The idea of a pill that can improve your overall health is an appealing one.

Unfortunately, no matter how colorful their packaging or hopeful their messaging, most vitamins and supplements fall prey to the same problem: We simply do not need them to be healthy. Some supplements – particularly those marketed for physical enhancement – can cause real harm.

However, there are a select few supplements which research suggests may provide certain benefits – especially for people who do not get a particular nutrient in their diet, who may be pregnant, or who do a specific kind of workout. With that in mind, take a look at the supplements you should take – and the ones you should avoid.