Niagen Bioscience has shared promising results from the first-of-its-kind clinical trial published in The Lancet.
The study demonstrates that daily supplementation with Niagen, Niagen Bioscience’s patented nicotinamide riboside (NR) ingredient, significantly increased NAD+ levels and improved executive functioning, fatigue, depression and sleep quality when compared to baseline levels, in some individuals with long COVID.
However, statistically significant differences between the Niagen NR and placebo groups were not observed for primary or secondary outcomes — likely due to the small sample size and high dropout rates resulting from reinfection, relocation and medication changes, which reduced statistical power.
Key takeaways
- NAD+ levels increased up to 3.1-fold after 5-10 weeks of Niagen NR supplementation,
- Participants showed improvements in fatigue, sleep quality and depressive symptoms after ten weeks,
- Niagen NR was well-tolerated, with no major safety concerns,
- While between-group differences were not significant, within-group results showed meaningful symptom improvement and measurable NAD+ restoration,
- The study is the first randomised controlled trial showing that Niagen NR safely elevates NAD+ levels in people with long COVID,
- Findings support the potential therapeutic role of NAD+ in post-viral recovery and energy metabolism,
- Larger, placebo-controlled studies are needed to confirm these early results.
The study was led by Dr Edmarie Guzmán-Vélez, Assistant Professor in the Department of Neurology at the Robert Wood Johnson Medical School and the Centre for Health Ageing Research (CHAR) at the Institute for Health, 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, CEO 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 and NAD+
Long COVID continues to affect a significant number of individuals around the globe, with no proven treatments available.
According to the US Centers for Disease Control and Prevention (CDC), between August and September 2024, 5.3% of adults in the US reported that they are currently experiencing long COVID.
A multi-system disorder, long COVID symptoms persist months or years after infection, including common fatigue, breathlessness, cognitive impairment or “brain fog”, muscle aches, depression and anxiety
Emerging evidence suggests that interacting mechanisms underlie long COVID, including immune dysregulation, mitochondrial dysfunction, oxidative stress, disrupted cellular energy metabolism and depletion of NAD+, a molecule crucial for cellular energy and repair.
"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."
“Long COVID presents with a wide range of symptoms as coronaviruses disturb NAD+ and thereby disturb multiple organ systems,” said Dr Charles Brenner, 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.”
Study overview
The 24-week, randomised, double-blind, placebo-controlled, parallel group study analysed the effects of elevating NAD+ with Niagen NR supplementation on cognitive and symptomatic recovery in individuals with long COVID.
A total of 58 non-hospitalised adults (mean age, 45.1 years) with persistent symptoms following COVID-19 infection were randomised to receive either Niagen NR (2,000 mg/day) for 20 weeks or placebo for ten weeks, followed by Niagen NR for an additional ten weeks.
The study included a two-week placebo lead-in period and a two-week follow-up period.
The primary endpoint analysed the change in cognitive performance, measured using validated scales and tests, including the Everyday Cognition (ECog), Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Trail Making Test-B (TMT-B).
Secondary endpoints were assessed using standardised scales to evaluate fatigue, mood and sleep quality (FSS, BDI, BAI and PSQI).