OsteearthritisAGARTROSISNCT07318896
Effect of Agar/Collagen-based Compounds on Osteoarticular Pain: Randomized Triple-blind Clinical Trial
A study testing Agar-Agar, Agar-Agar and undenatured collagen type II and undenatured collagen type II in people with Osteearthritis and Joint Damage, run by Fundació Eurecat at 1 site in Spain.
Trial summary
Joints-comprising bone, cartilage, ligaments, and synovial fluid-enable stable daily movement but may deteriorate with age, excess body weight, overuse, injury, or disease. Such degeneration, common from age 40 onward, underlies joint disorders like osteoarthritis, particularly in the knees, hips, hands, and spine… Read more about this study
- Who is it for?
- Ages 40 to 70 years
- Conditions the study is for
- Osteearthritis, Joint Damage, Inflammation
- What is being tested?
- Agar-Agar, Agar-Agar and undenatured collagen type II and undenatured collagen type II
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 1 siteSpain
- Study dates
- 10 Nov 2025to Feb 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 40 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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).
Show all 18Show fewer
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Spain1 site, 1 recruiting
- Recruiting
Eurecat, Technological Center of Catalonia, Nutrition and Health Unit
Reus, Tarragona, 43204
Anna Crescenti Savall, PhD, +34 977 300 431 ext. 4832, anna.crescenti@eurecat.org
Maria Josefina Ruiz de Azua, PhD, +34 977 300 431 ext. 4835, josefina.ruizdeazua@eurecat.org
About this study
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)
Joints-comprising bone, cartilage, ligaments, and synovial fluid-enable stable daily movement but may deteriorate with age, excess body weight, overuse, injury, or disease. Such degeneration, common from age 40 onward, underlies joint disorders like osteoarthritis, particularly in the knees, hips, hands, and spine, and is a major cause of chronic pain and disability. While antiinflammatory analgesics remain the standard approach to symptom control, they neither cure disease nor regenerate cartilage and can produce significant long-term adverse effects (gastrointestinal, hepatic, renal, and cardiovascular). These limitations motivate interest in natural or complementary strategies with safer profiles.
Within this context, marine algae, especially agar derived from red seaweed, have attracted attention for potential intestinal, metabolic, and joint benefits, aided by their fiber content. Another promising option is undenatured type II collagen (UC-II), the principal structural component of articular cartilage, whose endogenous production declines with age; clinical studies indicate that a daily intake of 40 mg UC-II can improve mobility, reduce pain, and enhance quality of life in individuals with osteoarthritis or exercise-related joint discomfort. Based on these considerations, an agar-agar supplement has been developed to relieve knee joint symptoms.
Read the detailed description
The primary objective of this study was to evaluate the effect of agar-agar (A-A), the combination of A-A with undenatured type II collagen (A+UC-II), and undenatured type II collagen (UC-II) on knee joint pain, assessed by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), in subjects with mild to moderate joint pain without a diagnosis of osteoarthritis, compared with a control compound.
The secondary objectives were to evaluate the effects of A-A, A+UC-II, and UC-II consumption on:
- Knee joint stiffness and functional capacity (subjective assessment).
- Overall perception of knee health (subjective assessment).
- Pain, stiffness, and functional capacity of the hand (subjective assessment).
- Range of motion of the knee.
- Functional capacity of the knee (objective assessment).
- Functional capacity of the hand (objective assessment).
- Frequency of medication use for joint pain relief (anti-inflammatories, analgesics).
- Inflammatory blood markers.
- Blood markers of collagen and bone metabolism.
- Body composition.
The primary endpoint is patient-reported knee joint pain, assessed using the Pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire.
This is a randomized, placebo-controlled, triple-blind, parallel-group nutritional intervention with an allocation ratio of 1:1:1:1. A total of 80 participants (men and women) will be enrolled. Following a pre-screening visit to verify inclusion and exclusion criteria, eligible participants will be randomly assigned to one of four groups (n=20 per group) to consume, once daily for 12 weeks, one of the following products: agar-agar (A-A), A-A+UC-II (A+UC-II), UC-II alone, or placebo.
