Thanks for posting here, Brief answer : sperm loss doesn t cause iron deficiency Detailed answer: What you describe is probably a state of iron deficiency with or without anemia. Iron balance in the body is regulated by regulation of iron absorption. However if your diet low in iron you would develop iron deficiency status. Also if you take food which interfere with iron absorption from the intestine like excessive caffeine, tea can also cause iron deficiency status. According to your details as iron loss is very unlikely especially as you are a male (in female menstrual loss can results in iron deficiency commonly). However in a male iron deficiency status should be investigated thoroughly. Parasitic infestation especially hook worm can cause unnoticed bleeding and cause iron deficiency. Gastritis and asymptomatic gastric ulcers can also cause iron deficiency. Don t worry, Sweating and sperm loss won t cause iron deficiency status practically. Investigation including serum Ferritin levels and blood picture, ESR , stool for occult blood should be done as baseline. Hope the answer is helpful. Thank you.