Acne isn’t just the result of poor cleansing habits or excessively oily skinit can also result from how you treat your body as a whole. “Stress, unhealthy eating habits, and lack of exercise are the most common culprits causing acne,” Dr. Ostad said. “It is important to limit processed sugar and be gentle to your skin to avoid adult acne." He also points out how several studies have shown that cows’ milk can increase adult acne, though soy or nut milks, as well as cows' cheese or yogurt, don't pose the same risk.
"A recent study also showed that fish can help prevent acne, which is why I like all my acne patients to take fish oil high in Omega-3 fatty acids," he added. "A low glycemic index diet—think the Mediterranean diet—can also help prevent or improve acne.” TRY: Obagi CLENZIderm Daily Care Foaming Cleanser ($22, obagi.com for locations); Burt’s Bees Clarifying Toner ($10, burtsbees.com); LaRoche -Posay’s Effaclar Mat ($31, laroche-posay.us ); and Kate Somerville’s Eradikate Acne Treatment ($22, sephora.com).Read MoreLess