Generate text that best answers this question: alternative medicine
The marketing of dietary supplements in North America: the emperor is (almost) naked.
BACKGROUND: Many different dietary supplements are being sold in North America. The quality of the evidence supporting their efficacy covers a wide spectrum: Some are based on solid science (such as vitamin D and fish oil), whereas with most supplements there is little or no supporting evidence. Types of supplements commonly sold include exotic fruit juices (such as goji juice) and single herbs or mixture of herbs. Common claims made in support of particular supplements are that they are rich in antioxidants, induce detoxification, stimulate the immune system, and cause weight loss. Supplements are commonly sold through health food stores and by multilevel marketing. Sales may be promoted using bulk mail ("junk mail"), spam e-mails, and Web sites. A large part of marketing is based on claims that are blatantly dishonest. CONCLUSIONS: Whereas supplements for which good supporting evidence exists generally cost around $3-$4 per month, those that are heavily promoted for which there is little supporting evidence cost about $20-$60 per month. The major cause of this problem in the United States is weakness of the law. There is an urgent need for stricter regulation and for giving better advice to the general public.