Squalene is an organic compound derived commercially from the liver of sharks and from plants and vegetables oils like olive oil. Squalane is similar to squalene in its structure and function. The primary difference between the two compounds is squalane is more stable and has a longer shelf-life because it doesn't break down as easily. Squalene is converted to squalane to make a more stable compound that can be used in cosmetic and skin care products.
To understand squalane, it's important to know more about its close cousin, squalene, since it has similar properties but is more stable. Squalene is a compound that all plants and animals have and are able to make. It's an intermediate compound in the synthesis of cholesterol, a fat that circulates in the blood. It's also needed to make vitamin D and some hormones that control various bodily functions.
Medically, squalene is used to boost the effectiveness of vaccines. It became the focus of research in the early 1900s when Japanese investigators became intrigued by the fact that sharks don't develop cancer. Sharks that live in deep waters have high concentrations of squalene in their liver that they use to regulate their buoyancy in the water. This inspired Japanese researchers to look at the possible anti-cancer benefits of squalene derived from the liver of sharks. Despite ongoing research in this area, the American Cancer Society says there's not enough evidence to say that squalene from shark liver oil has benefits for treating or preventing cancer.
Squalene is also found in secretions from human sebaceous glands and is a component of sebum. Sebum is a waxy substance secreted by sebaceous glands that helps to protect skin against bacteria and fungi. It also acts as a lubricant and is a good vehicle for enhancing the penetration of other skin care ingredients. To make a more stable compound, squalene is modified to form squalane, the form used in cosmetic and skin care products.
Squalane has emollient properties. Emollients coat the surface of skin and help the skin hold on to moisture. They also soften the skin and smooth its surface, so skin looks and feels healthier. Squalane does this without creating a greasy or sticky feel. In addition, it's also an effective conditioning agent for hair. It conditions by coating and smoothing the hair shaft so that hair feels softer and looks shinier and healthier. Because of its emollient properties and its ability to enhance the penetration of other ingredients, squalane is found in a variety of cosmetic and personal care products including hair conditioners, bath oils, facial cleansers, moisturizers, anti-aging products, make-up foundations, eye creams, concealers, lipsticks and sunscreens.
Is it safe? Squalene is naturally produced by the body, and both squalene and squalane have low toxicity. They're also not irritating to skin and haven't been linked with contact dermatitis or allergic reactions. One problem with products containing squalane is much of the squalene from which it's made comes from sharks. Some species of sharks have been overfished due to the increased demand for squalene and squalane. For this reason, some cosmetic companies are turning to alternative sources for these compounds that doesn't harm sharks. Other sources of squalene for making squalane are olive oil, amaranth seeds, wheat germ and rice bran. These sources are also more acceptable to people concerned about animal welfare. Using shark liver oil as a source has other potential problems. Oils derived from large fish like sharks may contain environmental pollutants and heavy metals that are harmful to humans. Using plant sources is safer, although the yield is lower.
All in all, squalane has benefits as a non-greasy emollient in skin care products and a conditioning agent for hair. It also helps to increase the penetration of other skin care ingredients. Its health benefits in other areas, particularly for the prevention or treatment of cancer are still in question.
Because stearic acid is derived from natural sources and not produced in industrial settings, it is sometimes used as an alternative to chemical ingredients in natural skin care products. It is important to note, though, that often, the ingredient is sourced from by-products obtained during the processing of meats, particularly pork. For this reason, it is not frequently used in vegan cosmetics and skin care products; however, stearic acid sourced from plants is suitable for inclusion in formulas that are animal-free.
The U.S. Food and Drug Administration has concluded that stearic acid is safe for topical use in skin care products in limited quantities. The ingredient is also approved for use as a food additive to give products a chewier or gummier texture. The leading skin care product safety evaluation group, the Cosmetic Ingredient Review (CIR) Expert Panel, has found that the amount of stearic acid commonly used in cosmetics and skin and hair care products does not pose any health risks. Although stearic acid is not toxic, in some clinical studies it has produced skin irritation in rabbits, indicating that some people with sensitive skin may be unable to tolerate the ingredient.