Iron Supplements & Multivitamins: Effects on Male Sexual Health

🔴 Iron

• Fatigue and low energy, which directly dampens libido
• Reduced testosterone synthesis: Testosterone acts as a hepcidin inhibitor, helping regulate iron absorption. Low testosterone (common with anemia) further impairs iron metabolism in a cycle — Harrison's Principles of Internal Medicine 22E
• Erythropoietin (EPO) therapy in iron-deficient men has been shown to improve sexual function, work capacity, and physical performance — Brenner and Rector's The Kidney

• Iron accumulates in the pituitary gland and testes, disrupting the hypothalamic-pituitary-gonadal (HPG) axis
• Results in hypogonadotropic hypogonadism: low LH, low FSH, low testosterone
• Clinical consequences: decreased libido, erectile dysfunction, infertility, testicular atrophy
• Men are more affected than women (higher dietary iron intake, no menstrual losses) — Harrison's Principles of Internal Medicine 22E

⚠️ Key takeaway on iron: Correction of iron deficiency improves sexual health; but excess iron supplementation without a documented deficiency can cause hypogonadism and sexual dysfunction.

💊 Multivitamins — Key Components Relevant to Male Sexual Health

Zinc

• Critical for testosterone synthesis and spermatogenesis
• Zinc deficiency leads to reduced testosterone, poor sperm motility, low sperm count, and impaired fertility
• Supplementation in zinc-deficient men restores testosterone levels and improves sperm parameters
• Recent reviews confirm zinc's central role in idiopathic male infertility (PMID: 40002352, 2025 review in Antioxidants)

Vitamin D

• Low vitamin D is associated with low testosterone — listed in Harrison's as a secondary cause of hypogonadism (alongside measurement of serum 25-OH Vitamin D)
• Supplementation in deficient men may modestly raise testosterone levels

Vitamin B12 & Folate

• Deficiencies impair DNA synthesis in rapidly dividing cells — sperm are particularly vulnerable
• Low B12/folate → poor sperm DNA integrity, reduced sperm count, impaired motility

Vitamin C & E (Antioxidants)

• Oxidative stress damages sperm cells (DNA fragmentation, lipid peroxidation of membranes)
• Antioxidant vitamins protect sperm from reactive oxygen species (ROS)
• Recent research (PMID: 40505349, 2025) shows micronutrient antioxidants can reverse drug-induced male infertility via the NRF2/HO-1 antioxidant pathway

Selenium

• Required for the enzyme glutathione peroxidase, which protects sperm from oxidative damage
• Deficiency → poor sperm motility (asthenozoospermia)

Summary Table

Practical Guidance

• Iron supplements should only be taken if there is a confirmed deficiency (serum ferritin, CBC). Routine supplementation without deficiency risks iron overload and can cause sexual dysfunction.
• Multivitamins with zinc, vitamin D, antioxidants (C, E, selenium), and B vitamins provide a beneficial foundation for male sexual health and fertility.
• If you are experiencing sexual dysfunction, a blood panel checking testosterone, ferritin, vitamin D, zinc, and B12 is a good starting point before starting any supplementation.