Taking betaine supplements can boost the amount of betaine in your blood by more than three times, which means your body easily absorbs and uses it.

Taking betaine supplements doesn't change the levels of amino acids in the blood of healthy, active guys, which means it doesn't really mess with how their bodies use or balance proteins.

Taking betaine supplements may raise levels of betaine and some related compounds in your blood, slightly increase your 'bad' cholesterol, and lower a harmful substance called homocysteine — but it’s not clear if this is good or bad for your health.

Taking betaine, a natural compound found in foods like beets and spinach, can slightly lower a substance in your blood called homocysteine—which, when too high, might be bad for your heart. This suggests betaine helps your body process certain nutrients better.

Taking betaine supplements doesn't change the level of choline in your blood, which means your body doesn't use betaine to make or use choline right away.

Taking betaine supplements for a few months might raise your 'bad' cholesterol a little bit—about 5 points—which could cancel out the heart benefits you get from lowering another blood chemical called homocysteine.