4 Supplements You Shouldn’t Take for Immune Health, According to Dietitians

1. Oregano Oil

If you’ve ever picked up an immunity shot at your local juice shop, you might be surprised to see oregano oil listed as an ingredient. Yes, that oregano, the one we all sprinkle on pizza and pasta. Oregano oil is extracted from its leaves and is available in liquid and capsule form. According to a 2020 article published in Metabolites, oregano oil has been used medicinally for years to treat countless ailments. It is also used as a natural food preservative due to its antioxidant and antimicrobial properties, per a 2019 article in the International Journal of Nutrition. 

 However, human trials are lacking on whether it’s truly effective at supporting health. A 2020 meta-analysis published in Phytotherapy Research primarily examining animal studies showed oregano oil to effectively reduce some inflammatory markers. However, other research, like a 2020 study in the Journal of Virology, showed no effect against fighting the flu. Stick to sprinkling the dried or fresh herb on your food rather than taking a supplement.

2. Colloidal Silver

Colloidal silver is a liquid of tiny silver particles, touted as a cure-all for infections and wounds. However, health experts and the National Center for Complementary and Integrative Health warn against falling for its claims. Kristen Carli, M.S., RD, owner of Camelback Nutrition & Wellness, states, “There are many false claims about the health benefits of taking colloidal silver, particularly that it has antimicrobial properties. There is not enough evidence to support these claims.”

The FDA warns that colloidal silver is unsafe and has neither proven effective nor been used for preventive measures. Carli adds, “I would caution anyone against taking colloidal silver, as it can be harmful in high doses and can negatively interact with many medications.”

3. Echinacea

One of the most popular ingredients you may see in cold and flu products is echinacea. Echinacea is available in just about any form—syrup, powder, throat lozenge, tea bag, capsule and gummy—which makes it so tempting to add one of these products to your shopping cart when your immune system could use a boost.

Echinacea comes from a plant and is hyped for its infection-fighting powers, per the NCCIH. However, Taub-Dix explains, “Some people rely on echinacea, but studies have shown mixed results as to whether it can be relied upon. Moreover, echinacea might interfere with certain health conditions such as autoimmune disorders.”

A 2019 meta-analysis of 29 studies published in Complementary Therapies in Medicine found no significant benefit when echinacea was used to prevent or treat upper respiratory infections. So, it is another one to skip and save from using your hard-earned dollars on.

4. Pre-Workout

Moderate-to-intense exercise may help improve the functioning of your immune system. Still, if you are tempted to take a booster such as a pre-workout before walking out the door, LeBlanc advises using it cautiously toward the end of the day. “Many of them contain caffeine, which might energize your workout, but too much can impact your sleep, leaving you restless and wide awake at bedtime.”

LeBlanc further explains, “Quality sleep is crucial for immune health. It allows your body to rest, repair and fight off illness. Most adults need seven to nine hours a night, so if you’re having trouble sleeping when taking a pre-workout supplement, look for one without caffeine.” Lack of sleep can disrupt the immune system and may increase your risk for not only infections but also metabolic and cardiovascular disorders, per the Centers for Disease Control and Prevention.