Mini: Which types of supplements lead the pack for serious adverse events in the U.S.?
Many supplements have some side effects, but there are a small handful that can cause more trouble than others. We summarize the findings of recent research taking a look at the worst offenders.
Last Updated: April 28, 2021
Become an Examine+ member to get full access to the Examine Database, Study Summaries, and Supplement Guides.
Try for free for 7 days and stay on top of the latest research.
One of the main ways to gather data about nutritional supplement safety is to monitor supplements after they come to market. In the U.S., the Dietary Supplement and Non-Prescription Consumer Protection Act requires that supplement manufacturers report any serious adverse events (SAEs) to the FDA within 15 days of finding out from customers or health care professionals. An SAE is technically defined in the Food, Drug, & Cosmetic Act as an event that “(r)esults in death, a life-threatening experience, inpatient hospitalization, a persistent or significant disability or incapacity, or a congenital anomaly or birth defect; or requires, based on a reasonable medical judgement, a medical or surgical intervention to prevent an outcome described above”. In short — SAEs are indeed serious!
A team of researchers took advantage of the requirement for supplement manufacturers to systematically collect and report SAEs by monitoring the SAEs reported to two large supplement manufacturers based in the U.S. over 2.5 years. They did this in order to determine which supplements caused the most problems, what kinds of problems were caused, and to get an estimate of how many of the problems supplements caused were major ones. Their findings were published[1] in December of 2018.
Around 41,000 adverse events were reported over the 2.5 years monitored by the researchers, and around 0.5% of these were SAEs. Since we don’t know how many people took the supplements, it’s hard to say how common adverse effects were overall. However, this study does allow an estimation of what types of supplements are most linked to serious adverse effects, and how those effects usually manifest. In the table below, we summarize the main findings for the top three supplements linked to SAEs.
This study can’t tell exactly which ingredients were the main culprits, in part because many of these supplements are combinations of several ingredients. However, one clear take-home message is that weight and fat loss supplements are the biggest offenders as a class, accounting for around 70% of all serious problems.