15 Supplement Ingredients to Always Avoid

These supplement ingredients can cause organ damage, cardiac arrest, and cancer

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.

IngredientClaimed BenefitsRisks
Aconite
Also called: Aconiti tuber, aconitum, angustifolium, monkshood, radix aconti, wolfsbane
Reduces inflammation, joint pain, goutNausea, vomiting, weakness, paralysis, breathing and heart problems, possibly death
Caffeine Powder
Also called: 1,3,7-trimethylxanthine
Improves attention, enhances athletic performance, weight lossSeizures, 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, cancerKidney problems, liver damage, possibly death
Coltsfoot
Also called: Coughwort, farfarae folium leaf, foalswort, tussilago farfara
Relieves cough, sore throat, laryngitis, bronchitis, asthmaLiver damage, possible carcinogen
Comfrey
Also called: Blackwort, bruisewort, slippery root, symphytum officinale
Relieves cough, heavy menstrual periods, stomach problems, chest pain; treats cancerLiver damage, cancer, possibly death
Germander
Also called: Teucrium chamaedrys, viscidum
Weight loss; alleviates fever, arthritis, gout, stomach problemsLiver damage, hepatitis, possibly death
Greater Celandine
Also called: Celandine, chelidonium majus, chelidonii herba
Alleviates stomachacheLiver damage
Green Tea Extract Powder
Also called: Camellia sinensis
Weight lossDizziness, 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 cessationNausea, 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 performanceCauses 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 disordersLiver and kidney failure, nerve damage, convulsions, possibly death
Red Yeast Rice
Also called: Monascus purpureus
Lowers LDL (“bad”) cholesterol, prevents heart diseaseKidney 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 reliefLiver injury
Yohimbe
Also called: Johimbi, pausinystalia yohimbe, yohimbine, corynanthe johimbi
Treats low libido and erectile dysfunction, depression, obesityRaises 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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