Vitamin D3 is not cod liver oil, vitamin D3 is one of the D vitamins, which are fat-soluble. Vitamin D3 can promote intestinal absorption of calcium, can promote the mineralization of bone, promote the formation of bone trabeculae, strengthen the bone. It is often used clinically to treat and prevent osteoporosis, rickets and other diseases caused by vitamin D3 deficiency due to various reasons. Cod liver oil also has vitamin D and vitamin A two components, cod liver oil in addition to the role of vitamin D supplementation, its composition of vitamin A also has the role of protecting the skin and eyesight, but too much vitamin A intake is also easy to accumulate toxicity in the body, resulting in damage to liver function.