But to further sort out fact from fiction about apple cider vinegar and acne, we took a look at the current scientific research and asked experts for their take. Use one-part vinegar to three or four parts water (for sensitive skin types, even more water). Additionally, “before using it on your face for the first time, it’s a good idea to try a test spot on your skin to make sure you won’t have an adverse reaction,” Barr says.