An interventional study of Experimental Product and Control placebo in Long COVID, sponsored by Universidad Católica San Antonio de Murcia. Not yet recruiting at 1 site in Spain. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-02-09.
Sponsored by Universidad Católica San Antonio de Murcia · Not applicable, Interventional, and Other
A controlled, randomized clinical trial is proposed to demonstrate the effectiveness of the experimental product in controlling hepato-pulmonary inflammation and neurovascular encephalic inflammation, which may constitute the etiopathogenic basis of persistent COVID. In addition, an individualized training program will be implemented for each participant in order to improve chronic symptoms and, consequently, their quality of life.
Randomized, placebo-controlled, double-blind clinical trial with four parallel arms based on the product consumed (placebo or experimental product) and the performance of physical exercise (exercise or no exercise), designed to analyze the effectiveness of the product under investigation in reducing chronic immune-mediated inflammatory status in subjects who have had SARS-CoV-2 infection and present persistent symptoms 3 months after the onset of the infectious process.
The efficacy of the experimental product, consumed over a period of 4 months, will be determined in terms of reducing chronic inflammation and improving the quality of life of people suffering from this condition.
Clinical manifestations and chronic symptoms, quality of life, response to the individualized physical exercise program, and product safety will be taken into account.
520 studies on the registry are indexed under Post-Acute COVID-19 Syndrome; 186 are open to participants now.
This study's planned enrollment of 40 is below the median of 60 across 361 interventional studies indexed under Post-Acute COVID-19 Syndrome.
Browse Post-Acute COVID-19 Syndrome studies →Universidad Católica San Antonio de Murcia is the lead sponsor of 132 studies on the registry; 18 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Subjects in this group will consume a placebo product (maltodextrin) with the same organoleptic characteristics as the investigational product.
Dietary Supplement: Control placebo · Other: No Physical Exercise
Subjects in this group will consume the investigational product (experimental product composed of a combination of six natural extracts: grapefruit extract, apigenin, orange extract, luteolin, yerba mate extract, and olive leaf extract).
Dietary Supplement: Experimental Product · Other: No Physical Exercise
During the study, subjects must consume the experimental product and also follow a training program. A multi-component program will be carried out during the 4 months of product consumption. Sessions will last 60 minutes and will be held 2-3 times per week.
Dietary Supplement: Experimental Product · Other: Physical exercise
During the study, subjects must consume the placebo product and also follow a training program. A multi-component program will be carried out during the 4 months of product consumption. Sessions will last 60 minutes and will be held 2-3 times per week.
Dietary Supplement: Control placebo · Other: Physical exercise
Supplement consisting of orange extract, apigenin, luteolin, yerba mate extract, grapefruit extract, and olive leaf extract.
Product with identical characteristics to the experimental product.
During the study, subjects will have to develop a training program. A multicomponent program will be carried out during the 4 months of product consumption. The sessions will last 60 minutes and will be held 2-3 times per week.
During the study, subjects will only consume the product assigned to them in the randomization.
Immunoinflammatory profile
Antibody assay for molecular biomarkers of the brain-liver-lung axis, blood-brain barrier, immunometabolic pathways, and immune-inflammatory and immuno-angiogenic cardiac remodeling.
Time frame: Blood samples will be taken twice, once at baseline, at the beginning of the trial and once at the end after 120 days of product intake.
Clinical signs
The number of clinical manifestations, the type of manifestation, intensity according to the visual analog scale from 0 to 10, and duration of the symptomps. The clinical manifestations will be those felt by the subject.
Time frame: It will be recorded twice, before starting the consumption of the product and before the end of consumption (120 days)
Short Form 12 Health Survey
Measured by SF-12 questionnaire. Scale 0-100%
Time frame: It will be measured twice, once at baseline and at the end of the study after 120 days of consumption.
Sleep quality
Measured by Pittsburgh test
Time frame: Progress will be measured after 120 days of consumption.
Sleep efficiency
Measured by accelerometry, with Actigraph wGT3X-BT
Time frame: Progress will be measured after 120 days of consumption.
Fatigue
Measured with Fatigue Severity Scale (FSS). Rated on a 7-point Likert scale (1=strongly disagree, 7=strongly agree), a mean score of \\(\\ge 4\\) typically indicates a moderate to high level of fatigue.
Time frame: Progress will be measured after 120 days of consumption.
Dyspnea
It will be measured with Modified Medical Research Council (mMRC)
Time frame: Progress will be measured after 120 days of consumption.
Depression
It will be measured with Beck Depression Inventory (BDI). Scores are calculated by adding up the responses to 21 items, with a range from 0 to 63, and scores are interpreted by severity levels: 0-13 (minimal), 14-19 (mild), 20-28 (moderate), and 29-63 (severe).
Time frame: Progress will be measured after 120 days of consumption.
Anxiety
It will be measured with the State-Trait Anxiety Inventory (STAI). The STAI (State-Trait Anxiety Inventory) assesses transient (state) and stable (trait) anxiety using 40 items (20 per subscale) with a Likert-type score from 0 to 3. The total score per subscale ranges from 0 to 60, with higher scores indicating greater anxiety.
Time frame: Progress will be measured after 120 days of consumption.
Hospital Anxiety and Depression
Measured with Hospital Anxiety and Depression Scale (HADS). It is a self-administered instrument with 14 items (7 for anxiety, 7 for depression) that is scored from 0 to 3, with a maximum total of 21 points per subscale. A score of 7 or less indicates normality, 8-10 indicates a borderline case, and 11 or above indicates a probable case of anxiety or depression.
Time frame: Progress will be measured after 120 days of consumption.
Stress level
Perceived stress scale (PSS). Measures stress levels over the past month on a scale of 0 to 56. The higher the score, the greater the perceived stress. Typical interpretive ranges include low stress (0-13), moderate stress (14-26), and high stress (27-40+).
Time frame: Progress will be measured after 120 days of consumption.
Cardiorespiratory fitness.
A submaximal test will be performed.
Time frame: Progress will be measured after 120 days of consumption.
The Rate of Force Development
The Rate of Force Development (RFD) measures the speed at which the neuromuscular system generates maximum force in a short period of time (typically in the first 100-200 ms). It is a key indicator of explosive strength and power, vital in fast movements, jumps, sprints, and climbing.
Time frame: Progress will be measured after 120 days of consumption.
Maximum Voluntary Isometric Contraction
Maximum Voluntary Isometric Contraction (MVIC) is the gold standard for measuring muscle strength, involving maximum contraction without joint movement (isometric). It is used to evaluate muscle activation using electromyography, comparing the percentage of effort against the muscle's maximum possible strength.
Time frame: Progress will be measured after 120 days of consumption.
Body composition
It is a control variable. Measured by bioimpedance.
Time frame: The test will be measured at baseline and after 16 weeks of consumption.
Liver safety variables
It is a blood test that measures the presence of some enzymes, proteins and bilirubin in the blood, with the aim of determining if there is any alteration in the liver. Enzyme GPT, GOT, Gamma GT, LDH, alkaline phosphatase and bilirubin (UI/L)
Time frame: Hematological samples were taken before (day 0) and after consumption of the product (day 120) both in the control group and in the experimental group.
Adverse events
It will be evaluated only at the end of the study.
Time frame: After 16 weeks of consumption.
Plan to share: No
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Universidad Católica San Antonio de Murcia