There are thousands of vitamin manufacturers in the United States. There are pills and capsules, liquids and powders. They come in boxes, bottles, pill packs and pouches.

With so many options, it can feel impossible to know which brand to choose. What makes one better than another? The Food and Drug Administration doesn’t evaluate dietary supplements before they go to market, which means there’s little oversight over their effectiveness and safety. It’s also unclear if vitamins actually contain the ingredients they claim to ― and many studies have found there are major discrepancies between what’s in the pill and what’s listed on the packaging label.

As a result, there’s no easy way to determine what’s top-notch. “You can’t look at a bottle and price and say, ‘OK, this is low-quality because it’s cheap,’” said Mahtab Jafari , a professor of pharmaceutical sciences at the University of California, Irvine School of Pharmacy & Pharmaceutical Sciences. That said, there are a few things to keep in mind when shopping for a good vitamin.

Here’s what you should consider: What even makes a vitamin expensive? Generally speaking, there’s likely little difference between a cheap vitamin and an expensive one, according to Ebne Rafi , a clinical pharmacy specialist at University Hospitals in Ohio. Prices vary based on what the supplement is, what the ingredients are, and what health condition it’s designed to help. Factors like nice packaging may also come.