BEIJING - China's State Food and Drug Administration (SFDA) required manufacturers of dietary supplements to tighten the control of raw materials in a circular issued on Friday.

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Manufacturers are now required to review the qualifications of raw material suppliers and inspect the production of suppliers regularly, the SFDA said in the circular.

The suppliers must improve the quality control of raw materials and manufacturers should develop a detailed record of raw material purchases so that the sources of raw materials can be easily tracked, the document said.

The SFDA also asked its local branches to tighten the supervision of manufacturers who use expensive and rare extractions from animal and plants and imported raw materials.

Manufacturers that use substandard raw materials to produce dietary supplements will be seriously punished, the document said.

The SFDA pledged to publicize information on dietary supplements with health risks and stop its distribution.

The circular is part of the SFDA's efforts to regulate the industry of dietary supplements, which will last throughout the year.

Dietary supplements have become increasingly popular among Chinese consumers due to their awareness of health issues. But the quality of dietary supplements and the number of advertisements that exaggerate effects to mislead consumers has long troubled the industry.