Studies on the effects of sex on the human body and mind reveal a vast amount of data on the benefits of this pleasurable activity. The scientific method is also supported by a strange statement – intimate contacts can increase the defenses of the immune system. Making sexual contacts 1-2 times a week is the optimal frequency needed to increase the body’s immune power. The claim is based on a popular study published in 2004 in the journal Psychological Reports by scientists Carl Charnetsky and Francis Brennan. The strength of the immune system can be precisely determined by measuring antibodies known as immunoglobulin-A (IgA) present in the saliva. According to Charnetsky and Brennan’s research, people who have sex 1-2 times a week notice a nearly 30% jump in the amount of antibodies available – a sign of increased immune protection. Similar increases in immunoglobulin concentrations were not reported in people having sex with a lower or higher frequency. The change in immune strength is due to the fact that sexually active people are exposed to a greater number of infectious agents and immunological irritants. Their immune system adapts to the increased danger by increasing the number of protective antibodies. They increase in number not only in saliva and mucous tissues, but throughout the body. In addition, they are effective not only against sexually transmitted pathogens, but also against common disease-causing microorganisms such as influenza viruses and colds. NEWS_MORE_BOX In addition – after reaching orgasm, the release of hormones such as oxytocin, prolactin and estrogen improve the duration and quality of sleep. Healthy sleep ensures a decrease in the stress hormone cortisol, the presence of which leads to a decrease in the strength of the immune system through its ability to suppress the production of interleukin-12, alpha- and gamma-interferon and tumor necrosis factor-alpha – important components for the immune system, without which the effective protection of the body falls sharply. A faster lowering of the body’s cortisol means a further increase in immune protection. Despite the well-studied benefits of regular sex for the immune system, it is important to practice safe sex and know practices to avoid unwanted pregnancy, as well as the risk factors of contracting sexually transmitted infections.