Each participant will complete three in-person visits and one interim telephone follow-up: a pre-screening visit (eligibility assessment), a baseline visit to initiate the intervention, a mid-study telephone follow-up, and an end-of-study visit. The total duration per participant will be 13 weeks.
The primary endpoint is patient-reported knee joint pain, assessed using the Pain subscale of the WOMAC questionnaire.
- Conditions
- Osteearthritis, Joint Damage, Inflammation, Cartilage Damage
- Being tested
- Agar-Agar, Agar-Agar and undenatured collagen type II, undenatured collagen type II, Placebo
- Keywords
- Agar-Agar, undenatured collagen type II, Joint pain, knee pain
- Medical subject headings
- Inflammation, Arthralgia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Agar-AgarDietary supplement
Also called (A-A)
2.4 g of agar-agar (Rhodophyceae group) presented in capsule form will be given.
Agar-Agar and undenatured collagen type IIDietary supplement
Also called (A+UC-II)
2.4 g of agar- agar + 40 mg of undenatured collagen type II, presented in capsule form will be given.
undenatured collagen type IIDietary supplement
Also called (UC-II)
40 mg of undenatured collagen type II + 2.4 g of maltodextrin will be given in capsule form
PlaceboDietary supplement
2.4 g Maltodextrin will be given in capsule form
| Study group | Role | What they receive |
|---|---|---|
| Agar-Agar (A-A) | Experimental | Participants assigned to this group will receive agar-agar (A-A) supplementation and will take it for 12 weeks. Receives: Dietary Supplement: Agar-Agar |
| Agar-Agar + undenatured collagen type II (A+UC-II) | Experimental | Participants assigned to this group will receive agar-agar and undenatured collagen type II (A+UC-II) supplementation and will take it for 12 weeks. Receives: Dietary Supplement: Agar-Agar and undenatured collagen type II |
| undenatured collagen type II (UC-II) | Active comparator | Participants assigned to this group will receive undenatured collagen type II (UC-II) supplementation and will take it for 12 weeks. Receives: Dietary Supplement: undenatured collagen type II |
| Placebo | Placebo comparator | Participants assigned to this group will receive the placebo and will take it for 12 weeks. Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in perception of knee joint pain.
This will be determined using the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire.
The questionnaire assesses clinically meaningful changes in symptoms and physical disability in individuals with osteoarthritis or those experiencing joint discomfort. It evaluates the perceived intensity of knee pain using the Likert scale (0: no pain; 1: mild pain; 2: moderate pain; 3: severe pain; 4: extreme pain).
Measured: Before (baseline), during (6 weeks) and after treatment period (12 weeks).
Secondary outcomes (42)
Body weight.
Body weight will be measured by Tanita TBF-300 (Body Composition Analyzer, Brooklyn NY, USA) as a descriptive variable.
Measured: at week 1.
Height.
Height will be measured by standardized method.
Measured: At week 1.
Body mass index (BMI) (kg/m^2).
BMI will be determined using the Tanita TBF-300 (Body Composition Analyzer, Brooklyn, NY, USA) as a descriptive variable.
Measured: At week1.
Age.
Age will be recorded in years.
Measured: At week 1.
Changes in systolic and diastolic blood pressure and resting heart rate.
It will be measured using an automatic sphygmomanometer.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in body weight.
Body weight will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Change in BMI.
Weight and height will be combined to report BMI in kg/m^2.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of body fat.
Body fat in kg will be measured with Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of body fat.
Body fat percentage will be measured with Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of muscle mass.
Muscle mass in kg will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of muscle mass.
Muscle mass percentage will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of bone mass.
Bone mass (kg) will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of total body water.
Total body water (Kg) will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Change in the amount of lean mass.
The total lean mass (Kg) will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in bone mineral content.
This will be measured, in Kg, by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in segmental impedance.
This will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in segmental phase angle.
The phase angle (kHz) will be measured by Inbody 970.
Measured: Before (baseline) and after treatment period (12 weeks).
Change in perception of knee joint stiffness.
