Most beetroot juice drinks you buy at the store don’t say how much nitrate is in them, and when they do, the numbers are often wrong or missing—so athletes who rely on it for performance don’t know how much to take.

Many beetroot juice bottles don’t say how much nitrate is inside, and when scientists test them, the actual nitrate levels often don’t match what’s on the label—making people doubt the product and messing up science studies.

Many beetroot juices you buy at the store don’t say how much nitrate they have, or if they do, the number on the label doesn’t match what scientists find when they test it—so you can’t trust what’s written, and researchers can’t rely on it for studies.

Not all beetroot juice drinks for athletes have the same amount of nitrate—some have barely any, others have way more—so if you buy one hoping for a certain boost, you might be totally off unless you test it yourself.

Not all beetroot supplements have the same amount of nitrate—some have so little that they probably won’t do anything noticeable for your body, like improve blood flow or exercise performance.

Out of 24 beetroot juice brands tested, only five gave you enough nitrate in one serving to possibly help you exercise better — the rest didn’t deliver the amount scientists think you need.