Blocking Estrogen


Estrogens – group of female sexual hormones (like estradiol, estrone, estriol). They are present in small quantities also in male body.

Estrogen effects on males – gynecomastia (enlargement of breast), fat and water accumulation, low libido

Causes of high estrogen in men – 1. Testosterone is turned into estrogens by enzyme aromatase in a process called aromatisation 2. Low testosterone levels signal to the body to replenish steroid hormone levels, if testosterone production is inhibited, estrogens take its place.

GSE acts as aromatase inhibitor – scientific studies show that the Grapeseed Extract (GSE) acts as a potent inhibitor of aromatase enzyme, thus preventing conversion of testosterone to estrogen, mostly by active substances procyanidin and proanthocyanidin (see RESEARCH). In fact, GSE is possibly stronger aromatase inhibitor than common medical drugs Tamoxifen and Anastrozole.

Tetrasterone™ contains proper dose of GSE – in addition to piperine, serving as a hugely efficient bioavailability-enhancing compound. Small doses of GSE are useless – Tetrasterone™ contains 1g in every capsule, as tested on human subjects (when using 2 caps/day).

Eurycomanone is another aromatase inhibitor – Eurycomanone, the main active substance in Eurycoma longifolia, has been shown to block aromatase enzyme (see study). The recommended daily dose of Tetrasterone™ contains higher amounts of eurycomanone than those used in scientific studies.

Blocking estrogen results in higher testosterone – when estrogens cannot be synthesised, the negative-feedback reaction signals lack of steroids. Thus, other steroids are produced in higher amounts – in our case, testosterone. In fact, this is how bodybuilders re-start their natural testosterone production by anti-estrogens after anabolic steroid cycles.