Agar and undenatured type II collagen for easing knee and joint pain
Official title: Evaluation of the Effect of Agar and/or Collagen Based Compounds on Osteoarticular Pain. A Randomized, Parallel, Placebo Controlled, Triple Blind Clinical Trial (AGARTROSIS)
Run by Fundació Eurecat · NCT07318896 · Data updated 2026-11-12
This trial will try whether daily agar-agar, undenatured type II collagen, or their combination reduces knee pain in adults aged 40–70 with mild to moderate knee pain.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 40 Years to 70 Years |
| Sex | All |
| Enrollment | 80 (estimated) |
| Sponsor | Fundació Eurecat Academic / other |
| Locations | 1 site (Reus, Tarragona) |
| Status | Recruiting |
| Started | November 10, 2025 |
| Main results expected | February 2027 |
| Study ends | February 2027 |
| Registry record updated | January 6, 2026 |
| Trial ID | NCT07318896 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are adults 40–70 years old with mild to moderate knee pain (WOMAC pain score 6–10), BMI between 18.5 and under 30 kg/m2, not dependent on prescription pain medications, and able to read Spanish or Catalan.
✕Probably not a fit
People with BMI ≥30 or <18.5, a formal osteoarthritis diagnosis, recent corticosteroid treatment, dependence on prescription analgesics, allergies to agar or collagen, or current use of collagen-containing supplements are unlikely to benefit or be eligible.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This is a randomized, placebo-controlled, triple-blind, parallel-group nutritional intervention that randomly assigns participants to one of four arms (agar-agar, undenatured type II collagen, the combination, or placebo). A total of 80 men and women with mild to moderate knee pain will be enrolled and followed with patient-reported outcomes and objective function tests. The primary outcome is knee pain measured by the WOMAC pain subscale; secondary outcomes include stiffness, functional capacity (subjective and objective), range of motion, medication use, body composition, and blood markers of inflammation and collagen/bone metabolism. The trial is conducted at the Eurecat Nutrition and Health Unit in Reus, Tarragona, Spain, and excludes people taking certain medications or supplements that could affect results.
Why it matters
Potential benefit: If successful, these natural compounds could reduce knee pain and stiffness, improve function, and lower reliance on pain medications with fewer long-term side effects than regular anti-inflammatory drugs.
How similar studies have gone: Small clinical trials of undenatured type II collagen have shown modest benefits for joint pain and function, whereas agar-agar has limited clinical evidence and the combination approach is largely novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Men and women between 40 and 70 years of age. * Submit a score of 6 to 10 out of 20 on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) knee pain questionnaire. * Sign the informed consent form. * Know how to read, write, and speak Spanish and/or Catalan. Exclusion Criteria: * Present body mass index (BMI) values \<18.5 kg/m\^2 or ≥30 kg/m\^2. * Present intolerances or allergies related to Agar-Agar, or any of the components of the products being evaluated, such as collagen or maltodextrin. * Take or have taken medications that may affect the study results. This is especially true for those who have been treated with oral or intra-articular corticosteroids within the 4 and 12 weeks prior to screening, respectively, or medications for osteoarthritis at the time of screening. * Patients who depend on prescription medications for pain control. * Take multivitamin or mineral supplements, collagen derivatives, or supplements containing bioactive compounds that may exert an anti-inflammatory effect, such as turmeric, ginger, omega-3, or polyphenol supplements. (Individuals who consume multivitamin, mineral, or collagen-derived supplements or supplements will be eligible to participate in the study, provided they are willing to discontinue their intake for at least two weeks prior to the start of the study and throughout the entire study period). * Be an active smoker or have been one for less than 6 months. * Alcohol consumption: * Men: Consume 4 or more Standard Drink Units (SDU) daily or SDUs weekly. * Women: Consume 2 or more Standard Drink Units (SDU)\* daily or SDUs weekly. * Have a diagnosis of osteoarthritis, active rheumatoid arthritis, and any inflammatory arthritic condition such as secondary inflammatory arthritis, gout, pseudogout, knee infection, marked angular deformities, or significant injury to the target joint within the 6 months prior to the start of the trial; arthroplasty and joint surgery of the target knee within the 2 years prior to the start of the study. * Have any gastrointestinal disease that affects the absorption of the compound and/or the study results, such as celiac disease, Crohn's disease, active cancer of any organ of the digestive or renal system, or hepatitis. * Be ineligible to participate in the study, according to the pre-screening evaluator's criteria. * Have lost 3 kg or more in the last 3 months. * Be pregnant or intend to become pregnant. * Be breastfeeding. * Be unable to follow the study guidelines. * Be participating or have participated in a clinical trial involving drug intervention or nutritional intervention within the last 30 days prior to inclusion in the study.
Where it's running
-
Eurecat, Technological Center of Catalonia, Nutrition and Health Unit
Reus, Tarragona, Spain Recruiting
Study contacts
- Principal investigator: Antoni Caimari Palou, PhD — UTNS (Eurecat, Reus)
- Study coordinator: Antoni Caimari Palou, PhD
- Email: antoni.caimari@eurecat.org
- Phone: 0034 977 300 805
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.