you have to be able to show the medical and scientific proof that it's safer before you can make such claims in advertising. And that means long term studies on thousands of people using the specific product being sold, not just a few samples taken from random products.
This doesn't limit sales at all, it simply limits how the products are advertised. You can't make advertising claims without being able to prove with proper medical studies that your claims are true. It simply requires that ecigs conform to the FDA Bad Ad and mislabeling/misleading standards.
http://www.fda.gov/Drugs/GuidanceCo...ingAdvertisingandCommunications/ucm209384.htm
http://www.fda.gov/MedicalDevices/D...neralDeviceLabelingRequirements/ucm052190.htm
These same standards are applied to virtually all products being sold as health aids or having medicinal value.