Collagen: food exposure and functional outcomes
In this investigation
The bottle and the outcome are separate questions
I asked about bottled broth because I prefer drinking it to taking collagen powder. The main collagen investigation explains the earlier experiments and my shoulder context. These additional readings ask what was actually consumed, what changed, and whether that change establishes a useful benefit.
What one unusually rich broth delivered
A 2019 feeding experiment recruited 15 healthy active men, comparing six protein sources in randomized order after fasting. Each drink was consumed within five minutes. A deliberately selected rich café broth was assayed after feeding. In 300 mL, it supplied 11.76 g glycine and 6.42 g proline, versus 4.90 g and 2.72 g in the 20 g collagen-peptide powder serving. Those amino acids do not establish a measured collagen dose in the broth. Alcock and colleagues, 2019
Its blood amino-acid response was more prolonged; protein doses were unequal, limiting direct comparison. The experiment measured neither tendon healing nor symptom relief. Sports-team funding supported it; the authors reported no commercial conflicts. A concentrated café preparation cannot supply the missing composition of my eventual supermarket bottle.
A positive tendon measurement without an injury outcome
Of 18 professional women’s soccer players recruited, 15 were randomized and 11 completed ten weeks. They received 30 g liquid collagen or energy-matched carbohydrate before three weekly training sessions, both with 500 mg vitamin C. Stiffness increased 15.4% versus 4.6%, with a significant treatment-by-time comparison and nominal tests across several outcomes. Tendon area, muscle thickness and strength showed no added benefit. No injury benefit was demonstrated. Funding and conflicts were declared absent; the lead researcher was unblinded. This mechanical outcome does not establish shoulder healing. Lee and colleagues, online 2024; issue 2025
The registry was submitted in 2024 after 2021 collection and describes a broader project, not prospectively specified priority for this small completer analysis. Liquid collagen is not broth.
A newer clinical test did not find added benefit
A January 2026 conference abstract reports 36 male elite athletes with chronic Achilles, patellar or plantar-fascia tendinopathy randomized to 10 g daily hydrolyzed collagen or maltodextrin, alongside twelve weeks of heavy slow resistance training. Both groups improved, but primary sport pain and secondary symptoms, function and imaging showed no significant between-group benefit; symptom follow-up extended to 38 weeks. Thomsen and colleagues, 2026
This is a relevant clinical null, with a substantial limitation: the inspected report is an abstract. It supplies no complete participant flow, treatment-effect intervals or adverse-event analysis. It does not prove that every collagen preparation is ineffective, or that my reported shoulder has the same condition.
Improvement within one group can mislead
A separate 2026 male-soccer study tested 5 g collagen peptides daily for eight weeks against maltodextrin. Its flowchart shows 16 randomized and 13 analyzed, although the abstract presents 13 participants. The conclusion emphasizes lower pain and perceived exertion with collagen, but the actual treatment-by-time tests for these scores were P=.874 and P=.947. Both groups’ perceived exertion fell. Sprint, jump and strength results did not establish added benefit. Akgün and colleagues, 2026
A significant change inside the collagen group is not a demonstrated advantage over placebo. The paper also contains inconsistent descriptions of participant flow and pain results. A supplement manufacturer supplied the products. It reports no external funding or conflicts, while the official registry extract confirms retrospective registration and lists numerous primary outcomes. These limits make the positive headline an unreliable basis for a purchase.
What changes for my shopping
Broth stays optional. I can log its verified package and amount, leaving unmeasured collagen and glycine unknown. These studies establish neither a personal dose nor a defined shoulder treatment.