Tier 2 — strong

Coingestion of Collagen With Whey Protein Prevents Postexercise Decline in Plasma Glycine Availability in Recreationally Active Men

Aussieker T, Janssen TAH, Hermans WJH, Holwerda AM, Senden JM, van Kranenburg JMX, Goessens JPB, Snijders T, van Loon LJC
International journal of sport nutrition and exercise metabolism 2024 34(4):189-198

Bibliography

PubMed
PMID 38604602
DOI
10.1123/ijsnem.2023-0264
Funding
Funding was not specified in the indexed abstract; the full funding disclosure has not been verified.
Competing interests
The accessible abstract does not establish the authors' competing interests; absence of a statement is not evidence of no conflicts.

Study snapshot

DesignRandomized controlled human intervention
ModelAdult humans
Sample14 recreationally active men
Intervention30 g total protein: whey with 0, 5, 10 or 15 g collagen after resistance exercise
Duration6 hours of postexercise sampling per condition
EndpointsPlasma glycine kinetics; Leucine and essential amino acid availability

What the study showed, in plain terms

Adding collagen to whey increased postexercise glycine availability, while greater collagen substitution reduced the essential-amino-acid response. This is an absorption study rather than proof of better muscle growth.

Key findings

  • Five grams of collagen with 25 g whey prevented the fall in glycine seen with whey alone.
  • Higher collagen amounts produced larger glycine exposure but lower leucine/essential amino acid availability.

What this study can and cannot tell us

Blood amino acid availability does not establish tissue adaptation, recovery or clinical benefit.

The study tested protein mixtures, not isolated glycine capsules.

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Editorial review

Reviewed by the Biohack Blueprint research team

Last verified

Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction