3 Rare But Serious Side Effects of Vitamin B12 Supplements Is your B12 supplement causing your breakouts? It sounds like a paradox: you take vitamins to be healthy, but your skin starts acting up. While Vitamin B12 is essential for your Is B12 making you break out? It's possible. We've found in our own experience and in clinical studies that certain forms of vitamin B12 can trigger inflammatory acne for some individuals. Hot take: The skincare world told you vitamin b12 causes acne but yet your skin, brain, and hormones literally need it to function and everyone forgets to mention it's essential for detox,