With the recent release of the Australian Crime Commissions (ACC) report into “Organised Crime and Drugs in Sport”, the general public have been bombarded with a range of stories about the use of ‘peptides’ by various athletes across different sporting codes. The problem is that the average individual doesn’t really know what a ‘peptide’ is.
Looking it up on wikipeadia doesn’t provide much help either with their definition reading:
“Peptides are short chains of amino acid monomers linked by peptide bonds”
To understand what a peptide is, one needs to have a basic understanding of protein structure. Protein is made up of different amino acids, much like words are made up of different letters. The structure of a given protein is defined by its amino acid composition, just like words are defined by the letters that make them up. Similarly, peptides are defined by virtue of their constituent amino acids, and their specific sequence. However, the key difference between peptides and proteins is essentially one of size. Peptides are classified as containing 50 amino acids or less, whereas protein can contain anywhere from 50 to several thousand amino acids.
One of the peptides frequently cited in the ACC report is growth hormone releasing hexapeptide or GHRP-6. As alluded to in the name, this particular peptide is made up of six amino acids. However, this and other similar peptides cited in the report are designed to be administered intravenously. If ingested orally, they’re broken down by the human digestive system into their constituent amino acids; rendering the original peptide useless to the human body.
Intravenous vs Oral Peptides
However, in contrast to the multiple growth hormone releasing peptides cited in the ACC report, there are certain peptides that can be taken legally in oral form, which also offer performance support & enhancing effects . Such peptides are termed dipeptides and tripeptides. As mentioned in Appendix One of the ACC report, these peptides can be found in whey protein hydrolysate. Again, as their name suggests, dipeptides and tripeptides are made up of two and three amino acids respectively.
Digestion of Dipeptides and Tripeptides
What’s more interesting is the fact that dipeptides and tripeptides are the only type of ‘peptides’ not broken down by the digestive tract, but are in fact absorbed whole. In fact, the gut has a specific transporter for di- and tripeptides (called Pept-1) which facilitates their fast absorption. Of particular interest to athletes is the fact that certain dipeptides and tripeptides found in hydrolysed whey protein have recently been found to have a number of highly desirable benefits for recovery, endurance and performance.
Just in the past few years, scientists and researchers have discovered some of the specific di- and tripeptides in hydrolysed whey protein that mediate its positive effects on recovery and performance. There are a limited number of supplements that contain highly concentrated amounts of these specific peptides; however they tend to come with a hefty price tag due to the extra cost of extracting them from whey protein hydrolysate. The most cost-effective option is to use a good quality hydrolysed whey protein, which contains naturally occurring di- and tripeptides. The highest grades of whey protein hydrolysate contain between 40-50% di- and tripeptides. So if there is one upside to the current scandal concerning illegal drug use in Australian sport, it’s that competitive athletes and fitness enthusiasts might become more educated on the benefits of legal oral supplements containing peptides from hydrolysed whey protein.