This comes from the seed of the guar plant. Like other dietary fibers, it is said to work by preventing the absorption of fats and helping you feel full.
Guar gum has been studied more extensively than other fibers for weight loss. Most researchers have concluded that it is ineffective.
The Natural Medicines Comprehensive Database says that guar gum is "possibly ineffective."
Side effects may include:
This is a plant that grows in the Kalahari Desert in Africa. According to the National Center for Complementary and Alternative Medicine, the stem of the root was traditionally used by Bushmen to reduce hunger and thirst during long hunts. It's marketed for weight loss as an appetite suppressant.
Hoodia contains P57, an ingredient said to suppress appetite by helping you feel full. But there is no credible evidence that it's safe or effective.
The Natural Medicines Comprehensive Database says it has insufficient evidence to rate the effectiveness of hoodia.
This is found naturally in the body and comes from the metabolism of the hormone DHEA in the body. Unlike DHEA, 7-keto-DHEA does not increase levels of testosterone or estrogen in the body. It may help weight loss by boosting metabolism, so you burn more calories throughout the day.
In a couple of studies, people taking 7-keto-DHEA -- along with moderate exercise and a reduced-calorie diet -- lost significantly more weight than those taking placebo. The Natural Medicines Comprehensive Database says there is still insufficient reliable evidence to rate the effectiveness of 7-keto-DHEA.
It appears to be safe. Researchers have not seen any significant side effects when taken for up to 28 days.
It's also known as ma huang. It is an herb that contains the stimulants:
The FDA banned supplements with ephedra after the herb was linked to serious side effects, including:
The FDA's ban does not apply to traditional Chinese herbal remedies or to products such as herbal teas.
According to the FDA, there is little evidence for the herb's effectiveness except for short-term weight loss. The agency says the health risks outweigh any benefits.
The Natural Medicines Comprehensive Database says ephedra is "likely unsafe."