Summary
| Direction in Long COVID | ↓ Reduced — lower than in the comparison group |
|---|---|
| Category | Metabolic |
| Also described as | Amino acid |
| Compared against | HC, R (healthy controls, recovered individuals without persistent symptoms) |
| Associated symptoms | Immune-metabolic coupling |
| Test type | Blood test (serum / plasma / whole blood) |
| Source | Saito et al. 2024 — doi:10.3389/fimmu.2024.1341843 |
| Condition atlas | Long COVID Biomarker Atlas |
Trials, interventions and tests
In clinical-trial registrations this marker maps to the outcome term The change in level of glutamine (Gln) at each hippocampus from baseline to the end of 8 weeks. (2 registered trials use a matching outcome measure).
Clinical trials using Glutamine as an outcome
- NCT03496961: Yan Nian Jiu Zhuan Fa Improve Chronic Fatigue Syndromes (Unknown)
Outcome measure: Neuropeptide Y - NCT07357688: The Effect of Acupuncture Therapy on Cognitive Function in Post-COVID-19 Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (Not Yet Recruiting)
Outcome measure: The change in level of glutamine (Gln) at each hippocampus from baseline to the end of 8 weeks.
Interventions studied alongside this marker
Hypothesis-generating links from trial outcome usage and literature co-occurrence. Not treatment recommendations.
- Acupuncture — 1 trial, 6 PubMed co-citations
e.g. Evaluation of electroacupuncture acupoint selection's potential in the treatment of inflammatory bowel…
Also sold as a nutrient or supplement
Glutamine (L-Glutamine) (amino acid). Common recovery amino acid powder. This tag means the analyte is also available orally; it is not a product endorsement and a low or high level does not by itself justify supplementation.
Related Metabolic markers in Long COVID
- Asparagine ↓
- Arginine ↓
- Aspartate ↓
- Histidine ↓
- Sarcosine ↓
- TCA cycle intermediates ↑
- Serine ↓
- Kynurenine ↑
Full list: Long COVID Biomarker Atlas.
Frequently asked questions
Is Glutamine high or low in Long COVID?
Reduced. Studies summarised in the OSMF atlas report lower Glutamine in Long COVID than in healthy controls, recovered individuals without persistent symptoms. Source: Saito et al. 2024.
What symptoms is Glutamine associated with in Long COVID?
The cited literature associates this marker with Immune-metabolic coupling. These are population-level associations and do not mean the marker causes the symptoms.
Which test measures Glutamine?
It is measured as a blood test (serum / plasma / whole blood). Many of the cited studies used research-grade assays, so clinical availability may vary.
Is one abnormal Glutamine result diagnostic of Long COVID?
No. No single biomarker is diagnostic of Long COVID. Glutamine findings come from group comparisons, overlap considerably between patients and controls, and vary with study design, timing and comparison group. A result should be interpreted by a clinician alongside symptoms, history and other tests.
Cite this page
Subscribe on Substack
Last reviewed: 2026-06-29 · Page generated from long-covid.json · Browse: Long COVID atlas · Biomarker Index · All marker pages
Disclaimer: This page is an educational synthesis of published, peer-reviewed research and is not medical advice. Biomarker findings vary across studies with case definitions, comparison groups, timing and assay methods. Direction of change reflects the predominant finding in the cited source and does not establish a diagnostic threshold. Discuss any test result with a qualified clinician.