Collagen peptides complete protein
Pro Research Analysisby 
Searched over 200M research papers
Collagen Peptides as a Complete Protein: An Analysis
Collagen Peptides and Protein Quality
Collagen peptides have gained popularity for their potential health benefits, but there is ongoing debate about their classification as a complete protein. According to the Protein Digestibility-corrected Amino Acid Score (PDCAAS), collagen protein is considered incomplete because it lacks one indispensable amino acid, tryptophan, and has a low profile of other essential amino acids . Despite this, collagen peptides are rich in conditionally indispensable amino acids and bioactive peptides that can support various physiological functions, particularly in aging and exercise contexts .
Functional Benefits of Collagen Peptides
Muscle Recovery and Strength
Research indicates that collagen peptide supplementation, when combined with resistance training, can enhance muscle mass and strength. Studies have shown that collagen peptides can increase fat-free mass (FFM) and muscle strength in both elderly sarcopenic men and middle-aged untrained men 378. For instance, a 12-week resistance training program combined with collagen peptide supplementation resulted in significant improvements in body composition and muscle strength compared to a placebo 78. However, when collagen peptides were compared to whey protein, no significant differences were found in muscle recovery and performance during eccentric exercise training .
Collagen Peptides in Diet
Incorporation in Western Diets
Despite being an incomplete protein, collagen peptides can be incorporated into the diet without compromising the balance of indispensable amino acids. Iterative PDCAAS calculations suggest that up to 36% of dietary protein can be substituted with collagen peptides while still meeting essential amino acid requirements . This finding supports the feasibility of including functional amounts of collagen peptides (2.5 to 15 g per day) in the standard American diet .
Mechanisms and Molecular Insights
Protein Composition and Muscle Proteome
Collagen peptides primarily consist of non-essential amino acids, which play a role in muscle protein synthesis and recovery. A study on the skeletal muscle proteome revealed that collagen peptide supplementation led to the upregulation of proteins associated with contractile fibers, indicating enhanced muscle protein metabolism . This molecular insight underscores the potential of collagen peptides to support muscle health, particularly when combined with resistance training.
Conclusion
While collagen peptides are not classified as a complete protein due to their lack of tryptophan, they offer significant functional benefits, particularly in muscle recovery and strength enhancement. Their incorporation into the diet can be substantial without disrupting essential amino acid balance. Therefore, collagen peptides can be a valuable addition to dietary and exercise regimens, especially for aging populations and those engaged in resistance training.
Sources and full results
Most relevant research papers on this topic