Serums can be used to treat a wide range of conditions, including brown spots, wrinkles, and dry or acne-prone skin. Below are the ingredients that Harvard dermatologists Dr. Abigail Waldman and Dr. Maryam M. Asgari recommend for various skin conditions.Problem: Dry or sagging skin If your skin is dry, tight, and flaky, look for serums that contain vitamin E, niacinamide, and glycolic acid. Also look for ceramides, which are fatty molecules that help hold the skin together and keep moisture from escaping. Other good options are serums that contain hyaluronic acid, or those with collagen peptides, epidermal growth factors, or stem cells.Problem: Dark spots or blotchy skin A serum that contains vitamin C, vitamin E, and ferulic acid can help with discoloration. In addition to those ingredients, look for kojic acid (to help lighten dark patches) or glycolic acid (a gentle exfoliant) to help brighten the skin and reduce brown spots. Problem: Acne If youre still plagued with occasional breakouts and acne, youll want to choose a serum with salicylic acid, which helps to unclog pores, and a product with retinol, to reduce inflammation and help prevent pores from clogging.Proceed with caution when it comes to these ingredients Its always important to read the ingredient labels of serums, especially if you have sensitive skin. Some products contain substances that can cause irritation. The American Academy of Dermatology advises people with sensitive skin to avoid skin care products with the following ingredients:Fragrances and preservatives. Many fragrances and preservatives can irritate skin. If possible, use products without them. The least irritating preservatives are parabens, such as methylparaben and butylparaben. These preservatives have been used for more than 80 years and appear to be safe and well tolerated. But parabens bind with human estrogen receptors (although very weakly), and research has suggested possible associations with breast cancer (as well as decreased sperm quality in men). Although other studies havent confirmed the worrisome findings, many manufacturers have removed parabens from their products because of customer concerns. While further study is warranted, the current evidence doesnt support a need to restrict exposure.Botanical or antibacterial ingredients. "Natural" ingredients arent always benign. If you have allergies or sensitive skin, you may find that plant extracts cause a reaction. Antibacterial lotions can also be irritating for some people.Solvents. Chemicals that penetrate the skin include propylene glycol and ethanol. A better alternative is polyethylene glycol, which does not penetrate the skin.Problem: Wrinkles and signs of aging Look for a serum that contains vitamin C, vitamin E, and ferulic acid, a trio of antioxidants that reduce stress to the skin caused by exposure to ultraviolet (UV) light. Research has shown that vitamin C, in particular, has benefits for aging skin, says Dr. Waldman. Vitamin C not only can help decrease skin stress from UV light exposure but is a necessary ingredient in the enzymes your body uses to grow new collagen, so its recommended to stimulate new collagen growth. The addition of the vitamin E and ferulic acid to a vitamin C serum provides your skin with additional antioxidants, and the ferulic acid can also help stabilize the vitamin C. Other good serum options for wrinkles are those containing antioxidants such as tea polyphenols and resveratrol. Retinol, which reduces inflammation is another good option, as is niacinamide, which improves skin elasticity and can soften fine lines and wrinkles.Tip: When buying a vitamin C serum in particular, look for products sold in dark-colored bottles that keep light from getting in, because exposure to light can degrade the ingredients quickly, says Dr. Waldman. In addition, be sure to store your serum in a cool, dry location.Harvard Womens Health Watch