Nature's Aid Vitamin D3 400iu is a dietary supplement containing 90 tablets that provide essential vitamin D3 (cholecalciferol) to support bone health, immune function, and calcium absorption. Each tablet delivers a daily dose of 400iu vitamin D3 in an easy-to-take format. Vitamin D3 is crucial for maintaining healthy bones and teeth by promoting calcium absorption. This supplement is particularly beneficial for those with limited sun exposure or increased vitamin D needs. The 90-tablet bottle provides a three-month supply when taken as directed at one tablet daily. As with any supplement, it should be taken as part of a balanced diet and healthy lifestyle.