One case study on postmenopausal vertebral fracture found that taking 680 mg of strontium chloride daily for over two years increased bone mineral density in one person.[1] Otherwise, clinical evidence largely focuses on the use of strontium ranelate for bone health. In the US, strontium supplements are available for adults and children over the age of 4 and can range from 0.01–2,000 mg per day.[2]
For hypersensitive teeth, pastes containing 2–10% strontium chloride or 8% strontium acetate (twice per day in normal brushing habits) have shown some success.[3][4][5][6][7][8][9][10][11] However, as an ingredient, it has largely been abandoned in dental sensitivity pastes and replaced by other desensitizers, so it may be difficult to find over the counter in some countries.