Sunday 10 February 2013

Australians doping with designer peptides: do they work as sports drugs?

The news that doping with custom peptides (such as CJC-1295, Sermorelin and Tesamorelin) is widespread in Australian sport has been all over the web recently. So I thought I should add my opinion to a somewhat confused story (at least in terms of how the biochemistry and sports performance is being reported). The first confusion is the use of the word “peptide” as if it is some evil drug. Peptides are just a string of amino acids that make up a protein. If the number of amino acids is small the resultant molecule is called a peptide. If there are lots of amino acids strung together it is called a protein. The distinction between a peptide and a protein is therefore essentially arbitrary. So insulin, human growth hormone and erythropoietin are all peptide hormones. But they could just as easily be called protein hormones. This biochemical distinction is being lost in the current discussions about doping in Australian sport, where peptides are just bad molecules you get from criminal gangs.

So what are these artificial designer peptides? They are drugs that are being used to enhance the release of the body’s own peptide hormones. The synthetic peptides work by mimicking other peptides in the body such as GHRH (growth hormone releasing hormone). So Sermorelin (a synthetic peptide) mimics GHRH (a peptide produced in the body) in activating the release of human growth hormone (also a peptide) from the pituitary gland. This is then supposed to increase muscle mass and power. Confused? Well read my book and there will be a test later (only kidding!).

Worryingly many of the drugs are still in clinical trials, or have been used in such trials and found wanting, and so are not licensed for use in humans. So they have to be obtained by links with organised crime. I can’t help feeling that the most interesting aspects of this story are exactly that: doping is widespread in many sports and very closely linked to criminal elements. As we all knew pro-cycling is not an isolated case

Although we have not got all the details yet, what I am not overly concerned that the drugs themselves will have biased the results of sporting events (though I AM concerned about the health of athletes concerned). Why am I not concerned about the cheating? Well many of the peptides are touted to be an undetectable way of raising your human growth hormone (HGH) levels. This is supposed to increase muscle mass and strength. Yet the experimental evidence for a power increase with HGH administration itself is very weak (M.J. Rennie (2003) Claims for the anabolic effects of growth hormone: a case of the emperor's new clothes?, Br. J. Sports Med. 37 100-105). It is therefore unclear that doping with peptides designed to indirectly increase HGH levels will be any more effective.

Of course these statements must be couched with the usual caveats that most studies are not done on elite athletes and, for ethical reasons, err on the low side in dosage. But even a quick trawl through the bodybuilder web sites reveals some dopers who think the claimed benefits of “peptides” are all just a placebo effect. If even bodybuilders are sceptical your product works, you really should doubt its efficacy.

It should also be noted that these drugs were designed for specific clinical problems such as to increase growth in growth hormone deficient patients or to increase fat breakdown in HIV-AIDS patients, in particular to treat a symptom called HIV-associated lipodystrophy (excess abdominal fat). Although they aim to increase lean body mass, this is by reducing fat. They have not been designed to increase muscle mass and power per se. So the clinical data do not directly support their use in athletes. Like HGH the use of these synthetic peptide hormone are touted by what I term “lifestyle clinicians” in the USA to solve all sorts of issues relating to ageing and/or weight problems. This is “off label” prescription i.e. the drugs are not officially approved for this use (which usually means, of course, that there is no supporting data).

So what is the problem if the drugs probably aren’t affecting performance too much? Well some of the drugs are not licensed for use as they have undesirable side effects. Or they may be licensed in sick patients where there have benefits that outweigh the side effects. For example in 2010, the US Food and Drug Administration approved Tesamorelin for treating Lipodystrophy in HIV patients ( But they noted that: “the long-term cardiovascular benefit and safety of tesamorelin have not been studied”, “Tesamorelin increases serum levels of insulin-like growth factor 1 (IGF-1), which has an unknown effect on the development or progression of malignancies” (i.e. cancerous tumors), and “Tesamorelin therapy may also result in glucose intolerance and an increased risk for diabetes mellitus”. It seems from the reports that some of the Australian athletes may have not been told what drugs they were being given. In this case it is not only the supplying gangs that are criminals, but the people who administered the drug as well …..


  1. Are they drugs or are they 'supplements'?
    The strange pursuit of nutritional doping around the prohibited list prevails because of the arbitrary way WADA classifies what is prohibited and athletes (and their entourage) seek to exploit any potential advantage.

  2. You make a valid point. However, as I note in the book most "nutritional supplements" that claim drug-like activity are a big con. Indeed if they really did what they claim to be they could not be sold over thew counter (the claims are frequently vague for just these legal reasons).

    Anyway the peptides discussed in this article (e.g. tesmorelin) are all synthetic drugs that you cannot get in nature.

  3. Very nice post. Keep on sharing your views

  4. Thanks - I am tied up with student marking at present. I hope to re-emerge into the blogosphere soon!