This variable will be assessed using the rigidity subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire. It consists of two items. The perceived intensity of knee stiffness will be evaluated in two different situations: in the morning, immediately after waking up, and during the day, following a period of rest or inactivity, using the Likert scale (0: no stiffness; 1: mild stiffness; 2: moderate stiffness; 3: severe stiffness; 4: extreme stiffness) (total scale 0-8).
Measured: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Change in perception of knee functional capacity.
This variable will be assessed using the rigidity subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire.
It consists of 17 items. The difficulty in performing various activities-such as climbing or descending stairs, walking, bending, or carrying out daily tasks-will be evaluated using the Likert scale (0: no difficulty; 1: mild difficulty; 2: moderate difficulty; 3: severe difficulty; 4: extreme difficulty) (total scale 0-68).
Measured: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in the perception of the general health status of the knee
This variable will be assessed using the rigidity subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire.
It will be obtained by summing the scores of the three subscales: pain, stiffness, and physical function. The total score ranges from 0 to 96, reflecting the best and worst possible knee condition, respectively.
Measured: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Perception of pain in the hand joint
This variable will be assessed using the pain subscale of the Australian-Canadian Hand Osteoarthritis Index (AUSCAN) questionnaire. The questionnaire consists of 5 items that assess, over the previous 48 hours, the intensity of pain at rest and while grasping, lifting, turning, and squeezing objects, using a Likert scale (0: no pain; 1: mild pain; 2: moderate pain; 3: severe pain; 4: extreme pain).
Measured: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in perception of hand joint stiffness
This variable will be assessed using the pain subscale of the Australian-Canadian Hand Osteoarthritis Index (AUSCAN) questionnaire. It consists of 1 item that assesses, over the previous 48 hours, the intensity of hand stiffness upon waking, using a Likert scale (0: no stiffness; 1: mild stiffness; 2: moderate stiffness; 3: severe stiffness; 4: extreme stiffness).
Measured: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in perception of the functional capacity of the hand joint
This variable will be assessed using the pain subscale of the Australian-Canadian Hand Osteoarthritis Index (AUSCAN) questionnaire. It consists of 7 items that assess, over the previous 48 hours, the difficulty in turning, holding, opening, carrying, grasping, and squeezing various objects with the hand, using a Likert scale (0: no difficulty; 1: mild difficulty; 2: moderate difficulty; 3: severe difficulty; 4: extreme difficulty).
Measured: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in knee range of motion
This variable will be measured using a digital goniometer.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in the functional capacity of the hand joints
Hand grip strength will be measured, in kilograms, using the InGrip digital dynamometer.
Measured: Before (baseline), and after treatment period (12 weeks)
Changes in the speed when going up and down stairs.
This variable will measured by The "Stair Climb Test" , in which the volunteer must climb and descend 10 standard steps (between 15 and 20 cm) without the aid of a handrail. The time (minutes and seconds) taken by the volunteer to complete the test will be recorded.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in pain perception at the end of the Stair Climb Test
At the end, perceived pain will be measured using a 100 mm visual analog scale, where 0 indicates "no pain" and 100 indicates "all the pain you can experience".
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in plasma interleukin 6 (IL-6) concentration.
Plasma IL-6 levels will be measured by ELISA kits
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in plasma tumor necrosis alpha (TNF-a) concentration.
Plasma TNF-a levels will be measured by ELISA kit.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in plasma monocyte chemotactic protein 1 (MCP-1) concentration
Plasma MCP-1 levels will be measured ELISA kit.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in serum High-sensitivity C-reactive protein (hsCRP) concentration.
Serum hsCRP levels will be measured by chemiluminescence method.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of C-terminal telopeptide of type 1 collagen (CTX1).
Serum CTX1 will be measured by electrochemiluminescence method.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of N-terminal propeptide of type I collagen (PINP).
Serum PINP will be measured by electrochemiluminescence method.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of hyaluronic acid (HA).
Serum HA will be measured by ELISA kits.
Measured: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of cartilage oligomeric matrix protein (COMP).
Serum COMP will be measured by ELISA kits.
Measured: Before (baseline) and after treatment period (12 weeks).
Dietary control.
