Vitamin A is the "skin vitamin," relieving various types of problems. Vitamin A is especially helpful in treating acne and also helps protect the body from toxins, such as tobacco smoke. Vitamin A has also been shown to help prevent cancer.

Because you can actually overdo vitamin A, the safe form to take is beta-carotene, a preliminary form of vitamin A. To increase beta-carotene in your diet, eat orange and yellow vegetables and fruits. Or take 10,000 IU of beta-carotene daily.

Vitamin B is called the "antistress vitamin." B-complex nurtures the nervous system and adrenal glands. Take it when you're dealing with emotional or physical stress. The B's also improve memory. The amounts of vitamin B vary in multivitamins. Take between 25 and 50 mg of all the B's, with the exception of folate (400 mcg) and B12 (100 mg).

Vitamin C is the "anti-infection vitamin" and is well-known for fending off colds and other infectious diseases. Vitamin C also reduces inflammation and builds tissue after muscle strain or other injury. The suggested amount varies, but 500 mg a few times a day until you feel better should be sufficient. (To absorb the vitamin better, take several smaller doses spread out throughout the day rather than a high dose at one time.)

Vitamin E helps reduce acne outbreaks. Teens with skin trouble can take 200 to 400 IU a day. Vitamin E also improves blood circulation and acts as an antioxidant, which is especially important if your teens are involved in any type of physical activity.

Evening primrose oil, like vitamin E, helps balance hormones and reduces acne. It also helps relieve PMS symptoms, breast cysts, and menstrual pain. However, before seeing results, teens need to take 500 mg one or two times a day for a couple of months.

Pantothenic acid, a member of the B-vitamin complex, decreases sebum secretion, which contributes to acne. Take 200 mg twice a day or apply pantothenic acid cream directly to problem skin. In addition, this supplement reduces hay-fever symptoms.

—K.K.