Taking L-citrulline supplements every day for a few weeks might slightly lower your blood pressure—like a small drop that could help keep your heart healthier.

Taking at least 6 grams of L-citrulline every day might lower your bottom blood pressure number by about 3 points, but taking less than that doesn’t seem to do anything noticeable.

Taking L-citrulline pills or getting it from watermelon might help lower your blood pressure a little—especially if you already have high blood pressure and take it for at least six weeks.

Taking L-citrulline pills for 10 days at a specific dose doesn’t seem to make healthy young adults feel sick—only a few people might get a little stomach upset.

Taking a specific dose of L-citrulline for 10 days doesn’t make you bike harder, faster, or feel less tired—even though some people think it might help. Your heart, lungs, and muscles act the same as if you didn’t take it.