We have come across no scientific evidence to suggest that whey protein concentrate causes acne. However, some people may be more susceptible to breakouts when they consume whey protein powder because of high levels of lactose. If you can have breakouts, you may consider using a whey protein isolate, which is lower in lactose and may be better tolerated by your skin. You can also try using a plant-based protein powder, which is less likely to cause breakouts. If you experience breakouts after consuming whey protein powder, it is important to talk to a dermatologist or skin care professional.