Zinc and Testosterone

Summary: Zinc is one of my ‘must-have’ ingredients in any testosterone booster – it is very effective at boosting the levels of free testosterone in the body. Zinc comes in the form of either a straight zinc supplement or can often come in the form of oyster extract. Either of these is fine and will do the job nicely.

How Much Zinc Should I take to Increase Testosterone?

A note of caution before consumption of zinc supplements. Care has to be taken to avoid toxicity due to very high dosage. A dose of higher than 40mg per day for a healthy male may cause Zinc toxicity that manifests as nausea and headaches. We recommend a dose of 30mg per day for it to be safe but still effective.


Oyster extract is a natural cocktail of several trace elements with Zinc being the major one. A good oyster extract contains 3mg of Zinc per gram of powder; this concentration is the highest among all bio-available sources. The human body requires Zinc for a number of important physiological processes like the synthesis of important proteins and enzymes, reproductive functions, immunity and general vitality.

Medically it has been established that Zinc deficiency leads to lower muscle gain, low strength, reduced sex drive and weight gain. This is primarily because a Zinc deficiency leads to reduced levels of testosterone and all the important downstream effects of testosterone are compromised.

Oyster extract is a very popular supplement among men who are looking to increase their testosterone levels because it contains the highest concentration of bioavailable Zinc in addition to other important trace elements. Although there are very few reports with clinical studies on Oyster extract, the studies on the effect of Zinc (the main constituent of the Oyster extract) strongly suggest a positive regulatory effect on the synthesis and production of testosterone in the body.

We have compiled information on the effect of Zinc supplements/ Oyster extract on improving the testosterone content in human and animal systems.

Zinc supplements improve testosterone and muscle strength

Study: Authors studied the effect of Zinc and magnesium supplements on muscle strength in 57 football players in an eight week study. Out of the total 57 players, 37 subjects completed the trial. The effect of the supplement was evaluated by measuring free testosterone levels and muscle strength through torque.

Result: The levels of free testosterone and muscle strength improved significantly in the subjects on supplements as compared to the group on placebo.

Conclusion: Zinc and Magnesium supplements improve the levels of testosterone and enhance the muscle strength in trained athletes.

Source: http://www.asep.org/asep/asep/BrillaV2.PDF

Zinc supplementation may help combat cancer

Study: Seventeen patients with a history of diabetes were given 30mg Zinc per day for eight weeks. The levels of a specific cancer marker (TNF alpha- a key defense marker against cancer) were assessed in the plasma as well within the cells producing this protein.

Result: The levels of cancer defense protein in the cells were higher in patients on Zinc supplements.

Conclusion: Zinc supplements like Oyster extract may help in fighting cancer.

Source: http://www.ncbi.nlm.nih.gov/pubmed/24403477

Oyster extract prevents reproductive defects in mice

Study: Mice were fed on Zinc deficient diet for 12 weeks to induce zinc deficiency and the effects were observed as reduced sperm count and reduced testis weight in male mice. The pregnant female mice had a higher incidence of fetal death, reduced birth weight and unsuccessful pregnancies.

Result: Oyster extract supplementation led to improved sperm motility and other reproductive functions.

Conclusion: Oyster extract prevents and reduces the reproductive system defects in male mice.

Source : http://www.ncbi.nlm.nih.gov/pubmed/15041778

Zinc affects testosterone levels and testicular function in rats

Study: Authors conducted a ten week study on albino rats by inducing zinc deficiency followed by supplementation with zinc extract. The effects were evaluated by assessing the levels of key reproductive hormones like follicle stimulating hormones, testosterone, luteinizing hormones and prolactin in the serum.

Result: Zinc deficiency led to low Zinc serum levels in rats. The levels of testosterone and prolactin were reduced in the zinc deficient rats.

Conclusion: Zinc is an important element directly impacting the levels of hormones like testosterone that ultimately have a bearing on the overall reproductive function.

Source: http://onlinelibrary.wiley.com/doi/10.1002/food.19890331007/abstract

Zinc deficiency reduces bio-conversion of testosterone to dihydro-testosterone in rat liver

Study: Authors in this study induced zinc deficiency in rats  and the levels of hormones were evaluated in the serum. In addition to assessing hormone levels, the authors studied hormone-receptors in important organs like the liver.

