An NAD increase is not the same as recovery from long COVID. A 2025 randomized study of oral NR is useful because it measured both NAD and symptoms, and the results did not move together in the same way.
The trial did not find a significant benefit versus placebo for cognition, fatigue, sleep, or mood. Exploratory improvements reported in another analysis need that context before they are used to promote a supplement or infusion.
The controlled trial raised blood NAD without demonstrating a symptom benefit over placebo. Individualized long-COVID care remains important.
What was actually tested?
The published trial randomized 58 adults at one center to different sequences of NR and placebo, followed by an NR phase. It tested oral NR, not direct-NAD injections. Blood NAD increased, but the main between-group symptom comparisons were not significant. Dropout was substantial, particularly during longer NR follow-up, which makes the estimates less secure and limits conclusions about sustained use.
Why do some summaries sound more positive?
The researchers also performed exploratory analyses of changes from participants’ own starting measurements while taking NR. Those comparisons are different from the randomized placebo comparison and were not adjusted for testing multiple outcomes. Together with industry support disclosed in the paper, these details belong beside a positive headline. Exploratory findings can justify a larger trial; they do not establish that the product caused recovery.
What does a higher blood NAD result tell you?
It can help show that a precursor changed the measured biochemical system. It does not tell you that post-exertional symptoms, cognition, or daily function improved. The testing guide explains why a laboratory number should not become a stand-alone treatment target. A negative symptom comparison also does not mean a person’s symptoms are unreal; it describes the evidence for this intervention.
What care questions matter now?
The CDC’s clinical guidance emphasizes assessment and management tailored to a person’s symptoms and conditions. Long COVID can involve several systems, so fatigue should not automatically be labeled a NAD deficiency. Keep the discussion focused on the problems affecting daily life, relevant investigations, and a care plan that can be adjusted as symptoms change.
Why exercise advice needs care
Post-exertional malaise can follow even limited physical or mental effort, sometimes with a delay. CDC guidance recognizes this pattern. A supplement marketed for energy should not be used as a reason to push through worsening symptoms or apply a healthy-athlete training plan. Discuss activity management with a clinician familiar with your symptoms. Our exercise article concerns different study populations.
Before buying a long-COVID NAD package
Ask for evidence supporting the exact ingredient, route, and promised outcome. Find out the complete cost, follow-up arrangements, and what happens if there is no benefit. No clinic can turn an oral biomarker result into proof for its infusion simply by using the same NAD terminology. Compare energy claims, route differences, and before-and-after stories.
Sources & reading notes
Primary sources checked September 18, 2026. Provider pages describe their own offers; inclusion does not verify a product or its results.
- Wu et al. (2025): randomized NR trial in long COVID 58 randomized; NAD increased without significant between-group symptom benefit. Exploratory analyses, dropout, and funding require context.
- CDC: long COVID clinical guidance Individual symptom management and post-exertional malaise context; not evidence of NAD treatment efficacy.
- FDA: questions and answers on dietary supplements Regulatory categories and limits of premarket review.
Educational information, not individualized medical advice. We do not claim medical review or firsthand treatment experience. Read our review standards and commercial disclosure.