A new federal study finds dietary supplements send more than 20,000 Americans to hospitals every year and the riskiest ones are energy-boosting and weight-loss products.

Details of the government research report can be found on the New England Journal of Medicine. It writes unlike the over-the-counter medications the herbal products are not required to identify adverse effects on the packaging.

The study was led by health authorities of the Centers for Disease and Prevention (CDC) and Food and Drug Administration (FDA). They tracked emergency-room visits of more than 3,500 cases for a period of ten years at 63 hospitals.

The researchers said about 43 percent of emergency visits are due to weight loss pills and 46 percent due to energy products compared to prescription stimulants.

The dietary supplement is a rapidly growing $32 billion-a-year industry and over the years has attracted more and more scrutiny. It has also prompted calls for coming up with tougher regulation. In 1994 there were 4,000 types of supplement products and in 2012 it grew to more than 55,000 types.

Several critics say the low level of regulation on herbal products has put many Americans at risk.

Industry expert says the dietary supplements are used by about half of Americans and if believed to the data only small fraction of them had major injuries.