Calamine is a pink powdery substance that is used both as an active ingredient and as a supporting ingredient in skin care products. The ingredient is made by combining zinc oxide with ferritic oxide. Confusion can arise with the word "calamine," which is also used to describe an ore made up of zinc. In the 19th century, it was discovered that the zinc ore calamine was actually two separate minerals, and since then, the term is not widely employed; however, it is important to note that the ore and the skin care ingredient are not related.
In the early 19th century, solutions that contained zinc were dispensed at pharmacies to treat itching. Although many different zinc compounds were used in these products, the most popular were zinc oxide and zinc carbonate. The latter ingredient gave formulas a yellow color that people preferred less than the pink color found in zinc oxide-based products, and by the middle of the century, calamine was the most widely used anti-itch zinc topical treatment.
For most of the next century, calamine was sold as an over-the-counter product for itching and was mass-produced by a number of manufacturers. In 1992, the U.S. Food and Drug Administration announced that it had the intention of banning calamine and 414 additional ingredients for use in anti-itching skin care products. The announcement explained that the benefits of calamine and these other ingredients were not based on science, and that they were simply ineffective home remedies passed down through generations.
Critics of the FDA's announcement maintained that the benefits of calamine were genuine, and rigorous testing of the ingredient began. In 2008, the FDA formally approved calamine for use in over-the-counter skin care products designed for treating skin irritation based on the results of the testing. The FDA's approval has cemented calamine as one of the most commonly used over-the-counter skin remedies in the world.
Doctors do not fully understand why calamine reduces itching. Some have linked the presence of the phenol, a white crystalline compound, in calamine to its anti-itch properties, but this has yet to be definitively proven through laboratory testing. Although its mechanism of action is not understood, calamine is recommended by doctors for alleviating the itch caused by allergic reactions to toxins in plants like poison ivy, poison oak and poison sumac. Calamine can also reduce the itching of bites caused by mosquitoes and scabies and some types of short-lived infectious diseases that affect the skin like chicken pox. Some people who suffer from eczema also report that calamine helps with itching caused by the condition.
In addition to its ability to lessen itching, calamine is also an astringent, an ingredient that is able to soak up oil and other liquids. When applied to a poison ivy, oak or sumac rash that has begun to seep, calamine absorbs the fluid, reducing the risk of spreading the rash to others. Calamine can also be applied to acne blemishes that are leaking pus and to ulcers, blisters and wounds that are weeping.
Calamine is available in ointments and creams as well as in liquid form. When using the latter, it is important to shake the calamine well and to use a sterile cotton ball or swab to apply the formula, rather than touching the bottle directly to the skin. Any skin rash or sore that does not improve within one week should be evaluated by a physician, even if its itching or seeping is controlled by calamine.
As a supporting ingredient rather than an active one, calamine is found in some cosmetics products. In concealers and foundations, small amounts of calamine may be added to help make redness from acne blemishes and other types of skin irritation less noticeable. Adding calamine to color cosmetics like powdered eye shadows makes them more transparent and easier to layer and blend. Calamine can also be used in clear skin care products and cosmetics to help absorb oil and moisture that can detract from the appearance of the formulas.
Calamine is not known to cause any side effects or to prompt allergic reactions. The ingredient is also not known to interact with any other drugs or medications and is regarded as safe for use by pregnant and nursing women and by children, according to many physicians.