Result: The levels of free testosterone, luteinizing hormone were significantly reduced in zinc-deficient rats.

Conclusion: Zinc is essential for the production of testosterone and other reproductive hormones.

Source : http://jn.nutrition.org/content/126/4/842.full.pdf

Zinc supplements enhance testosterone levels after exercise

Study: Shafiei and co-workers investigated the effects of Zinc  and selenium single supplements on testosterone levels after a physical workout (cycling). 32 male road cyclists were given Zinc supplements (30mg per day) for four weeks. The serum testosterone levels were quantified after exercise and resting.

Result: The serum testosterone levels were higher in the group on Zinc supplements with simultaneous exercising.

Conclusion: Zinc supplements enhance testosterone levels after rigorous physical activity.

Source: http://www.ncbi.nlm.nih.gov/pubmed/21744023

Zinc supplements help in increasing testosterone levels in renal dysfunction patients

Study: 100 males with end-stage renal disease and on dialysis were given zinc supplements (as Zinc sulfate 250mg/day) for 6 weeks. At the end of the treatment, period serum testosterone, follicle stimulating hormone, luteinizing hormone, prolactin and serum zinc levels were estimated.

Result: Serum testosterone, luteinizing hormone and Zinc levels increased in the patients, but there was no effect on the levels of follicle stimulating hormone and prolactin.

Conclusion: Zinc did not affect the renal patients with sexual dysfunction, however, the levels of reproductive hormones like testosterone increased after 6 weeks of therapy.

Source: http://informahealthcare.com/doi/abs/10.3109/08860221003706958?journalCode=rnf

Zinc supplements help maintain testosterone levels after exhaustion exercise

Study: This study was taken up on ten professional male wrestlers for four weeks with zinc supplements ( 3mg/kg body weight/day) along with their normal diet. The hormone levels were quantified at the end of 4 weeks with resting and after exercise.

Result: The testosterone levels increased significantly after exhaustive exercise among the wrestlers on the supplements.

Conclusion: Zinc therapy can enhance physical performance.

Source: http://www.ncbi.nlm.nih.gov/pubmed/16648789

Excessive and prolonged Zinc intake linked to prostate cancer

Study: A mega-study was conducted on more than 46500 men in the United States with follow up for as long as 14 years to study the possible role of excessive Zinc intake in developing prostate cancer. Men consuming Zinc supplements at various concentration levels were included in the survey.

Result: Men who consumed more than 100mg of Zinc supplement per day for 10 years were at higher risk of developing prostate cancer. As compared to non-users, men who consumed 100mg of Zinc per day for long durations were also at a higher risk.

Conclusion: Excessive and prolonged consumption of Zinc supplements (more particularly) single supplements presents a risk of developing prostate cancer.

Source: http://www.ncbi.nlm.nih.gov/pubmed/12837837

These studies elaborate on the critical role of Zinc in the development and optimal functioning of the reproductive system. The specific functional role of this important trace element has been studied and described by inducing deficiency. A dosage of 30mg per day for 1-1.5 weeks has shown positive effects in humans. The effect of oyster extract is possibly due to high Zinc concentration in addition to other important trace minerals like magnesium.

There are a number of small unpublished studies on humans with the effects of Oyster extract/ Zinc supplements. All the studies unanimously claim a positive influence of Oyster extract/ Zinc supplement on the levels of testosterone. These supplements support general wellness in addition to improving the blood testosterone levels. However, Oyster extract must be carefully chosen as there are plenty of supplements in the market with low levels of Zinc and such supplements are generally less effective.

These supplements are essential for people who are undergoing muscle training, individuals with nutritional deficiencies like elderly and under certain disease conditions. Oyster extract is a natural product with a rainbow of other critical trace elements that help in the general improvement of immunity against diseases, general vitality, and strength. Though there is a lack of clinical studies on Oyster extract in the scientific domain, the effect of Zinc is well established and we expect a high consonance in the physiological effect of the two supplements.


Oyster extract and Zinc are highly potent supplements in improving testosterone levels, general vitality, muscle strength, testicular function and other reproductive hormones. The presence of other elements and cofactors helps in increasing the bioavailability of Zinc to the body.