15 Supplement Ingredients to Always Avoid
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In 2016, with the help of an expert panel of independent doctors and dietary supplement researchers, Consumer Reports identified 15 supplement ingredients that are potentially harmful.
The risks include organ damage, cancer, and cardiac arrest. The severity of these threats often depends on such factors as preexisting medical conditions as well as the quantity of the ingredient taken and the length of time a person has been exposed to the substance.
Many of the ingredients on this list also have the potential to interact with prescription and over-the-counter medications, such as cholesterol-lowering statins and blood-thinning drugs like aspirin and warfarin (Coumadin and generic).
Moreover, our experts agree that none of these supplement ingredients provide sufficient health benefits to justify the risk.
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Ingredient | Claimed Benefits | Risks |
Aconite | Reduces inflammation, joint pain, gout | Nausea, vomiting, weakness, paralysis, breathing and heart problems, possibly death |
Caffeine Powder | Improves attention, enhances athletic performance, weight loss | Seizures, heart arrhythmia, cardiac arrest, possibly death; particularly dangerous when combined with other stimulants |
Chaparral | Weight loss; improves inflammation; treats colds, infections, skin rashes, cancer | Kidney problems, liver damage, possibly death |
Coltsfoot | Relieves cough, sore throat, laryngitis, bronchitis, asthma | Liver damage, possible carcinogen |
Comfrey | Relieves cough, heavy menstrual periods, stomach problems, chest pain; treats cancer | Liver damage, cancer, possibly death |
Germander | Weight loss; alleviates fever, arthritis, gout, stomach problems | Liver damage, hepatitis, possibly death |
Greater Celandine | Alleviates stomachache | Liver damage |
Green Tea Extract Powder | Weight loss | Dizziness, ringing in the ears, reduced absorption of iron; exacerbates anemia and glaucoma; elevates blood pressure and heart rate; liver damage; possibly death |
Kava | Reduces anxiety, improves insomnia | Liver damage, exacerbates Parkinson's and depression, impairs driving, possibly death |
Lobelia | Improves respiratory problems, aids smoking cessation | Nausea, vomiting, diarrhea, tremors, rapid heartbeat, confusion, seizures, hypothermia, coma, possibly death |
Methylsynephrine | Weight loss, increases energy, improves athletic performance | Causes heart rate and rhythm abnormalities, cardiac arrest; particularly risky when taken with other stimulants |
Pennyroyal Oil | Improves breathing problems, digestive disorders | Liver and kidney failure, nerve damage, convulsions, possibly death |
Red Yeast Rice | Lowers LDL (“bad”) cholesterol, prevents heart disease | Kidney and muscle problems, liver problems, hair loss; can magnify effect of cholesterol-lowering statin drugs, increasing the risk of side effects |
Usnic Acid | Weight loss, pain relief | Liver injury |
Yohimbe | Treats low libido and erectile dysfunction, depression, obesity | Raises blood pressure; causes rapid heart rate, headaches, seizures, liver and kidney problems, heart problems, panic attacks, possibly death |
Report It!
If you or someone in your family experiences an adverse event after taking a dietary supplement, report it to the FDA.
Editor’s Note: This article also appeared in the September 2016 issue Consumer Reports. It was updated in October 2019.
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