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    10 Supplements to Always Avoid

    The risks can be serious, and they increase the larger the dosage and the longer the supplement is taken

    Clear pill on black background with "x" through it Photo Illustration: Chris Griggs/Consumer Reports, Getty Images

    Here are 10 risky supplements that CR, with the help of a panel of doctors and researchers, says you should steer clear of. In general, risk increases the larger the dosage and the longer the supplement is taken. Also beware of illegal or unapproved drug ingredients, such as tianeptine, methylsynephrine, and phenibut.

    Chaparral
    Also Called: creosote bush, greasewood, Larrea divaricata, Larrea tridentata, larreastat.
    Claimed Benefits: weight loss; eases inflammation; treats colds, infections, rashes, cancers.
    Potential Harms: kidney problems, liver damage.

    More on Supplements

    Coltsfoot
    Also Called: coughwort, Farfarae folium leaf, foalswort, Tussilago farfara.
    Claimed Benefits: relieves cough, sore throat, laryngitis, bronchitis, asthma.
    Potential Harms: liver damage, possible carcinogen.

    Comfrey
    Also Called: blackwort, bruisewort, slippery root, Symphytum officinale.
    Claimed Benefits: relieves cough, heavy menstrual periods, stomach problems, chest pain; treats cancer.
    Potential Harms: liver damage, cancer.

    Germander
    Also Called: Teucrium chamaedrys, Teucrium viscidum.
    Claimed Benefits: weight loss; alleviates fever, arthritis, gout, stomach problems.
    Potential Harms: liver damage, hepatitis.

    Greater Celandine
    Also Called: celandine, Chelidonium majus.
    Claimed Benefit: alleviates stomachache.
    Potential Harm: liver damage.

    Kava
    Also Called: ava pepper, kava kava, Piper methysticum.
    Claimed Benefits: eases anxiety, helps sleep.
    Potential Harms: liver damage, exacerbates Parkinson’s disease and depression, impairs driving.

    Lobelia
    Also Called: asthma weed, Lobelia inflata, vomit wort, wild tobacco.
    Claimed Benefits: helps respiratory problems, smoking cessation.
    Potential Harms: nausea, vomiting, diarrhea, tremors, rapid heartbeat, confusion, seizures, hypothermia, coma.

    Pennyroyal Oil
    Also Called: Hedeoma pulegioides, Mentha pulegium.
    Claimed Benefits: improves breathing problems, digestive disorders.
    Potential Harms: liver and kidney failure, nerve damage, convulsions.

    Usnic Acid
    Also Called: beard moss, tree moss, usnea.
    Claimed Benefits: weight loss, pain relief.
    Potential Harm: liver injury.

    Yohimbe
    Also Called: Johimbi, Pausinystalia yohimbe, yohimbine, Corynanthe johimbi.
    Claimed Benefits: treats low libido and erectile dysfunction, depression, obesity.
    Potential Harms: raises blood pressure; causes rapid heart rate, headaches, seizures, liver and kidney problems, heart problems, panic attacks.

    Editor’s Note: This article also appeared in the January 2023 issue of Consumer Reports magazine.


    Head shot of CRO author Lisa Gill

    Lisa L. Gill

    Lisa L. Gill is an award-winning investigative reporter. She has been at Consumer Reports since 2008, covering health and food safety—heavy metals in the food supply and foodborne illness—plus healthcare and prescription drug costs, medical debt, and credit scores. Lisa also testified before Congress and the Food and Drug Administration about her work on drug costs and drug safety. She lives in a DIY tiny home, where she gardens during the day and stargazes the Milky Way at night.