This means that once your body gets used to you consuming caffeine, it shouldn’t cause health problems related to hormones, but that doesn’t mean drinking it on an empty stomach is good for you. Coffee makes your stomach acid increase, so if you drink it on an empty stomach, it may cause heartburn or indigestion. In addition, caffeine in general can trigger gastritis and other stomach issues. “Large amounts of caffeine are not advised for people with hypertension, heart arrhythmias, kidney or liver diseases, and anxiety.”

“Also, some people may be particularly sensitive to coffee, which could lead to painful periods or be an acne trigger. If you feel this is the case for you, then it wouldn’t hurt to trial a week or two without coffee to see what happens. There are some medical scenarios in which regular coffee consumption may pose an issue, so it’s always best to check with your doctor,” he said.

Source: https://www.buzzfeed.com/kristatorres/coffee-on-empty-stomach