Salmon collagen pill may soothe sore knees in active adults

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Adults aged 20 to 65 years. * Self-reported, reproducible knee discomfort associated with any knee-loading activities for at least 3 months prior to screening. * Discomfort must occur in at least one knee during a nominated aggravating activity at least twice per week and subside with rest. * VAS rating of 30 mm to 75 mm during the past week for the nominated activity. * No current diagnosis of structural joint disease (e.g., osteoarthritis). * Engages in physical activity involving knee-loading movements at least twice weekly for 20+ minutes. * BMI between 20.0 and 32.5 kg/m². * In good general health with no significant medical comorbidities. * Able and willing to provide informed consent. * Capable of completing study procedures remotely using mobile technology. Exclusion Criteria: * Persistent knee pain at rest or recent acute lower-limb trauma. * Diagnosed structural or inflammatory joint disorders. * Current or recent physiotherapy targeting knee pain (within 6 months). * Allergy to fish or any study product ingredients. * Scheduled lower-limb surgery during the study period. * Other musculoskeletal disorders affecting ambulation. * Recent joint injections (within 3 months). * Use of joint supplements in the past 3 months. * Use of analgesics ≥3 days/week in the past 3 months. * NSAIDs/acetaminophen use is permitted with restrictions: * Not within 24 hours of blood sampling or VAS assessments. * Must be documented. * Chronic use of medications that affect musculoskeletal symptoms (e.g., muscle relaxants, gabapentinoids) unless infrequent (≤2x/week) and not within 24 hours of assessments. * Regular use of PPIs (\>3x/week in past month). * Systemic corticosteroids, immunosuppressants, or opioids within 4 weeks. * Unstable weight or significant recent dietary changes. * Significant medical conditions (e.g., cancer, hepatic/renal impairment, CVD, thyroid disease, diabetes). * Neurological, cognitive, or psychiatric disorders affecting participation. * Use of tobacco/nicotine or other substances. * Diagnosed sleep disorders. * Strict vegan diet or sedentary lifestyle. * Inability to swallow capsules. * Pregnant, breastfeeding, or planning pregnancy. * Women of childbearing potential not using contraception. * Participation in another interventional clinical trial.