LOS ANGELES, Calif. — Niagen Bioscience, Inc. (NASDAQ: NAGE), the global authority on NAD+ science and healthy aging, announced new clinical findings from the first randomized controlled trial evaluating daily supplementation with Niagen, the company’s patented nicotinamide riboside (NR) ingredient, in individuals with long COVID. The study, published in The Lancet journal eClinicalMedicine, showed that Niagen significantly increased NAD+ levels and supported improvements from baseline in executive functioning, fatigue, depression, and sleep quality among some participants.
The 58-person randomized, double-blind, placebo-controlled study was led by Edmarie Guzmán-Vélez, PhD, formerly of Massachusetts General Hospital’s Department of Psychiatry and the McCance Center for Brain Health, and now an Assistant Professor in the Department of Neurology at the Robert Wood Johnson Medical School and the Center for Health Aging Research at Rutgers University.
“These findings demonstrate that ten weeks of Niagen NR supplementation increased NAD+ levels and improved long COVID symptoms of fatigue, sleep quality, and depression, compared to symptoms before treatment,” said Rob Fried, Chief Executive Officer of Niagen Bioscience. “As part of our mission to advance the science of cellular health, we are pleased to see Niagen NR used in research exploring the lasting impact of COVID-19 and look forward to future studies that further our understanding of NAD+ augmentation in recovery and resilience.”
Long COVID remains a widespread condition with no established treatment options. According to the U.S. Centers for Disease Control and Prevention, 5.3 percent of U.S. adults reported active long COVID symptoms between August and September 2024.
“Our goal with this study was to understand whether increasing NAD+ levels with NR could improve cognitive performance primarily, but also other common symptoms in individuals with long COVID,” said Dr. Guzmán-Vélez. “We saw encouraging within-group improvements in fatigue, sleep, and mood, although we did not observe statistically significant differences between people taking NR and those taking a placebo. These findings suggest that restoring NAD+ remains a promising avenue for recovery and advancing our understanding of how to help individuals affected by long COVID. More research is needed to confirm and expand on these findings.”
Researchers note that long COVID is associated with immune dysregulation, mitochondrial dysfunction, oxidative stress, impaired cellular energy metabolism, and decreased NAD+, a molecule essential for energy production and cellular repair. These biological disruptions contribute to symptoms such as fatigue, cognitive impairment, sleep disturbance, muscle pain, anxiety, and depression.
“Long COVID presents with a wide range of symptoms because coronaviruses disturb NAD+ and thereby disturb multiple organ systems,” said Charles Brenner, PhD, Alfred E Mann Family Foundation Chair in Diabetes and Cancer Metabolism at City of Hope, Chief Scientific Advisor to Niagen Bioscience, and study co-author. “What is encouraging is that despite variability among patients, we observed consistent signals of improvement with elevation of NAD+ levels. This suggests that restoring the NAD+ system can restore multiple biological pathways implicated in long COVID — including mitochondrial function, inflammation, and cellular repair. It is a compelling indication that NAD+ biology can be effectively targeted in conditions of metabolic stress such as long COVID.”
The 24-week trial assessed whether elevating NAD+ levels with Niagen NR could support cognitive and symptomatic recovery. Participants were randomized to receive either Niagen NR at 2,000 mg per day for 20 weeks or placebo for 10 weeks followed by Niagen NR for an additional 10 weeks. Cognitive performance was evaluated using validated assessments such as the Everyday Cognition scale, the Repeatable Battery for the Assessment of Neuropsychological Status, and the Trail Making Test-B. Fatigue, mood, and sleep quality were measured using FSS, BDI, BAI, and PSQI scales.
The study found NAD+ levels increased up to 3.1-fold after 5–10 weeks of supplementation. Exploratory analyses showed within-group improvements in fatigue severity, sleep quality, and depressive symptoms after 10 weeks of Niagen NR. Niagen NR was well tolerated, with adverse events similar between active and placebo groups. The study did not meet statistical significance between groups, which investigators attributed to the small sample size and high dropout rates.
The results mark the first evidence from a randomized controlled trial showing that Niagen NR can safely increase NAD+ levels in individuals with long COVID. While larger clinical studies are needed, these findings support NAD+ restoration as a measurable biological response with potential therapeutic relevance for long COVID and other post-viral conditions involving impaired energy metabolism.
The study was funded by the McCance Center for Brain Health at Massachusetts General Hospital and Niagen Bioscience. Niagen Bioscience partially funded the study and supplied Niagen NR and placebo materials but did not participate in study design, execution, analysis, or publication decisions.
