An interventional study of Omega-3 oil with 2% Free Fatty Acids and Vegatable oil in Respiratory Infections, sponsored by Landspitali University Hospital. Recruiting at 1 site in Iceland. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-28.
Sponsored by Landspitali University Hospital · Not applicable, Interventional, and Prevention
The purpose of this study is to investigate whether fish oil containing free fatty acids affects people's susceptibility to viral infections such as colds, influenza, and COVID-19, as well as the course of these illnesses. Omega Cold is purified fish oil with 2% added free fatty acids, making it similar in that respect to less-purified fish oils. Participants aged 18-80 in generally good health will be recruited through Matís' consumer mailing list and social media advertisements. A total of 400 participants are planned: 100 in the winter of 2025-2026 and 300 in the winter of 2026-2027. Participants will be randomly assigned to two equal groups. One group will take Omega Cold orally twice a day for four months, while the other receives a placebo (vegetable oil) taken in the same way. They will not be asked to change any other habits. All participants will report weekly on their health and any cold or flu symptoms during the time they take the oil, using short questionnaires. The study is scheduled to begin in December 2025, when the oil will be sent to participants.
The purpose of the Omega Cold fish oil study is to determine whether fish oil enriched with free fatty acids affects people's susceptibility to viral infections, such as colds, flu or COVID, and the illnesses caused by such infections.
Free fatty acids are present in untreated fish oil. However, the fish oil most commonly on the market today has been purified of free fatty acids. Omega Cold fish oil is purified fish oil with added free fatty acids in 2% concentration. This study is the first step in investigating whether fish oil with free fatty acids affects how often people get sick from viral infections, and whether consuming the fish oil affects the progression of the illness.
Participants in the study are recruited by sending an email to Matís' consumer list and through advertisements on social media. The conditions for participation are to be between the ages of 18-80 and in generally good health. The aim is for 400 people to participate in the study - 100 in the winter of 2025 - 2026 and 300 in the winter of 2026 - 2027.
The participants will be divided into two equal groups. One group will receive Omega Cold fish oil to take twice a day for four months. The other group is a placebo group and will receive vegetable oil to take in the same way. Participants will not be asked to change anything else in their consumption or behavior. All participants will be asked to record information about their health with regard to cold and flu symptoms weekly during the time they take the oil using short questionnaires.
751 studies on the registry are indexed under Respiratory Tract Infections; 114 are open to participants now.
This study's planned enrollment of 400 is above the median of 200 across 540 interventional studies indexed under Respiratory Tract Infections.
Browse Respiratory Tract Infections studies →Landspitali University Hospital is the lead sponsor of 21 studies on the registry; 6 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Omega-3 oil enriched with Free Fatty Acids (2%)
Dietary Supplement: Omega-3 oil with 2% Free Fatty Acids
Vegetable oil as a placebo
Dietary Supplement: Vegatable oil
Omega-3 oil enriched with Free Fatty Acids (2%) for oral intake
Vegetable oil as placebo
Respiratory infections
Participants will complete a short weekly questionnaire reporting any respiratory infection symptoms they experienced in the past seven days. If symptoms are present, they will be asked to provide additional details, including the type of symptoms, their duration, and their severity rated on numerical scales from 1 to 7 with 1 being mild and 7 being severe.
Time frame: Four months
Plan to share: No
No publications or documents are linked to this record.
Started Dec 2025 (actual). Primary completion is estimated for Apr 2027, 16 months after the start.
Of 116 non-industry interventional studies with no phase under Respiratory Tract Infections, half reached primary completion within 13 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 30. This study's planned 16 months is above that.
Counting every sponsor, half of 143 studies reached it within 11 months; a quarter within 6 and three quarters within 29.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Respiratory Tract Infections →
Landspitali University Hospital