Betaine Nitrate side effects?

At the levels presented in the studies mentioned above, as well as the dosage that is in the Nitramine pre workout supplement (2g per scoop), no side effects could be shown.
Previous studies involving other medical deficiencies have used far higher dosages of betaine, and the most common side effect is nausea, but its occurrence rate is low. Those using the trimethylglycine hydrochloride (a version not used in most muscle-building supplements) also have a higher rate of heartburn.
Food-based sources
Popeye was right – Spinach is a betaine sourceThe name is actually due to the fact that it was first found in beets. Beet root is actually quite high in betaine nitrate. Many supplements use beet root extract to provide a form of betaine, but the anhydrous form (without water) is pure and will give the highest concentrations.