Whether a supplement breaks a fast depends on whether it increases resting blood glucose and for how long.

“what breaks a fast is highly contextual. It basically boils down to whether or not something you ingest, whether it be liquid or food, increases your resting blood glucose, how much it increases that resting blood glucose, and how long that increase lasts.”

“In general, if something doesn't contain sugar or much carbohydrate of any kind, it's not going to raise blood glucose very much.”

“Drinking water will not break your fast. Drinking tea will not break your fast. Drinking coffee, provided it is black coffee, will not break your fast. Ingesting caffeine in pill form, will not break your fast.”