There are two main sources of vitamin D. The first is sunlight, which stimulates the skin cells to make vitamin D. The other is from food. The other way is from food. But whether it’s made in the skin or eaten, vitamin D is not functional and needs to be further processed by our liver and kidneys to become truly active. Vitamin D is so important that some older people have started taking vitamin D supplements such as cod liver oil and deep sea fish oil, as well as medicines containing vitamin D such as Alpha Osteogenol and Rogaine. These are certainly good for bone health, but is it true that the more vitamin D supplements or drugs you take, the better? The answer is still no. Because the bones in our body are in a constant state of metabolic change, and the key to determining whether the bones become hard or loose is two cells: osteoblasts and osteoclasts. Osteoblasts are like a “construction worker”, constantly “building bricks and walls” to make our bones stronger and stronger, and osteoclasts are like a “demolition worker”, constantly The osteoclasts are like a “demolition worker”, constantly “chiseling and knocking”, making the bones looser and looser. The function of osteoblasts in a child’s body is much greater than the function of osteoclasts, so a young child with tender bones slowly grows into a young adult with strong bones. And when you get older, things are reversed, the function of osteoblasts in the bones is much greater than the function of osteoclasts, so the bones of the elderly are getting looser. However, studies have now found that excess vitamin D enhances the function of osteoclasts and inhibits the function of osteoblasts. Therefore, taking too much vitamin D supplements or drugs will not make your bones stronger, but on the contrary, your bones may become more lax. What can be done? It would be good if we could know if there is a vitamin D deficiency in our body. If it is deficient, we should supplement it, if not, then we should not blindly eat which contains vitamin D supplements or drugs, that would be better? Now many large hospitals can test for vitamin D. Our hospital’s experimental medical center is also available for testing. I recommend that patients have their vitamin D tested before applying calcium and vitamin D. After starting treatment, vitamin D is also tested every 3 to 6 months, so that clinical treatment can be better guided. Adults: osteoblasts = osteoclasts Children: osteoblasts > osteoclasts Elderly: osteoclasts > osteoclasts