The FDA regulates dietary supplements, but it treats them like foods rather than medications. Unlike drug manufacturers, the makers of supplements don’t have to show their products are safe or effective before they sell them.
This is a sugar that comes from the hard outer layers of lobsters, crabs, and shrimp. Enthusiasts say it can block fats and cholesterol from getting absorbed by your body.
Does it help you lose weight? Natural Medicines, an independent group that analyzes research on supplements, says there isn’t enough reliable evidence to rate it. The National Center for Complementary and Integrative Health states that chitosan has not been shown to be effective for weight loss.
There are claims that chromium supplements can:
- Lower your appetite
- Help you burn more calories
- Cut your body fat
- Boost your muscle mass
But a review of 24 studies that checked the effects of 200 to 1,000 micrograms of chromium a day found that there aren’t any significant benefits. Natural Medicines says that chromium is “possibly ineffective” for weight loss.
At less than 35 micrograms a day, chromium supplements are typically safe for adults. Higher doses can cause:
Conjugated Linoleic Acid (CLA)
This is a popular supplement that contains chemicals found in a fatty acid called linoleic acid. There are claims that it may help curb body fat and help you stay full.
The research on CLA for weight loss is mixed. Some suggest that for some people, 1.8 to 6.8 grams of CLA per day may:
- Curb body fat
- Boost muscle
But other research shows it doesn’t help you shed pounds.
Natural Medicines says that CLA is “possibly effective” for weight loss.
Some researchers warn that long-term use, especially if you’re obese, may raise insulin resistance, which makes it more likely you’ll get type 2 diabetes. It might lower “good” cholesterol in your blood, as well, which raises the risk of heart problems.
In some people, CLA may cause side effects such as:
This is made from the konjac plant. Like other dietary fibres, it’s supposed to help you lose weight by blocking fat in your food from being absorbed into your body.
Very early studies suggest it might be helpful, but other evidence shows it doesn’t work.
Natural Medicines says there is “insufficient evidence” to rate how well glucomannan works for weight loss.
If you take glucomannan in the tablet form of the supplement, you could choke or get a blockage in your:
It appears to be somewhat safer if you take this supplement as a powder or a capsule.
Glucomannan also may make it harder for your body to absorb medications. So take your medicine either 1 hour before or 4 hours after you use glucomannan.
Green Tea Extract
It supposedly works by:
- Curbing your appetite
- Raising calorie and fat metabolism
Natural Medicines says there isn’t enough evidence to rate how well it works.
Side effects of green tea extract, especially in high amounts, include:
Green Coffee Extract
Early studies suggest it may lead to modest weight loss, but more research is needed. Natural Medicines states that there is not enough good research to decide if it is effective.