In 2019, a letter from Harvard Health explained that many dietary supplements have hidden pharmaceutical ingredients. It referenced a 2018 study from the Journal of the American Medical Association, which found that 80% of the most common supplements used for sexual enhancement, weight loss or muscle building contain one pharmaceutical ingredient, and 20% have more than one.

A seemingly natural pill isn’t so natural after all. 

Supplement capsules can contain a laundry list of ingredients that should be avoided, yet the products enter the market and are sold across the U.S. It’s imperative to know that supplements with harmful ingredients aren’t black-market items. These supplements are found in everyday stores like CVS, Walmart, Costco and Whole Foods.

According to Consumer Reports, there are 15 toxic ingredients that can cause organ damage, cancer, cardiac arrest and various other concerns.  

Watch out for these 15 ingredients:

1. Aconite is an ingredient that is believed to reduce inflammation, joint pain and gout. It can cause nausea, vomiting, weakness, paralysis, trouble breathing, heart problems and even death.
2. If you struggle with digestion and breathing problems, you may be told to take pennyroyal oil, which can ultimately lead to liver and kidney dysfunction. 
3. Red yeast rice has been recommended for people looking to lower their cholesterol. It has been linked to muscle problems and hair loss. 
4. Caffeine powder is typically taken to enhance attention. However, heart problems, seizures and cardiac arrest can occur, especially if taken with other stimulants. 
5. Chapparal, otherwise known as creosote bush, is taken for weight loss but is also a supplement for colds and rashes. This ingredient contributes to kidney problems and liver damage.
6. Coltsfoot is a supplement taken for coughs, bronchitis, laryngitis, sore throat and asthma. Liver damage is the primary concern with this supplement. Coltsfoot is classified as a carcinogen.
7. Usnic acid, or beard moss, is used when trying to lose weight. It can result in liver damage. 
8. For those who struggle with erectile dysfunction, Yohimbe may be a cure. However, increased blood pressure, seizures, headaches, liver, heart and kidney problems are all possible side effects. 
9. Kava is found in many supplements, as it has gained popularity in tea houses. Said to help ease anxiety and insomnia, Kava can cause liver damage and impaired driving. It can also exacerbate depression and Parkinson's disease.
10. For people seeking weight loss, alleviation of arthritis and gout, Germander can ease concerns. Yet risks involve liver damage, hepatitis and even death. 
11. Comfrey relieves coughs, heavy periods and chest pains but can also cause liver damage, cancer and death. 
12. Green tea extract powder can cause dizziness, ringing in the ears, elevated blood pressure levels and liver damage. It’s used for weight loss. 
13. Methylsynephrine increases energy levels and improves athletic performance, and is typically used for weight loss. Side effects can include cardiac arrest and heart rate abnormalities. Risks increase with the use of stimulants.
14. Lobelia improves respiratory problems but can cause vomiting, seizures, hypothermia, rapid heartbeat, diarrhea and even coma and death.
15. Vinpocetine is a common ingredient that can cause decreased fetal weight and an increased chance of a miscarriage in pregnant women. It’s typically found in products that enhance memory and reduce fogginess, and it is often used for weight loss.

Many types of supplements can also interact negatively with prescription medicine and over-the-counter drugs. In another world, the Food and Drug Administration (FDA) would screen supplements and prevent harmful ingredients from entering the market and human bodies.

How can you stay on top of your health? Read the labels of supplements and eat whole, organic, vitamin-rich foods. Know the side effects of certain supplement ingredients to decrease your chances of adverse outcomes.