Vitamin K is needed for the production of prothrombin in the body, which is very important in the process of blood clotting. In a shortage situation the blood does not clot at all or clot very slowly. It is a natural medicine in many diseases, for example, intestinal inflammation, stones in the kidney, pancreatic or liver cancer. It also helps to treat ailments such as nausea and vomiting. It also plays an important role in the calcium economy. It regulates bone metabolism, which helps in the prevention and treatment of osteoporosis. Hypervitaminosis can cause excessive sweating and feeling of heat. Despite the fact that it is stored in our body in small amounts we quickly feel its deficiency, which is why proper supplementation is important. Vitamin K is one of the most important vitamins in the athlete's diet and we cannot ignore it. This is because it prevents calcification of the veins and protects bones from damages. It sometimes behaves like a hormone and stimulates genes to produce an important protein, i.e. collagen. This is especially important for muscle performance and strength. During reduced aerobic comfort (various physical exertions), it supports the proper course of energy processes. Supplementation with vitamin K in athletes and the elderly maintains the normal state of muscle tissue. Muscle tissue does not store vitamin K like the liver, which is why the supplementation shows broad pro-health activity.