EstroBlok is an estrogen blocker and testosterone booster by BPM Labs.
BPM Labs is the same great Australian/American supplement company that make Annihilate and The One.
As men age testosterone decreases but production of the muscle inhibiting oestrogen continues at the same level. EstroBlok works to maintain a healthy balance of oestrogen so that the muscle growth hormone, testosterone, can do its thing: building strong healthy muscle faster than ever.
6-bromoandrostenedione works by binding to ‘aromatase enzymes’ and blocking their function of converting testosterone to oestrogen (1).
Studies in humans are limited, and a safe and effective dose has not yet been established.
Chrysin is a bioflavinoid compound found in bee pollen.
Although it has been shown to increase testosterone in-vitro (not in the body), it is extremely poorly absorbed when taken orally.
One study using a 55mg dose of Chrysin over 21 days showed no influence on the testosterone of healthy males (2).
Indole-3-carbinol is naturally produced during the breakdown of a compound found in cruciferous vegetables, such as broccoli and cabbage.
Although studies are very limited in humans, it has been found to decrease oestrogen levels (3). The effective dose is unknown.
Eurycoma Longifolia is an Asian flowering plant, whose roots are widely known to have aphrodisiac effects.
Eurycoma Longifolia has shown anti-oestrogenic effects when injected in animals, but no human studies were found on this.
Standard dosage is 200-300mg of a 100:1 extract.
Muira Puama is another flowering plant known as an aphrodisiac, this one being native to the Amazon rainforest.
Its purpose in EstroBlok is to boost testosterone and mood (6), however neither benefit has been confirmed by human studies.
According to examine.com, the plant may have cognitive benefits, for which an effective dose is 1000mg. The estimated effective dose for mood improvement is 250mg.
Quercetin is a flavonoid found in onions, apples, broccoli, and other foods. It has been shown in in-vitro to decrease the enzyme conversion of testosterone into testosterone glucuronide (7), which is a form excreted by the body. More study must be done in human subjects.
Although not the benefit of focus, Quercetin may also increase endurance. This is possible due to its ability to boost the number of mitochondria (powerhouses) in muscle cells (8).
BPM Labs claims that Coumesterol works by mimicking oestrogen and blocking the body’s use of actual oestrogen.
Studies have shown this could be the case (9), but more research needs to be performed on human subjects. The effective dose is unknown.
6,7-Dihyrdrobergamottin and Narignin (Spelt Naringen on the Label)
6,7-Dihyrdrobergamottin is a natural compound found in grapefruit juice.
This compound stops the regulation of the metabolism of medications and supplements (10). This allows more of the other ingredients to be absorbed than the body would usually permit.
Narignin is a flavonoid compound that has essentially the same effect.
Who Takes It?
EstroBlok would be of most benefit to older males, or those with low testosterone levels.
How To Take
Consume one tablet three times daily, with food.
Eurycoma Longifolia and Muira Puama are both known aphrodisiacs and may increase libido. Any or all of the other oestrogen-blocking ingredients may also increase sex drive.
I3C.org warns that human trials of Indole-3-Carbinol have shown “side effects including skin rashes, intestinal pain, nausea, balance problems, tremor or an increase in liver enzymes”. These are more likely to be observed with higher doses.
Both 6,7-Dihyrdrobergamottin and Narignin can interact adversely with a variety of medications. Do not mix with other medications, especially those that advise against grapefruit juice.
Multiple ingredients are very under-studied, and may have unknown side-effects. If any unwanted symptoms persist, speak to a doctor and stop taking EstroBlok.
BPM Labs describe themselves as “a science and evidence based laboratory that specializes in fitness and health supplements that can take your workout to the next level”.
EstroBlok is almost there, and uses a variety of potentially effective ingredients that may be useful in blocking oestrogen and increasing testosterone.
In honesty, there are several other T-booster ingredients not in this formula that are backed by better evidence.