Horsetail efficacy Security: extracted from plants horsetail drugs basically are considered safe. Horsetail extract. However, when patients have heart or kidney problems due to edema come, should not take horsetail. Horsetail efficacy Brittle nails Anecdotal reports suggest that horsetail may have application in the treatment of brittle nails. This may be because of high content of horsetail silica and silicates, which provide approximately 2-3% elemental silicon. Horsetail extract manufacturers _ Tande Biotechnology (Online) _ horsetail extract provided by the Shaanxi Tande biotechnology company. Shaanxi Tande Biotechnology Co., Ltd. (www.pure-source.cn) (www.zgtdyzt.com) (www.tdyextract.com) is a leader in Xi'an, plant extracts, over the years, the company implement the scientific management, innovation development, the principle of honesty and trustworthiness, and satisfy customer needs. Source world leader in biotechnology with the staff warmly welcome all inquiries negotiations to create the world Biosciences better future.