Trial reportNutrients2022
Effects of l-Arginine Plus Vitamin C Supplementation on Physical Performance, Endothelial Function, and Persistent Fatigue in Adults with Long COVID: A Single-Blind Randomized Controlled Trial.
Trial report in Nutrients, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
61 citing papers in PubMed, 1 synthesis or guideline pooled it, 89 citations in OpenAlex.
- Interventions for the management of long covid (post-covid condition): living systematic review.BMJ (Clinical research ed.) · 2024Pooled it
- Effect of L-Citrulline Supplementation on Endothelial Function and Body Composition in Post-COVID-19 Syndrome: A Randomized Clinical Trial.Nutrients · 2026Trial
- Trial
- Effects of l-Arginine Plus Vitamin C Supplementation on l-Arginine Metabolism in Adults with Long COVID: Secondary Analysis of a Randomized Clinical Trial.International journal of molecular sciences · 2023Trial
- Frailty before disease onset: risk of mortality and chronic conditions in disease-free middle-aged adults.GeroScience · 2026Article
- Understanding the long-term neurological effects of SARS-CoV-2 infection.Nature reviews. Neurology · 2026Review
- Argininosuccinate synthase 1 (ASS1) orchestrates arginine metabolism and ornithine production to modulate CHIKV infection.Journal of virology · 2026Article
- High-dose vitamin C: A promising anti-tumor agent, insight from mechanisms, clinical research, and challenges.Genes & diseases · 2026Review
- The Role of L-Arginine and Liposomal Vitamin C Supplementation as an Adjunct in Seasonal Respiratory Viral Infection Recovery.Advances in respiratory medicine · 2026Review
- Influence of lifestyle factors on susceptibility, disease course and recovery from post COVID-19 syndrome: a scoping review.BMJ public health · 2026Article
- Editorial: Long- and post-COVID syndromes: immune mechanisms and therapeutic strategies.Frontiers in immunology · 2026Article
- Nitric Oxide at the Nexus of ACE2 Biology and COVID-19: Implications for Cardiovascular and Neurodegenerative Comorbidities.Physiological research · 2025Review
- Physical activity during COVID-19 pandemic: A 5-year retrospect.Sports medicine and health science · 2025Review
- Insights into potential therapeutic approaches for long COVID.Frontiers of medicine · 2025Article
- Persistence of symptoms in long-COVID: follow-up trajectories of 30 symptoms in 755 patients from a national multicenter study from Italy.Internal and emergency medicine · 2025Article
- Longitudinal relationships between changes in post-COVID mental fatigue and neuropsychiatric symptoms across distinct recovery trajectories.Inflammopharmacology · 2025Article
- Post-COVID Condition and Neuroinflammation: Possible Management with Antioxidants.Antioxidants (Basel, Switzerland) · 2025Review
- Interventions for Long COVID: A Narrative Review.Journal of general internal medicine · 2025Review
- A Comprehensive Scoping Review on Diet and Nutrition in Relation to Long COVID-19 Symptoms and Recovery.Nutrients · 2025Article
- Therapeutic options for the treatment of post-acute sequelae of COVID-19: a scoping review.BMC infectious diseases · 2025Article
1 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
22 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Long COVID, a condition characterized by symptom and/or sign persistence following an acute COVID-19 episode, is associated with reduced physical performance and endothelial dysfunction. Supplementation of l-arginine may improve endothelial and muscle function by stimulating nitric oxide synthesis. A single-blind randomized, placebo-controlled trial was conducted in adults aged between 20 and 60 years with persistent fatigue attending a post-acute COVID-19 outpatient clinic. Participants were randomized 1:1 to receive twice-daily orally either a combination of 1.66 g l-arginine plus 500 mg liposomal vitamin C or a placebo for 28 days. The primary outcome was the distance walked on the 6 min walk test. Secondary outcomes were handgrip strength, flow-mediated dilation, and fatigue persistence. Fifty participants were randomized to receive either l-arginine plus vitamin C or a placebo. Forty-six participants (median (interquartile range) age 51 (14), 30 [65%] women), 23 per group, received the intervention to which they were allocated and completed the study. At 28 days, l-arginine plus vitamin C increased the 6 min walk distance (+30 (40.5) m; placebo: +0 (75) m, p = 0.001) and induced a greater improvement in handgrip strength (+3.4 (7.5) kg) compared with the placebo (+1 (6.6) kg, p = 0.03). The flow-mediated dilation was greater in the active group than in the placebo (14.3% (7.3) vs. 9.4% (5.8), p = 0.03). At 28 days, fatigue was reported by two participants in the active group (8.7%) and 21 in the placebo group (80.1%; p < 0.0001). l-arginine plus vitamin C supplementation improved walking performance, muscle strength, endothelial function, and fatigue in adults with long COVID. This supplement may, therefore, be considered to restore physical performance and relieve persistent symptoms in this patient population.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.