The intake of foods containing bioactive components that could alleviate pain will be assessed using an adapted food frequency questionnaire.
The following scale will be used: "I have not used it"; "1 time a week"; "2-4 times a week"; "5-6 times a week"; "7-10 times a week"; "10-20 times a week"; ">20 times a week"
Measured: Before (baseline), during (6 week) and after treatment period (12 weeks).
Changes in dietary supplement use.
The consumption of supplements and dietary products by the volunteers will be monitored through the analysis of the supplement and dietary product records in the case report form.
Measured: Before (baseline), during (6 week) and after treatment period (12 weeks).
Changes in concomitant medications.
The consumption of concomitant medication will be monitored through the analysis of the concomitant medication records in the case report form.
Measured: Before (baseline), during (6 week) and after treatment period (12 weeks).
Changes in pain-relieving medication use.
This will be assessed by recording concomitant medications in the data collection form.
Measured: Before (baseline), during (6 week) and after treatment period (12 weeks).
Physical activity levels.
This will be determined by analyzing the Physical Activity Questionnaire, Quick Physical Activity Classifier, adapted from the Generality of Catalonia (PEFS) guidelines.
Measured: Before (baseline), and after treatment period (12 weeks).
Monitoring of adverse effects.
The presence of adverse events reported by the participant in the data collection form will be recorded using the Adverse Effects Form.
Measured: During (6 week) and after treatment period (12 weeks).
Treatment adherence rate.
Treatment adherence will be calculated using the following formula: (number of capsules the volunteer should have taken / number of capsules actually taken) * 100
Measured: During (6 week) and after treatment period (12 weeks).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Jan 2026
- Study start10 Nov 2025
- Primary completionFeb 2027 (estimated)
- Study completionFeb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for OsteearthritisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomized, parallel, placebo-controlled, triple-blind nutritional intervention clinical study, with a 1:1:1:1 ratio between interventions.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Fundació Eurecat
- Sponsor type
- University, hospital or other
- Collaborators
- HISPANAGAR SA
- Responsible party
- Sponsor
- Investigators
- Antoni Caimari Palou, PhD, Principal investigator, UTNS (Eurecat, Reus)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07318896
- Sponsor's protocol ID
- AGARTROSIS
- Acronym
- AGARTROSIS
- Status last verified
- Dec 2025
- First submitted
- 20 Nov 2025
- Last updated
- 6 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- 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)
- ClinicalTrials.gov ID
- NCT07318896
- Acronym / sponsor ID
- AGARTROSIS / AGARTROSIS
- Conditions
- Osteearthritis, Joint Damage, Inflammation, Cartilage Damage
- Keywords
- Agar-Agar, undenatured collagen type II, Joint pain, knee pain
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- Fundació EurecatUniversity, hospital or other
- Collaborators
- HISPANAGAR SA
- Study start
- 10 Nov 2025 (actual)
- Primary completion
- Feb 2027 (estimated)
- Study completion
- Feb 2027 (estimated)
- First posted
- 6 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Joints-comprising bone, cartilage, ligaments, and synovial fluid-enable stable daily movement but may deteriorate with age, excess body weight, overuse, injury, or disease. Such degeneration, common from age 40 onward, underlies joint disorders like osteoarthritis, particularly in the knees, hips, hands, and spine, and is a major cause of chronic pain and disability. While antiinflammatory analgesics remain the standard approach to symptom control, they neither cure disease nor regenerate cartilage and can produce significant long-term adverse effects (gastrointestinal, hepatic, renal, and cardiovascular). These limitations motivate interest in natural or complementary strategies with safer profiles.
Within this context, marine algae, especially agar derived from red seaweed, have attracted attention for potential intestinal, metabolic, and joint benefits, aided by their fiber content. Another promising option is undenatured type II collagen (UC-II), the principal structural component of articular cartilage, whose endogenous production declines with age; clinical studies indicate that a daily intake of 40 mg UC-II can improve mobility, reduce pain, and enhance quality of life in individuals with osteoarthritis or exercise-related joint discomfort. Based on these considerations, an agar-agar supplement has been developed to relieve knee joint symptoms.
Detailed description
The primary objective of this study was to evaluate the effect of agar-agar (A-A), the combination of A-A with undenatured type II collagen (A+UC-II), and undenatured type II collagen (UC-II) on knee joint pain, assessed by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), in subjects with mild to moderate joint pain without a diagnosis of osteoarthritis, compared with a control compound.
The secondary objectives were to evaluate the effects of A-A, A+UC-II, and UC-II consumption on:
- Knee joint stiffness and functional capacity (subjective assessment).
- Overall perception of knee health (subjective assessment).
- Pain, stiffness, and functional capacity of the hand (subjective assessment).
- Range of motion of the knee.
- Functional capacity of the knee (objective assessment).
- Functional capacity of the hand (objective assessment).
- Frequency of medication use for joint pain relief (anti-inflammatories, analgesics).
- Inflammatory blood markers.
- Blood markers of collagen and bone metabolism.
- Body composition.
The primary endpoint is patient-reported knee joint pain, assessed using the Pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire.
This is a randomized, placebo-controlled, triple-blind, parallel-group nutritional intervention with an allocation ratio of 1:1:1:1. A total of 80 participants (men and women) will be enrolled. Following a pre-screening visit to verify inclusion and exclusion criteria, eligible participants will be randomly assigned to one of four groups (n=20 per group) to consume, once daily for 12 weeks, one of the following products: agar-agar (A-A), A-A+UC-II (A+UC-II), UC-II alone, or placebo.
Each participant will complete three in-person visits and one interim telephone follow-up: a pre-screening visit (eligibility assessment), a baseline visit to initiate the intervention, a mid-study telephone follow-up, and an end-of-study visit. The total duration per participant will be 13 weeks.
The primary endpoint is patient-reported knee joint pain, assessed using the Pain subscale of the WOMAC questionnaire.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 4
- Model description
- Randomized, parallel, placebo-controlled, triple-blind nutritional intervention clinical study, with a 1:1:1:1 ratio between interventions.
| Arm | Type | Receives |
|---|---|---|
| Agar-Agar (A-A) | Experimental | Dietary Supplement: Agar-AgarParticipants assigned to this group will receive agar-agar (A-A) supplementation and will take it for 12 weeks. |
| Agar-Agar + undenatured collagen type II (A+UC-II) | Experimental | Dietary Supplement: Agar-Agar and undenatured collagen type IIParticipants assigned to this group will receive agar-agar and undenatured collagen type II (A+UC-II) supplementation and will take it for 12 weeks. |
| undenatured collagen type II (UC-II) | Active comparator | Dietary Supplement: undenatured collagen type IIParticipants assigned to this group will receive undenatured collagen type II (UC-II) supplementation and will take it for 12 weeks. |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboParticipants assigned to this group will receive the placebo and will take it for 12 weeks. |
Who may qualify
- Ages
- 40 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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.
Key exclusion criteria (18 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Agar-AgarAlso: (A-A)2.4 g of agar-agar (Rhodophyceae group) presented in capsule form will be given. | Dietary supplement | Agar-Agar (A-A) |
| Agar-Agar and undenatured collagen type IIAlso: (A+UC-II)2.4 g of agar- agar + 40 mg of undenatured collagen type II, presented in capsule form will be given. | Dietary supplement | Agar-Agar + undenatured collagen type II (A+UC-II) |
| undenatured collagen type IIAlso: (UC-II)40 mg of undenatured collagen type II + 2.4 g of maltodextrin will be given in capsule form | Dietary supplement | undenatured collagen type II (UC-II) |
| Placebo2.4 g Maltodextrin will be given in capsule form | Dietary supplement | Placebo |
Primary outcome
Change in perception of knee joint pain.
Time frame: Before (baseline), during (6 weeks) and after treatment period (12 weeks).
This will be determined using the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire. The questionnaire assesses clinically meaningful changes in symptoms and physical disability in individuals with osteoarthritis or those experiencing joint discomfort. It evaluates the perceived intensity of knee pain using the Likert scale (0: no pain; 1: mild pain; 2: moderate pain; 3: severe pain; 4: extreme pain).
