If you’re taking a GLP-1 medication, you may have heard your doctor mention NAD+. But even if you’re not on a GLP-1,  NAD+ is worth knowing about.  

What is NAD+?  

NAD+ (nicotinamide adenine dinucleotide) is a molecule found in every cell of your body. It helps convert food into  energy, supports DNA repair to reduce cellular aging,  improves muscle and brain function, and regulates  inflammation. It’s especially important for mitochondria, the energy powerhouse of the cell.  

The problem? NAD+ levels decline naturally with age,  dropping roughly 50% between your 20s and 50s. They also fall with obesity, poor sleep, alcohol use, and metabolic dysfunction. And when NAD+ drops, you feel it: fatigue,  slower metabolism, brain fog, and cellular aging that underlies  conditions like cardiovascular disease, diabetes, and cognitive  decline.  

So it’s no wonder that increasing NAD+ has become a focus of anti-aging clinics and longevity researchers. It’s more than just an anti-wrinkle cream for your cells. Restoring optimal  NAD+ is a potential fountain of youth.  

Why does it matter if you’re on a GLP-1? 

GLP-1 medications are remarkably effective for weight loss,  but fatigue and brain fog are common complaints. Here’s why  NAD+ may help:  

• People with metabolic dysfunction or obesity tend to  start with lower NAD+ levels  
• Significant calorie restriction (common on GLP-1s) can  deplete NAD+ further, especially if you are not getting  enough nutrients (vitamin B3 is the direct precursor of  NAD+)  
• Rapid weight loss on GLP-1 medication is often up to  50% lean muscle. Muscle loss reduces both the number  and efficiency of mitochondria, which is where NAD+ does  most of its work  

This is why many GLP-1 prescribers now recommend NAD+  support alongside the medication.  

Do you need it even if you aren’t on a GLP-1?  

Possibly. If you are 25 and in good health, your NAD+ levels are probably fine and supplementing won’t make much difference. If you’re over 45, dealing with fatigue, brain fog, insulin resistance, high blood pressure, chronic inflammation, poor sleep, or regular alcohol use, your  NAD+ levels are likely lower than optimal. Viral infections  like COVID also appear to deplete NAD+ significantly (NAD+  is now being studied as a potential Long COVID treatment).  So anyone with a history of viral infections like COVID or  Epstein Barr may also benefit, especially if energy levels have not completely recovered. 

OK, I want to increase my NAD+ levels! How do I do it?  

You can’t just take an NAD+ pill. It’s too large to enter cells directly and gets broken down in the gut before it can do much. Instead, the more effective route is to take NAD+  precursors. These are smaller molecules that your cells  absorb easily and convert into NAD+:  

• NMN supplements (nicotinamide mononucleotide): At  least 500 mg daily  
• NR supplements (nicotinamide riboside): At least 800  mg daily  
• Exercise and fasting: Both naturally shift cellular energy  balance in ways that signal your body to produce more  NAD+  

Many clinics also offer NAD+ injections or IV infusions, which bypass digestion entirely. However, the molecule is still too large to enter cells easily so your body has to break it down,  absorb it, and reassemble it. The research on oral NMN and  NR is actually quite robust. These supplements have been  shown to meaningfully raise NAD+ levels in blood and  muscle, at a fraction of the cost of injections.  

Who should be cautious about NAD+ supplementation?  

NAD+ supplements are generally safe and well-tolerated.  However: 

• Active cancer or chemotherapy: NAD+ supports cell  survival and DNA repair, but this can also happen inside  cancer cells. Talk to your oncologist before supplementing.  
• MTHFR variants: NAD+ production depends on healthy methylation pathways. You may need additional methyl donors (active B vitamins, TMG) alongside it.  
• Active liver disease or flaring autoimmune conditions:  Reach out before starting.  

The Bottom Line  

If you’re experiencing fatigue on a GLP-1, NAD+ support is worth considering. And if you’re not on a GLP-1 but dealing with fatigue, cognitive issues, metabolic dysfunction, or are simply over 45, the same applies.  

Oral NMN or NR supplements are a practical, affordable starting point. If you’d like to test your NAD+ levels first,  specialty fingerstick testing is available (around $100). Just ask, and I can order it for you.  

Feel free to reply to this email if you have specific questions or concerns you want to discuss.  

Wishing you health and happiness!  

Dr. G  

Want to try a supplement proven to increase NAD levels?  Click here for my favorites!