What is Squalene?

The centrophorus artomarginatus deep sea sharks live in waters 600 to 1000 m deep, without sunlight. How can they manage to survive under such harsh conditions, where pressure is consistently high and oxygen supply is very poor?. The secret lies in their livers, which account for 25% to 30% of their total body weight.

In 1906 Dr. Tsujimoto of Japan discovered the shark liver extract, which was later identified as Squalane, with a chemical formula C30H50. Chemically Squalene is an unsaturated hydrocarbon, which can easily produce oxygen by combining with water. Squalene has been extensively researched and, as an oxygen carrier, found to play a key role in maintaining health. Dr Noguchi once said that "the cause of all illnesses is lack of oxygen". A curious trait of the shark is its apparent immunity to cancer and disease. Once regarded as an enemy, a primitive and powerful hunter of the deep, the shark in now being heralded as a lifesaver. This unique fish which has remained structurally unchanged for 400 million years, may provide us with the natural resistance we need to fight many of our most common modern diseases from colds to cancer. Another source of Squalene is olive oil, which has been traditionally known for its health effects. A related compound is Squalane used in skin care products. Squalane is derived from Squalane, but is more stable against oxidation. Other very useful properties of Squalane is its very low coagulation point (-55 degrees Celcius) and very high melting point (203 degrees Celcius), making it very suitable for lubrication.

• Detail description of the properties and uses of Squalene and Squalane can be found in: "Biological Role and Practical Uses of Squalene and Squalane" by Maurice L. Rosenthal in "COSMETICS AND THE SKIN" by I. Lubowe and F.V. Wells, editors Reinhold Publishing Corp., 1964.

Squalene (C30H50)

"The triterpene Squalene is a highly unsaturated aliphatic hydrocarbon (C30H50) which is widely distributed in nature. It is found in small quantities in many vegetable oils, and in larger amounts in certain fish oils. Interest in its medical and cosmeto-dermatological significance was intensified when squalene was found in human sebaceous secretions, as a precursor of cholesterol, and when its possible anti-carcinogenic effect was described. It is the principal hydrocarbon of human surface lipids amounting up to 11 per cent of total surface fat. Its occurrence has been reported in dermoid cysts, cerumen, hair fat, and sebum. In attempting to assign a specific role to squalene in biochemical processes, many interesting developments took place. Squalene, a by-product of natural Vitamin A commercial production, also is converted on its biochemical path to cholesterol sysnthesis, into 7-dehydrocholesterol, which on irradiation becomes Vitamin D. The very limited percutaneous absorption of Vitamin A in enhanced when the vitamin is dissolved in squalene. Studies in relation to its presence in ovarian dermoid cysts and depot fat of women led to its identification in vernix caseosa. It was then postulated that squalene plays an important part in embryological development. Investigation of the fungistatic effect of sebum on skin surfaces led to the observation that certain carcinogenic chemicals are inactivated when exposed to squalene over a period of time. Further studies on patients with epidermoid carcinoma suggested that squalene served as a protective agent in human sebum, as this is the usual type of carcinoma which arises after exposure to carcinogenic hydrocarbons, excessive exposure to sunlight, and ultraviolet rays."

Sebum

"Sebum provides the normal lubricant of hairy and no-hairy skin. It keeps the skin supple and forms a protective bacterial and fungicidal coating on the skin and in the pilosebaceous apparatus. This fatty cover helps to keep moisture on the skin surface." Squalene occurs naturally in the human sebum, as can be seen from the following: "When human sebum was separated from epithelial lipids, its average composition was calculated as follows:"

Penetration through human skin

"The topical application of medicaments to the skin forms the basis of most dermatological therapy. Such application has many advantages, such as absence of pain and of bad taste, simplcity and ease of administration, and high concentration at the desired site. It is the only method by which a high local concentration of drugs in the skin can be achieved without undesirable systemic side-effects.In many instances, it would be advantageous if the rate of penetration of medicaments through the epidermis could be increased. This would help in bringing about a more rapid and profound action of the locally applied compounds. If penetration (transfollicular, transepidermal, and into the horny layer) could be increased, many new compounds could be introduced into therapy. Hence, the importance of sebum and its main hydrocarbon squalene in cosmeto-dermatological field. The commercial use of this unique hydrocarbon was, therefore, a forgone conclusion."

Squalane (C30H62)

"This commercially available product is a colorless, odorless, tasteless, transaparant, stable, inert, homogeneous liquid oil." "On the basis of numerous clinical tests, it has been concluded that squalane is a bland vehicle, with the unusual property to increase the rate, depth, and extent of penetration of topical agents from medicated ointments. On the other hand, squalane does not aid transepidermal penetration, nor dissolve the cementing substance of the horny layer." "The cosmetologist has found in squalane a natural emolient. It imparts to the skin a suppleness without an unpleasant greasy feel. It readily forms emulsions with fixed oils and lipophilic substances and does not oxidize nor turn rancid. Squalane has also been found to accelerate dye-dispersion in lipsticks, producing a high gloss and acting as a long lasting fixative for perfumes. When applied to wshed or sun exposed skin and hair, squalane helps to restore the lost oils. It has long been known that coating the skin with oils offers considerable protection from sunburn because of a strong absorption band in the erythemogenic region"

Cosmetic Ingredient Review

Final Report on the Safety Assessment of Squalane and Squalene

Summary

Squalane and Squalene have been identified as a natural components of human sebum. Both ingredients are used at concentrations ranging from =< 0.1 to >= 50 percent in a variety of cosmetics. Because cosmetics containing Squalane and Squalene are applied to all body surfaces, these compounds may potentially enter the body through the skin, eyes, lungs, mouth, or other routes. Squalene can form peroxides on exposure to air, while Squalane is stable to air and oxygen. Animal studies indicate Squalane is slowly absorbed through the skin, while both compounds are poorly absorbed from the gastrointestinal tract. Squalene is a metabolic precursor of cholesterol and other steroids. The acute toxicity of these ingredients by all routes in animals is low. At 100 percent concentrations, both compounds are nonirritants to rabbit skin and eyes. According to clinical evidence of formulations containing Squalane, the compound is not a significant skin irritant or sensitizer. Limited contact sensitization tests indicate that Squalene is not a significant contact allergen or irritant. Reversible depilation is reported from topical application of Squalene to animals, but limited human studies did not show any such effect. No photosensitivity data for the two ingredients were available.

Conclusions

On the basis of the available information presented in this report, The Expert Panel concluded that both Squalane and Squalene are safe as cosmetic ingredients in the present practice of use and concentration.