Joshua Rogers writing for Natural Alternative Remedy explains that horsetail extract powder is used to treat several ailments, including fungal infections, osteoporosis, brittle nails, bronchitis, boils and carbuncles. It is also used to treat diabetes, chilblains, thinning hair, tonsillitis, gingivitis, acne and kidney stones. Horsetail is available as a tea or a pill supplement. Some people apply the ground powder directly to their skin to treat various cuts and infections.
WebMD reports that horsetail is used for jaundice, hepatitis, heavy menstrual periods, frostbite and incontinence as well. According to Rogers, horsetail extract is also available topically in cosmetic and hair care products.
Rogers explains that horsetail absorbs silica from nutrients available in the soil. It is this mineral that makes horsetail extract so appealing. People believe that the silica plays a reconstructive role in many of the structural cells of the human body, including the skin, hair and nails. Horsetail is also believed to contain antioxidants that fight cancer. In a 2004 study, horsetail extract was reported to have decreased edema, a form of fluid retention, in lab mice by 30 percent.
WebMD warns that horsetail extract should only be taken for a short period of time to minimize possible side effects. Women who are pregnant or breastfeeding should avoid the use of horsetail.