Research published in Biological Trace Element Research (1990; 24:83–89) explored how zinc supplementation affects cortisol production. Earlier studies had suggested that both high and low zinc levels might influence adrenal secretion, but data were inconsistent. This study examined the immediate effect of oral zinc intake on cortisol levels in healthy adults.
The subjects were 27 healthy men and women, ages 20–27, randomly assigned to receive either zinc or a placebo. The zinc group received 25 mg, 37.5 mg, or 50 mg of zinc. Fasting cortisol levels were taken at 7:00 AM, the supplement was administered at 8:00 AM, and blood samples were collected over the following four hours.
The findings showed that zinc caused an acute decrease in cortisol secretion during the testing window. The placebo group showed no such change.
While this was a small, early study, it suggests that zinc may play a short-term modulatory role in cortisol response. Later research has explored zinc’s involvement in stress physiology, immune function, and the HPA axis, but more human trials are needed to clarify long-term or clinical implications.
