NAD+ for long COVID and post-viral fatigue: encouraging idea, unproven treatment

Why NAD+ was proposed

When a virus infects a cell, the cell's defenses switch on a family of enzymes called PARPs. These enzymes use NAD+ as fuel. Laboratory studies of coronavirus infection found that this response can deplete NAD+ in infected cells and disrupt the wider NAD+ system.

Researchers reasoned that if NAD+ stays low after infection, energy production and immune regulation could suffer, which might contribute to lingering fatigue. Restoring NAD+ became a plausible target. Plausible is not the same as proven, and the human data are still thin.

Researchers have also suggested that low NAD+ could keep the immune system in a state of low-grade inflammation, another possible contributor to fatigue.

What human studies have tried

Most studies have used oral NAD+ precursors such as nicotinamide riboside, sometimes in combination products with several other ingredients. Some reported improvements in fatigue scores, but when a product contains many ingredients, it is impossible to tell which one helped. Other trials found no clear difference from placebo on their main measures.

Older studies in chronic fatigue syndrome used oral NADH, alone or combined with coenzyme Q10, in small groups over a few weeks, with modest results. No controlled trial has tested subcutaneous or IV NAD+ for long COVID or post-viral fatigue. Reports from IV clinics are uncontrolled and rely on testimonials.

Why an honest reading is cautious

• Post-viral fatigue often improves over months regardless of treatment, which makes uncontrolled reports misleading
• Long COVID is not one condition; fatigue can stem from deconditioning, autonomic problems, poor sleep, mood, inflammation, lung or heart involvement
• Placebo effects on fatigue are substantial
• Studies have been small and short
• The NIH RECOVER program is running trials of possible treatments, a sign that none is established yet

Post-exertional malaise changes the plan

Some people with long COVID develop post-exertional malaise, where symptoms crash a day or two after physical or mental effort. This is a hallmark of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The CDC notes there is no cure or approved treatment for ME/CFS, that symptoms can worsen after activity, and that learning new ways to manage activity can help.

If you have post-exertional malaise, pushing through, including aggressive exercise programs, can make things worse. That is one reason a proper evaluation matters before trying any new treatment.

What should be checked first

• A full history of your infection, symptoms and how they respond to exertion
• Basic labs: blood count, iron studies, thyroid, B12, vitamin D, kidney and liver function, blood sugar
• Heart and lung symptoms such as chest pain, palpitations or breathlessness, which need in-person assessment
• Dizziness or a racing heart on standing, which may point to an autonomic problem such as POTS
• Sleep quality and possible sleep apnea
• Mood, which commonly shifts after a long illness and deserves its own care
• Medicines that cause fatigue

Day-to-day strategies that help many people

While research continues, several practical approaches help many people with post-viral fatigue. Pacing, which means planning activity in small amounts and resting before you are depleted, can reduce crashes. A regular sleep schedule, gentle hydration and salt strategies for dizziness when a clinician advises them, and support for mood and stress all have a role. Returning to exercise is usually done gradually and guided by symptoms, especially if post-exertional malaise is present. Keeping a simple diary of activity and symptoms helps you and your clinician spot patterns.

If you still want to try NAD+

If serious causes have been ruled out and you understand the evidence, a time-limited trial can be reasonable for some people. Agree on a starting point, a way to measure change, such as a simple daily energy and symptom log, and a review date with your clinician. Pace yourself during the trial so that a good day does not trigger a crash.

If nothing has clearly changed by the review point, stopping is a valid outcome. Side effects of NAD+ injections are usually mild, such as site redness, flushing and nausea, but long-term safety data do not exist.

Bring your symptom diary and any test results to the visit so your care team can see the whole picture.

Getting the right care

HealifyMD does not diagnose or manage long COVID. If you have persistent symptoms after an infection, your primary care clinician or a post-COVID clinic should lead your evaluation, and a HealifyMD clinician can coordinate around that. HealifyMD NAD+ injections are compounded by a licensed U.S. pharmacy; compounded drugs are not FDA-approved, and the FDA does not verify their safety, effectiveness or quality. The price is from $199/month, confirmed at your eligibility review, with labs priced separately.