Supplements are a multi-billion dollar industry, and unlike prescription medications, are not regulated by the U.S. government. I do take supplements, primarily vitamins and minerals. I take a senior multivitamin as an insurance measure. I also take an iron supplement due to restless leg syndrome (it's recommended to keep ferritin above 70.) and Vitamin D because I live in the northern latitudes. When I started tracking food intake using the Cronometer nutrition app, I added more supplements where I fell short on the daily basis. I also take a 5 mg creatine supplement to maintain muscle mass, in addition to doing resistance exercises.

Because supplements are not regulated, it is hard to know if the amount listed on the vial is what you're getting. There are agencies like USP that manufacturers can have test their products and give the USP seal of approval to. I have a subscription to Consumer Labs, which does a good job of test supplements are accurately labeled for amount, heavy metal contaminants, etc. I've found them to be a good source for confidently selecting supplements.

Dietary supplementation is a money pit. I always see what appears to be a logical reason to add something to the list and rarely eliminate anything. And of course supplements can interfere with the actions of prescribed medications. My primary care doctor has a list of all the supplements I take.