Acne breakouts occur when the sebaceous glands at the base of hair follicles secrete too much sebum, an oily substance necessary for lubricating skin. Excess sebum can block the pores, leading to blemishes, blackheads and pimples. Hormonal imbalances, stress, certain medications and heredity are common causes of this unsightly condition. Vitamin A is involved with regulating sebum production and has had some success in controlling acne. Vitamin B6 and magnesium help balance hormone levels that could be triggering outbreaks. Vitamin C and zinc boost the immune system and may help kill the bacteria that causes acne. Vitamin E is important for skin repair and selenium helps with skin elasticity. Flaxseed oil and evening primrose oil contain gamma-linolenic acid, which can dilute oily sebum to reduce the chance of pore clogging. Finally, topical applications of astringent tea tree oil can dry up blemishes.