A shampoo. Essentiel Solid Biome-Friendly Shampoo is a cleansing solid shampoo that respects the microbiome. This shampoo is made with 86% natural ingredients that cleanse the hair effectively and gently. It is enriched with a microbiome-friendly herbal complex (patchouli and organic sage) and a castor oil extract, which help to strengthen and revitalize the hair ecosystem.