42 secondary outcomes
Body weight.
Time frame: at week 1.
Height.
Time frame: At week 1.
Body mass index (BMI) (kg/m^2).
Time frame: At week1.
Age.
Time frame: At week 1.
Changes in systolic and diastolic blood pressure and resting heart rate.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in body weight.
Time frame: Before (baseline) and after treatment period (12 weeks).
Change in BMI.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of body fat.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of body fat.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of muscle mass.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of muscle mass.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of bone mass.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in the amount of total body water.
Time frame: Before (baseline) and after treatment period (12 weeks).
Change in the amount of lean mass.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in bone mineral content.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in segmental impedance.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in segmental phase angle.
Time frame: Before (baseline) and after treatment period (12 weeks).
Change in perception of knee joint stiffness.
Time frame: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Change in perception of knee functional capacity.
Time frame: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in the perception of the general health status of the knee
Time frame: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Perception of pain in the hand joint
Time frame: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in perception of hand joint stiffness
Time frame: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in perception of the functional capacity of the hand joint
Time frame: Before (baseline) during ( 6 weeks) and after treatment period (12 weeks).
Changes in knee range of motion
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in the functional capacity of the hand joints
Time frame: Before (baseline), and after treatment period (12 weeks)
Changes in the speed when going up and down stairs.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in pain perception at the end of the Stair Climb Test
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in plasma interleukin 6 (IL-6) concentration.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in plasma tumor necrosis alpha (TNF-a) concentration.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in plasma monocyte chemotactic protein 1 (MCP-1) concentration
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in serum High-sensitivity C-reactive protein (hsCRP) concentration.
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of C-terminal telopeptide of type 1 collagen (CTX1).
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of N-terminal propeptide of type I collagen (PINP).
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of hyaluronic acid (HA).
Time frame: Before (baseline) and after treatment period (12 weeks).
Changes in serum levels of cartilage oligomeric matrix protein (COMP).
Time frame: Before (baseline) and after treatment period (12 weeks).
Dietary control.
Time frame: Before (baseline), during (6 week) and after treatment period (12 weeks).
Changes in dietary supplement use.
Time frame: Before (baseline), during (6 week) and after treatment period (12 weeks).
Changes in concomitant medications.
Time frame: Before (baseline), during (6 week) and after treatment period (12 weeks).
Changes in pain-relieving medication use.
Time frame: Before (baseline), during (6 week) and after treatment period (12 weeks).
Physical activity levels.
Time frame: Before (baseline), and after treatment period (12 weeks).
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Jan 2026.
- Technological Centre of Nutrition and Health. Eurecat\_ReusLink provided by the sponsor.
- Individual participant dataSharing planned: No
Related trials for Osteearthritis
Recruiting
Effects of Mobilized Balance Platform Exercises on Balance Parameters in Patients With Knee Osteoarthritis
Osteearthritis, Knee Arthritis, Osteoarthritis
Not yet recruiting
Tecar Therapy in Chronic Knee Osteoarthritis
Osteearthritis
Active, not recruitingPhase 4
Application of Autologous Stem Cells From Adipose Tissue in the Regeneration of Knee Joint Cartilage
Osteearthritis
Recruiting
Effects of Diagonal Proprioceptive Neuromuscular Facilitation Patterns on Pain and Functional Outcomes in Patients With Knee Osteoarthritis
Knee Osteoarthristis, Osteearthritis
Not yet recruitingObservational study
Value of Adding T2 Mapping Routine MRI in Assessment of Knee Articular Cartilage Early Osteoarthritis
Osteearthritis, OA
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Antoni Caimari Palou, PhD principal investigator
UTNS (Eurecat, Reus)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Agar-Agar, Agar-Agar and undenatured collagen type II and undenatured collagen type II in people with Osteearthritis and Joint Damage, run by Fundació Eurecat at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Antoni Caimari Palou, PhD (0034 977 300 805, antoni.caimari@eurecat.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in perception of knee joint pain. (time frame: Before (baseline), during (6 weeks) and after treatment period (12 weeks).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Jan 2026.