__[Vitamin D](https://ul.orna.me/KOge/librarybiomarker?id=187)__ is a precursor to a hormone that takes part in many body processes. The most known is the regulation of phosphorus-calcium metabolism. In addition, it helps to resist infections as well as the development of cardiovascular, oncological, and autoimmune diseases. Vitamin D is produced in the skin by exposure to sunlight. This is facilitated by ultraviolet radiation with a wavelength of 320–400 nm — therefore, visiting a solarium ===or sunroom will not help replenish the level of vitamin D! Food is also rich in Vitamin D including high-calorie fish, fish oil, egg yolk, and dairy products. ## When did vitamin D become popular? The first wave of vitamin D popularity happened in the second half of the 20th century when doctors strongly recommended it to pregnant women and children. This contributed to a significant decrease in the incidence of hypovitaminosis, but in some patients, it led to taking too much. Cases of miscarriage, development of microcephaly associated with premature closure of the fontanelle, and slowing of the growth of the skull bones have become more frequent. In some children, clinical and electrocardiographic changes in the cardiovascular system were manifested not only at the height of intoxication, but even as long as 5–7 years after the disease, which indicated the presence of serious morphological changes. Doctors sounded the alarm, and articles began to appear on the problem of vitamin D overdose. It was found that it is not possible to get too much vitamin D from the sun since the body has its own protection and the excess vitamin gets destroyed. However, in the case of excessive intake of dietary supplements and drugs with vitamin D, it is possible to “go over” the limit. ## How do you know if you have too much vitamin D? During the pandemic, vitamin D and active vitaminization have been trendy again. While an adequate level of vitamin D is clearly needed, a level that is either too high or too low is associated with an increased risk of developing pathological conditions — for example, certain types of cancer and premature aging. Too much vitamin D can cause weight loss, increased fatigue, nausea, headaches, constipation, polyuria, progressive dystrophy, renal dysfunction, and pathological changes in the cardiovascular and nervous systems. ## How much vitamin D should you get? For prophylaxis, 400 IU–600 IU of vitamin D is recommended per day. If a deficiency occurs (confirmed by analysis for 25-OH), your doctor will select a therapeutic dosage based on your individual characteristics. After normalizing the level of vitamin D, it will be possible to return to the prophylactic dose and pause it in sunny months. Before prescribing and during treatment with high doses of vitamin D, it is necessary to control the level of calcium in the body. For the convenience of tracking the dynamics of results, you can use Ornament. You should not self-medicate—only a doctor can prescribe medications, including vitamins.