Clinical evidence for low-molecular-weight collagen peptides in tendon and ligament tears: a systematic review with narrative synthesis.

BACKGROUND: Low-molecular-weight hydrolyzed collagen peptides are increasingly used as adjuncts in musculoskeletal medicine, but their clinical role in tendon and ligament injuries remains unclear. OBJECTIVE: To evaluate clinical evidence on oral or injectable hydrolyzed collagen peptides, or related low-molecular-weight peptide preparations, in tendon and ligament injuries and post-repair/reconstruction settings. METHODS: A systematic review with narrative synthesis was conducted using PubMed and a mirrored Scopus strategy through 17 March 2026. Eligible studies were human clinical studies assessing hydrolyzed collagen peptides or clearly related low-molecular-weight peptide formulations in tendon tears, ligament tears, or postoperative repair/reconstruction. Closely related disorders were included only as contextual evidence when direct injury-specific data were limited. RESULTS: Six studies met the eligibility criteria. Three provided direct evidence in tear or post-surgical populations: one pilot study of injectable low-molecular-weight peptides in partial supraspinatus tendon tears, one randomized trial after ACL reconstruction, and one randomized trial after rotator cuff repair. Three additional studies provided indirect evidence in Achilles tendinopathy, chronic ankle instability, and rotator cuff tendinopathy. Overall, collagen-based interventions were associated with improvements in pain, function, analgesic use, or imaging-related outcomes. However, most oral interventions were multicomponent, and only one direct tear study evaluated a clearly defined low-molecular-weight peptide formulation. CONCLUSIONS: Hydrolyzed collagen-derived peptides show a cautiously positive signal as adjuncts to rehabilitation or postoperative care. However, evidence in tendon and ligament tears remains sparse, heterogeneous, and low certainty. Further blinded, placebo-controlled trials using well-characterized formulations and clinically meaningful outcomes are needed.