An interventional study of CICR-NAM in Post COVID Syndrome Long Covid, sponsored by University Hospital Schleswig-Holstein. Recruiting at 1 site in Germany. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by University Hospital Schleswig-Holstein · Not applicable, Interventional, and Supportive care
In patients with post-COVID syndrome, changes in tryptophan metabolism, energy metabolism, and the gut microbiome may occur. In an earlier nutritional study, patients with COVID-19 recovered their physical performance more quickly when taking nicotinamide (vitamin B3). Patients who responded to nicotinamide also developed post-COVID syndrome less frequently. At the University Hospital Schleswig-Holstein in Kiel, special nicotinamide tablets (CICR-NAM) were developed that release the active substance selectively in the lower intestine and have been shown to be very well tolerated in several studies.
Patients with post-COVID syndrome and documented tryptophan deficiency may therefore take one tablet (500 mg) of CICR-NAM daily for up to approximately 4 months as a food for special medicinal purposes within the therapy groups of the outpatient clinic for patients with post-COVID syndrome at the University Hospital Schleswig-Holstein in Kiel. This intake is far below the Upper Level defined by the European Food Safety Authority for lifelong daily intake (900 mg per day). Therefore, there are no safety concerns. CICR-NAM intake is intended to complement the therapy group programme by supporting energy metabolism.
In the COVit-2 study (DRKS00021214), daily intake of two tablets containing a total of 1,000 mg nicotinamide (500 mg conventional nicotinamide and 500 mg controlled-ileocolonic-release nicotinamide, CICR-NAM) in patients with acute COVID-19 was associated with a significantly faster improvement in physical performance after two weeks compared with placebo. Parallel effects on the gut metagenome suggested that specifically the ileocolonically released nicotinamide from CICR-NAM tablets could counteract COVID-19-associated disturbances in the metabolism of the essential amino acid tryptophan and in the gut microbiome. In the placebo group, gene expression related to the microbial tryptophan biosynthesis pathway as well as redox and salvage pathways of the central metabolic coenzyme nicotinamide adenine dinucleotide (NAD+) was significantly increased at week 2, whereas these deviations in the metagenome were not observed in patients receiving nicotinamide supplementation.
At the 6-month follow-up of COVit-2 participants, patients who benefited from nicotinamide administration (responders) developed post-COVID syndrome significantly less frequently. Because disturbances in tryptophan metabolism are well described in both COVID-19 and PCS, a low tryptophan level may serve as an easily measurable surrogate parameter for an increased nicotinamide requirement in these conditions.
There is currently no satisfactory treatment for patients with PCS. They experience significant distress and often have a permanent disability. Given the disturbances in tryptophan metabolism and the gut microbiome observed in PCS, supplementation with CICR-NAM may help restore physical performance. Therefore, a nutritional observational study offering 500 mg/day CICR-NAM as a food for special medicinal purposes for up to approximately 4 months will be conducted within the therapy groups of the PCS outpatient clinic at UKSH Campus Kiel for patients with documented tryptophan deficiency. A placebo-controlled clinical trial with CICR-NAM in PCS is planned, but it will not be available for recruitment in the near future. The present observational study is intended as an interim option until the clinical trial begins and is also expected to provide insights into the feasibility of such an intervention.
604 studies on the registry are indexed under Post-Acute COVID-19 Syndrome; 201 are open to participants now.
This study's planned enrollment of 100 is above the median of 60 across 416 interventional studies indexed under Post-Acute COVID-19 Syndrome.
Browse Post-Acute COVID-19 Syndrome studies →University Hospital Schleswig-Holstein is the lead sponsor of 163 studies on the registry; 25 are open to participants now.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Oral administration of CICR-NAM (controlled-ileocolonic-release nicotinamide) as a food for special medical purposes, one film-coated tablet (500 mg) daily for up to approximately 4 months, embedded in the therapy groups of the PCS outpatient clinic at UKSH Campus Kiel.
Dietary Supplement: CICR-NAM
Oral administration of CICR-NAM (controlled-ileocolonic-release nicotinamide) as a food for special medical purposes, one film-coated tablet (500 mg) daily for up to approximately 4 months, embedded in the therapy groups of the PCS outpatient clinic at UKSH Campus Kiel
Serum tryptophan level
Serum tryptophan level (µmol/L) as a longitudinal marker of tryptophan and NAD+ metabolism during CICR-NAM supplementation. Assessment time points: therapy group session 1 (start of participation, screening for reduced serum tryptophan, T1), session 2 (start of supplementation, T2), session 3 (after approximately 1 month of supplementation, T3), and session 6 (end of the therapy group, after approximately 4 months, T4). Method: quantitative determination of serum tryptophan (UKSH laboratory diagnostics)
Time frame: From T1 (start of participation, screening for reduced serum tryptophan) to T6 (end of the therapy group) approximately 5 month.
Plan to share: No
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Post-Acute COVID-19 Syndrome →
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