Phytosterols are natural plant molecules similar to cholesterol. Phytosterols are found in a variety of plants, but are especially abundant in nuts, beans, sunflower, soybeans, and vegetable oils, including hemp, peanut, and canola. Phytosterols are touted for their many inflammatory-relieving properties, and have even been linked to stimulate hair growth and reduce cholesterol. They come in oral supplement form and are also used to make moisturizers and lotions.
Several studies have examined the effects of phytosterols on the skin. A study in Germany had 10 subjects apply different types of moisturizers to their skin, including vitamins, ceramides and phytosterols. Researchers have found that using a moisturizer containing phytosterols and ceramides can prevent the breakdown of collagen in the skin, which occurs when the skin is exposed to sunlight. As you can imagine, years of exposure to the sun's UV rays can cause the skin to lose collagen; therefore, having a moisturizer that reduces this breakdown process can help slow aging. They also found that moisturizers containing phytosterols even had some stimulating effect on collagen production.
Another study found that phytosterols increased collagen and hyaluronic acid production in human fibroblasts; these cells are part of the skin's connective tissue and help repair damaged skin. This is important, why? Hyaluronic acid is a primary humectant, and moisturizing means helping the skin retain moisture.