Just like in humans, a sheep's skin has pores that produce oils to hydrate the surface of the body. These oils, called lanolin, have a deep moisturizing effect on human skin and hair. Lanolin is found in cosmetics, skin creams and some moisturizing shampoos. It locks existing moisture into the skin and absorbs additional moisture from the air around it.
Lanolin-based skin creams work well if you have extremely dry skin. Lanolin falls into the lipid-rich emollient class of moisturizers. One of the causes of dry skin is a lack of lipids, which allows water to escape. Lanolin fills in those gaps, preventing future water escape. It is typically mixed with a humectant, which holds moisture to the skin.
Lanolin is one of the ingredients in the most popular lip balms. Its effect is two-fold. The waxy texture allows easy application and even coverage without a mess. This seals the lips and prevents further chapping. Lanolin also absorbs moisture from the air around it, rejuvenating the dry skin tissue and relieving the pain and skin cracking.
People with very curly hair find that regular conditioners do not make the grade. Extra curly hair is typically accompanied by thick hair, which is impenetrable by regular conditioner. Lanolin is thicker and heavier than most other additives to hair products. When massaged into hair, it can provide a softness to otherwise unmanageable hair.
The San Diego County Breastfeeding Coalition recommends that mothers use lanolin as a remedy for chapped and cracked nipples due to breastfeeding. It instructs mothers to gently apply a 2 mm layer of lanolin cream to the nipples and areolas to relieve soreness and skin cracking, which may result as the baby nurses. The lanolin absorbs the humidity in the air, moisturizing the sensitive area. The coalition recommends leaving the lanolin on the nipple while nursing or pumping, as the cleaning and reapplication process will only irritate the skin further. Small amounts of lanolin ingested while nursing will not harm the child.
Jared Paventi is the communications director for a disease-related nonprofit in the Northeast. He holds a master's degree from Syracuse University's S.I. Newhouse School of Public Communication and a bachelor's degree from St. Bonaventure University. He also writes a food appreciation blog: Al Dente.