? Do they really offer a performance edge, or is the polished marketing little more than high-protein hype?
Wait, what are peptides?
Peptides are short chains of amino acids, the fundamental building blocks of protein in our bodies. They are essentially “pre-digested” protein fragments.
Unlike whey protein, which is readily digested and absorbed by the body, collagen protein can’t be easily digested due to its very large and complex structure (much larger than whey protein).
However, as peptides are much smaller molecules and are more easily absorbed, you should only look for collagen supplements that are sold in peptide form.
The production of peptide supplements typically involves a process called enzymatic hydrolysis. During this process, collagen protein obtained from cow hide or fish scales, for example, is treated with specific enzymes called proteases.
These proteases act like biological scissors. They essentially snip the long protein chains into tiny fragments, which are the peptides.
Because of this processing, peptides have a much lower molecular weight (smaller size) than their parent proteins. This allows them to be more easily absorbed in the small intestine, transported through the bloodstream and used wherever there is a need, such as in muscles, tendons and joints.
So, do they work?
Research into peptides for workouts provides a mixed but interesting picture.
When it comes to pure muscle growth (known as hypertrophy), peptides derived from whey protein are generally considered superior to those derived from collagen.
However, in a study published in 2022, the authors concluded that after a ten-week resistance training program in young adults who ingested either whey protein or collagen peptides enriched with an amino acid known as leucine, whey was better in terms of increasing muscle size. But both proteins resulted in similar gains in strength and power.
Collagen peptides also show significant promise in athletic performance improvement when combined with vitamin C. This is because collagen peptides require vitamin C to help them better incorporate into their necessary structure, resulting in stronger collagen formation in tissues.
A 2021 trial involving male athletes found that vitamin C-enriched collagen peptides improved explosive power during squats and jumps, likely by increasing the stiffness and efficiency of the “springs” in our tendons.
Unlike whey peptides, collagen peptides are rich in glycine and proline. These amino acids specifically support tendons, ligaments and cartilage.
Research suggests taking 15 grams of collagen peptides in combination with vitamin C roughly 60 minutes before a workout may stimulate the production of new collagen in these tissues. This potentially protects against injury.
Studies have also demonstrated that ingesting 20g of collagen peptides daily can help reduce muscle soreness . It can also accelerate the recovery of muscle function after strenuous exercise .
Many of these studies, however, are small in scale. Small-scale clinical trials are limiting because the relatively low number of participants reduces the ability to apply the results to the broader population.
These studies also vary in the type of peptide provided, resulting in mixed findings.
This is important because the actual peptide sequences (the order of the specific amino acids found in the peptides) and size of the peptides can vary significantly between brands.
This means the benefits of one product may not apply to another.
It’s also worth remembering that once the peptides are absorbed into our blood stream, our body uses them wherever they are most needed – not necessarily in the skin, joints or other specific areas people may be hoping to target.
What are the risks?
For most of the general population, peptides are considered safe and well-tolerated .
Because they are often derived from food sources, the body processes them much like any other dietary protein.
The primary concern relates to contamination from the source.
For example, in the case of marine-sourced collagen peptides, there might be potentially harmful chemicals present in the fish species from which the collagen has been extracted.
This is not exclusive to collagen. It also applies to other marine-sourced supplements, such as omega 3 fish oils.
Research has also found some marine-sourced collagen products may contain low levels of mercury and arsenic. However, these were within the European Union’s regulatory limits, and average daily doses were consistently below what is defined as tolerable daily intakes.
Leonidas Karagounis is professor research translation & enterprise, Australian Catholic University.