Wednesday, 30 July 2014

GW501516: Update on endurobol and doping: some thoughts about dosing

In a previous blog [1], I noted that there was no evidence in animals that endurobol improved performance in animals. I must apologise as I missed a rather important paper from Ron Evans group in 2008 that showed just that. The performance effect was only seen if the mice were also doing exercise training [2].

What is interesting is the doses that were used in this study. The four-week program of exercise training was paired with 5 mg/kg/day of the drug. This is at the low range of the long-term (2 year) toxicity study done by Glaxo [3], which varied from 0 – 80 mg/kg/day. But some adverse effects were still seen at the 5mg/kg/day level.

Interestingly one anonymous commentator on my previous blog said that he/she knew people who have been using it at a dosage of 10 mg per day for fat loss purposes and 20 mg per day for a performance enhancing benefit. Indeed some companies are selling pills of 5 mg size [4]. However, these doses are far lower than are shown to work in the Evans paper (for an average 85 kg human, the “Evans” dose should be 425 mg/day  - or three full bottles every day of the pills that some manufacturers are selling.

The usual caveats apply. There are long-term toxicity effects of this compound and it is generally easier to show performance effects in laboratory rats and mice than highly fit trained athletes.

  1.  http://runswimthrowcheat.blogspot.co.uk/2014/02/gw501516-endurobol-and-doping-whats-all.htm
  2.  Narkar VA, Downes M, Yu RT et al (2008) AMPK and PPARdelta agonists are exercise mimetics. Cell 134:405-415.
  3.   Toxicological Sciences Volume 108, Number 1, March 2009 Abstracts # 895 and 896    
  4. http://www.sarms-supply.com/gw501516-c-95.html



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