Allantoin is a compound found in the urine of most mammals with the exception of human and primates. Mammals other than humans and primates convert uric acid, a chemical produced when purines are broken down, to allantoin, which is then excreted through the urine. Humans and primates lack the enzyme that converts uric acid to allantoin, so uric acid is excreted instead. When uric acid isn’t eliminated quickly enough through the kidneys, it builds up in the bloodstream. This can lead to a common condition called gout. Allantoin can also be extracted from the comfrey plant, an herbal plant known for its medicinal benefits or produced synthetically by oxidizing purines.
Like the comfrey plant, allantoin is recognized by herbalists as having medicinal value. Herbalists use it to treat psoriasis, a chronic skin condition characterized by inflammation and reddened patches of skin with silvery scales. It may be effective for treating other skin conditions as well. One study showed that a topical cream containing allantoin was effective for treating itching associated with atopic dermatitis. This isn’t surprising since allantoin has anti-inflammatory properties and the ability to ease skin irritation. It also acts as an emollient, helping to soften skin and smooth dry, irritated skin.
Creams and ointments containing allantoin are used to treat skin conditions like diaper rash in babies, wind burned skin from exposure to cold, sunburned skin from overexposure to the sun, chapped lips and to ease the discomfort of cold sores. Allantoin can also be applied to scrapes, burns and cuts as a way to soothe and protect the area. It also appears to speed up wound healing by stimulating new skin cell growth and is sometimes used to treat radiation skin burns in people who are undergoing radiation treatment for cancer. Allantoin is available as a shampoo combined with coal tar to treat scalp psoriasis, seboorhea, dandruff and eczema involving the scalp.
Because of its anti-inflammatory properties and its ability to soothe skin irritation, allantoin is an ingredient in some cosmetic and personal care products. In skin care products, allantoin helps to moisturize and soften skin and acts as a keratinolytic. Keratinolytics soften keratin, a tough, inflexible protein found in the outer layer of the skin called the epidermis. By softening keratin, allantoin allows skin to hold onto water better. This makes it moister, softer and better hydrated. Keratinolytics also dissolve the material that holds skin cells together. This enables the outermost layer of skin cells to shed or slough off more easily, creating a smoother skin surface. Allantoin not only reduces skin irritation, it also moisturizers and improves the texture of skin.
A wide range of cosmetic, skin and personal care products contain allantoin as an ingredient. These include sunscreens, lip balm, lipsticks, moisturizers, body lotions, eye creams, toothpaste, mouthwash, acne treatments, toners, hand creams, shaving cream, bath products, baby powders and hair gels. These products usually contain allantoin concentrations between 0.5% to 2.0% percent.
Is it safe? Allantoin appears to be safe in the amounts added to cosmetic, skin and personal care products. The Environmental Working Group Skin Deep database classifies it as a low hazard cosmetic ingredient. It has not been linked with health problems and doesn’t accumulate in the environment. It’s also unlikely to cause allergic reactions or skin problems due to its anti-inflammatory properties and its ability to soothe skin irritation. Allantoin appears to be safe for skin and for overall health.
Although allantoin is safe when used topically, allantoin and extracts from the comfrey plant shouldn’t be used orally since they can cause liver damage. At one time, comfrey was used to treat digestive problems until it was discovered the plant contains pyrrolizidine alkaloids that are liver toxic.
In summary, allantoin is a safe cosmetic ingredient when used topically in the amounts found in cosmetic and personal care products. It has emollient properties that help skin retain moisture, and it reduces skin irritation from a variety of causes. Because it’s a keratolytic, it can improve skin texture, making it feel smoother and reflect light better. It may also be beneficial for treating some skin conditions including psoriasis and eczema.
Environmental Working Group Skin Deep Cosmetics Database. “Allantoin”
Truth in Aging. “Allantoin”
J. Drugs Dermatol. 2009 Jun; 8(6): 537-9.