Early relief of osteoarthritis symptoms with a natural mineral supplement and a herbomineral combination: a randomized controlled trial [ISRCTN38432711].

Background: This study was designed to determine if a natural mineral supplement, sierrasil, alone and in combination with a cat's claw extract (Uncaria guianensis), vincaria, has therapeutic potential in mild to moderate osteoarthritis of the knee.

Methods: Patients (n = 107) with mild to moderate osteoarthritis of the knee were randomly assigned to one of 4 groups; high dose sierrasil (3 g/day), low dose sierrasil (2 g/day), low dose sierrasil (2 g/day) + cat's claw extract (100 mg/day) or placebo, administered for 8 weeks. Treatment was double blinded.