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What Syntrax Tetrabol really contained

Around 2003 Tetrabol, the designer supplement produced by the American company Syntrax, was doing pretty well. Bodybuilders who took the steroid – which was disguised as a supplement – reported a weight gain of several kilograms and a slight decrease in fat mass. Almost a decade later Anne Bauer and Felicitas Rataj of the German Institute of Doping Analysis and Sports Biochemistry looked into exactly what Tetrabol contained. They discovered that the ingredients were different from the manufacturer's claims...

According to the manufacturer, the active ingredient in Tetrabol was the THP-ether of androst-4-ene-3,17-diol, a testosterone analogue which can be up to 60 percent as effective as testosterone. Androst-4-Ene-3,17-Diol was sold in the US as a pro-hormone until George Bush banned most pro-hormones in 2004.

Like testosterone, androst-4-ene-3,17-diol is not very suitable for oral use. Syntrax solved this problem by attaching a THP-ether to androst-4-ene-3, 17-diol. Animal studies done in the sixties showed that this improves the oral availability of steroid hormones. We don't actually believe this trick works in humans. The human stomach is so acid that THP-ether groups are soon separated from the steroid.

The formula of the substance that Syntrax said was in Tetrabol is shown below.

What Syntrax Tetrabol really contained
What Syntrax Tetrabol really contained

The big problem with labels in the land of supplements is that they are not always correct – and this was the case for Tetrabol too. Tetrabol actually contained a mixture of two compounds (1:1) shown above.

Chemists refer to both these compounds as 17-hydroxyandrosta-3,5-diene-17-THP. The difference between the two compounds is the way in which the ether is attached to the steroid.

Both compounds can attach themselves to the androgen receptor and may have a muscle strengthening effect, the researchers discovered from an in-vitro study they did. For this they used genetically modified yeast cells with an androgen receptor.

When the researchers studied what happens when humans take 17-hydroxyandrosta-3,5-diene-17-TH, they discovered five metabolites in their test subjects' urine. One of these you may be familiar with: 4-hydroxy-androstenedione, which is marketed as the anti-oestrogen Formestane, the structural formula of which is shown above.

Three of the metabolites had an androgenic effect, the researchers discovered. The strongest effect came from 4-OH-androst-4-ene-3,17-dione.

What Syntrax Tetrabol really contained

An analogue of 17-hydroxyandrosta-3,5-diene is still on the market. Physique Enhancing Science's Erase and Erase Pro contain androsta-3,5-diene-7,17-dione.

Arch Toxicol. 2012 Jul 19. [Epub ahead of print].

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