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Supplements That You "Should Avoid," Say Physicians

These supplements can be downright dangerous.
FACT CHECKED BY Emilia Paluszek

Thousands of people end up in hospital every year after experiencing adverse reactions to dangerous supplements. "For many people, a healthy lifestyle means more than eating a good diet and getting enough exercise—vitamins, supplements, and complementary nutritional products are also part of the plan," says Susan Farrell, MD. "But though there is much publicity about their potential benefits, there is less awareness of their possible harmful effects. In fact, using these products can land you in the emergency department." Here are five supplements you should take carefully—if at all. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.



kava kava supplement capsules on brown wooden plate
Shutterstock / Iryna Imago

Kava supplements can be extremely damaging to the liver and should be avoided. "Note that kava has been banned in the United Kingdom and within Europe due to liver toxicity," says Robert D. Ashley, MD. "More than 100 cases of liver toxicity related to the use of kava have been identified, some leading to liver transplant and some leading to death. There are many reasons for liver damage. For one, kava depletes glutathione, a chief antioxidant, within the liver. It also inhibits enzymes involved in the metabolism of many drugs. Many of the cases of liver toxicity were seen in people who had prior liver disease or used alcohol in addition to kava."


Colloidal Silver

Colloidal silver is linked to serious health conditions and should not be taken—or applied—casually. "There are currently no FDA-approved prescription or over-the-counter drugs containing colloidal silver that are taken by mouth," says Wong Siew Wei, MD, at The Cancer Center and Singapore Medical Group. "In 1999, the FDA warned that oral colloidal silver is neither safe nor effective for treating any disease or condition. The silver in colloidal silver products gets deposited into organs such as the skin, liver, spleen, kidney, muscle, and brain. This can lead to argyria, a condition characterized by irreversible bluish looking skin that first appears in the gums."

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"Yohimbe, often marketed as an aphrodisiac and male sexual performance enhancer, is found in more than 550 supplements in the United States," says Harvard Health. "Lesser known is the fact that yohimbe can have harmful side effects, including high blood pressure, anxiety, racing heartbeat, and headaches. At high doses, purified yohimbe can cause heart failure or death."

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Caffeine Pills

Smiling woman taking a pill.

Caffeine supplements can be very dangerous and in some cases, fatal. "​​While consumers of commonly available caffeinated products such as coffee, tea, and soda may be aware of caffeine's less serious effects – such as nervousness and tremors – they may not be aware that these pure and highly concentrated caffeine products are much more potent and can cause serious health effects, including rapid or dangerously erratic heartbeat, seizures and death," warns the FDA. "Vomiting, diarrhea, stupor and disorientation are also symptoms of caffeine toxicity. Pre-existing conditions can intensify the effects of caffeine and make these products even more dangerous for some individuals."

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Don't Think Cannabis Can Prevent COVID-19

Woman with a cannabis leaf in front of her face.

Despite claims to the contrary, there is insufficient evidence that taking marijuana supplements can help prevent COVID-19. "For those who may be hoping for antiviral results from the tiny amounts of CBGA and CBDA found in marijuana, it's helpful to know that heat from smoking, vaping or cooking destroys those two compounds," explain Elizabeth Ko, MD and Eve Glazier, MD. "While CBGA and CBDA may someday play a role in preventing COVID-19, we are years away from a definitive answer."

Ferozan Mast
Ferozan Mast is a science, health and wellness writer with a passion for making science and research-backed information accessible to a general audience. Read more about Ferozan