Nitric oxide breaks down too fast in the body to be taken as a pill or swallowed—it has to be made inside the body using other substances because it disappears in less than two seconds.

The study didn’t give people nitric oxide gas to swallow, but it did use a chemical that releases nitric oxide in the body — and it worked. This supports the idea that you can’t just swallow nitric oxide because it falls apart too fast, so you need a workaround.

The study found that nitric oxide disappears from body tissues in less than 2 seconds — so short-lived that you can’t just swallow it and expect it to work. This matches the claim that it needs special pathways to be useful in the body.