Does taking supplements break a fast?

According to Andrew Huberman, whether a supplement breaks a fast depends primarily on its impact on your blood glucose levels. For most supplements that do not contain significant amounts of carbohydrates or sugars, such as fish oil or Athletic Greens, there is no substantial effect on blood glucose, and therefore, they do not typically break a fast. Similarly, other supplements that fall into this category, provided they lack sugar or carbohydrates, should also not significantly affect fasting 1.

In the case of artificial and plant-based sweeteners, like Stevia, the effect on blood glucose can vary. Some artificial sweeteners may cause a transient increase and then decrease in blood glucose levels. However, non-sugar sweeteners, particularly when consumed in moderation, tend to have minimal impact on overall blood glucose levels. This suggests that their use during a fast would not generally be considered as breaking the fast, although individual responses can differ 2.

Therefore, the key factor in determining if a supplement breaks a fast is whether it causes a significant response in blood glucose levels.