When you orgasm, the brain releases a cocktail of neurochemicals that make you tired. "During sex, the brain releases oxytocin which heightens arousal and excitement," Laino told INSIDER. "But when it wears off, it can leave people feeling really tired."

Why do guys feel tired after ejaculation?

According to health experts, as soon as a man reaches orgasm, his body chemistry changes. This happens when the biochemical prolactin is released, it makes him tired and he tends to sleep after an intimate session.

Do you have less energy after ejaculation?

', Mark Leyner and Billy Goldberg, explain the phenomenon by saying, “It is thought that exertion during sex and after climax depletes the muscles of energy-producing glycogen. This leaves men feeling sleepy. Since men have more muscle mass than women, men become more tired after sex.”