Dietary Supplement. Bridging the Gap Between Medicine & Nutrition. Vitamin D3. Calcium. Vitamin A. Vitamin B12. Maximizes Absorption* Provides Essential Nutrients for Maintaining Healthy Bones and Joints, Reducing Your Risk for Osteoarthritis and Osteoporosis*. What is O3? O3 Bone & Joint Essential is a dietary supplement that was formulated to help support the health of your bones and joints by providing essential nutrients that may help enhance your bone and joint quality.* Supplements of both vitamin D and calcium ca.