New regulations have kicked in Monday for electronic cigarettes and some tobacco-related products, giving the U.S. Food and Drug Administration greater control over what can be sold and limiting the way retailers interact with customers.

Such restrictions, however, are nothing new to California's owners and operators of "vape bars," where customers gather to smoke e-cigarettes. Two months ago the state launched its own restrictions, including raising the legal age from 18 to 22.

All products that use a device in which a flavored liquid is heated into vaporized so it can be inhaled must now earn government approval. Also, merchants can no longer give free samples to customers, must ask customers for age-verifying identification and cannot claim that their products help smokers quit tobacco, store owners say.