Zinc is an essential co-factor in testosterone biosynthesis. How zinc deficiency suppresses testosterone, the clinical evidence and which supplements contain the correct dose.
Zinc is an essential co-factor in testosterone biosynthesis and LH (luteinising hormone) release — the pituitary signal that triggers testicular testosterone production. Published research confirms zinc deficiency significantly suppresses testosterone. Most Western men are zinc sub-optimal. ZMA supplementation in deficient men significantly increases testosterone.
Zinc is required as a co-factor at multiple points in the testosterone biosynthesis pathway. Most critically, zinc is required for the activity of 5α-reductase (involved in DHT production) and for the proper function of the hypothalamic-pituitary axis that controls LH (luteinising hormone) release — the signal that triggers testicular testosterone production.
A landmark study in Nutrition (Prasad et al., 1996) demonstrated that zinc restriction in healthy young men produced a 73% reduction in serum testosterone over 20 weeks. Zinc supplementation in zinc-deficient elderly men restored testosterone levels significantly.
Western diets are commonly zinc sub-optimal. Risk factors include: high alcohol consumption, plant-based diets (phytates inhibit zinc absorption), regular intense exercise (sweating depletes zinc) and processed food-heavy diets. Blood zinc testing is available via most GPs.