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 pre-existing 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. Even so, we found all 15 ingredients in products available online or in major stores such as GNC, Costco, CVS, Walmart, and Whole Foods. (Download this PDF to find out more about how we selected these ingredients, our panel of dietary supplement experts, and how we shopped for products.)
| INGREDIENT | CLAIMED BENEFITS | RISKS |
| Aconite Also called: Aconiti tuber, aconitum, angustifolium, monkshood, radix aconti, wolfsbane |
Reduces inflammation, joint pain, gout | Nausea, vomiting, weakness, paralysis, breathing and heart problems, possibly death |
| Caffeine Powder Also called: 1,3,7-trimethylxanthine |
Improves attention, enhances athletic performance, weight loss | Seizures, heart arrhythmia, cardiac arrest, possibly death; particularly dangerous when combined with other stimulants |
| Chaparral Also called: Creosote bush, greasewood, larrea divaricata, larrea tridentata, larreastat |
Weight loss; improves inflammation; treats colds, infections, skin rashes, cancer | Kidney problems, liver damage, possibly death |
| Coltsfoot Also called: Coughwort, farfarae folium leaf, foalswort, tussilago farfara |
Relieves cough, sore throat, laryngitis, bronchitis, asthma | Liver damage, possible carcinogen |
| Comfrey Also called: Blackwort, bruisewort, slippery root, symphytum officinale |
Relieves cough, heavy menstrual periods, stomach problems, chest pain; treats cancer | Liver damage, cancer, possibly death |
| Germander Also called: Teucrium chamaedrys, viscidum |
Weight loss; alleviates fever, arthritis, gout, stomach problems | Liver damage, hepatitis, possibly death |
| Greater Celandine Also called: Celandine, chelidonium majus, chelidonii herba |
Alleviates stomachache | Liver damage |
| Green Tea Extract Powder Also called: Camellia sinensis |
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 Also called: Ava pepper, kava kava, piper methysticum |
Reduces anxiety, improves insomnia | Liver damage,exacerbates Parkinson’s and depression, impairs driving, possibly death |
| Lobelia Also called: Asthma weed, lobelia inflata, vomit wort, wild tobacco |
Improves respiratory problems, aids smoking cessation | Nausea, vomiting, diarrhea, tremors, rapid heartbeat, confusion, seizures, hypothermia, coma, possibly death |
| Methylsynephrine Also called: Oxilofrine, p-hydroxyephedrine, oxyephedrine, 4-HMP |
Weight loss, increases energy, improves athletic performance | Causes heart rate and rhythm abnormalities, cardiac arrest; particularly risky when taken with other stimulants |
| Pennyroyal Oil Also called: Hedeoma pulegioides, mentha pulegium |
Improves breathing problems, digestive disorders | Liver and kidney failure, nerve damage, convulsions, possibly death |
| Red Yeast Rice Also called: Monascus purpureus |
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 Also called: Beard moss, tree moss, usnea |
Weight loss, pain relief | Liver injury |
| Yohimbe Also called: Johimbi, pausinystalia yohimbe, yohimbine, corynanthe johimbi |
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 |