Question: what is the best vitamin for stiff joints?
Answer: Vitamin D. The number one supplement I recommend for joint health and overall musculoskeletal health is vitamin D3. ... 
Estrogen. Estrogen is important for musculoskeletal health, including joint health. ... 
Glucosamine and Chondroitin Sulfate. ... 
MSM. ... 
Turmeric. ... 
Omega 3. ... 
Ginger. ... 
SAMe.