NAD+ common uses, half-life, side effects and more

NAD+ is a coenzyme every cell uses to turn food into energy and to run repair. It is not a peptide. Clinics infuse it into a vein and compounding pharmacies sell it as an injection for energy, mental clarity, recovery, and longevity goals. Addiction clinics have used it for withdrawal since the 1960s. No regulator anywhere has approved it for any use. Lawful supply in the United States runs through a compounding pharmacy on a prescription. The same material is also sold online without one. The FDA has tied food-grade NAD+ to contaminated injections that sent people to an emergency room.

• Energy and mental clarity
• Recovery after exertion
• Longevity and healthy-aging protocols
• Addiction and withdrawal programs
• Chronic fatigue and long COVID protocols

Daily courses by vein and one to three times weekly under the skin

Clinic infusions commonly run 500 to 1000 mg into a vein over one to six hours. The one controlled study gave 750 mg over six hours. Addiction programs have run 500 to 1000 mg a day for up to ten days. No clinical trial has established a dose for any other route. Compounding pharmacies suggest starting at 20 to 50 mg under the skin one to three times a week and rising toward 100 mg. They disagree with each other on the starting amount, the frequency, and the strength of the solution. A weekly ceiling of 300 mg circulates on those same pages with nothing behind it. Intramuscular figures are the same numbers on a longer needle. Nasal sprays and 200 mg sublingual tablets are sold with nothing established behind either.

• A dose written in syringe units means nothing without the strength on the label because compounded solutions run from 100 to 500 mg per mL
• The same units-based instruction against a stronger vial delivers several times the intended dose
• Pharmacies give one combined instruction for under the skin and into muscle rather than a separate dose per route
• Clinics stop infusion symptoms by slowing the drip and nobody has tested whether starting slower prevents them
• Gray-market powder comes as 500 mg and 1000 mg vials with no standard mixing volume

Nobody has measured how long injected NAD+ lasts in a person. Two human infusion studies exist and neither reports a half-life. The numbers that circulate run from five minutes to five hours and trace to a mouse liver measurement, to a citation pointing at a head and neck cancer trial, or to nothing at all.

NAD+ is unstable enough that the FDA advisory committee reviewing it named storage stability as a reason to keep it off the compounding list. A ready-made solution carries a pharmacy beyond-use date that depends on the formulation rather than a general rule. The label governs. Powder sold for mixing carries no such date at all.

• Cramping, diarrhea, nausea, vomiting, racing heart, throat pain, and chest pressure during an infusion
• Every one of six people in a clinic study reported moderate to severe symptoms during the drip
• Symptoms stop when the infusion stops
• Injection site pain and soreness are the most consistent complaint across the injected routes
• Severe chills, shaking, vomiting, and fatigue were reported to the FDA after contaminated injections

NAD+ carries electrons between the reactions that release energy from food. That job cycles it between two forms and consumes none of it. Three enzyme families do consume it. Sirtuins, PARP enzymes, and CD38 each cut the molecule apart to do their work and release nicotinamide. The cell has to rebuild that back into NAD+ from scratch. Injected NAD+ mostly does not reach the inside of a cell intact. Cells have no general transporter for a molecule of that size and charge. Enzymes on the outer cell surface break it down first. The pieces are carried in and reassembled inside. The one human infusion study saw that pattern. Its breakdown products rose alongside the NAD+ itself.

Two small studies have infused NAD+ into healthy people and businesses that sell it funded both. One gave 750 mg over six hours to eight men and reported no side effects. It never asked them how they felt. The other recorded moderate to severe reactions in all six people who received it. No controlled trial shows that injected NAD+ improves fatigue, cognition, body composition, addiction outcomes, or lifespan. Doctors have infused it for withdrawal since 1961 and that record is still case reports and uncontrolled series. The premise behind most of the marketing is that NAD+ falls with age. A 2026 study measured whole blood across seven groups of people and found no change with age. That result concerns blood rather than tissue. Reports of decline inside tissue still stand. Human evidence for swallowed nicotinamide riboside and nicotinamide mononucleotide is stronger and says nothing about an injection.

• Injectable NAD+ is not approved anywhere and a compounded prescription reflects a decision not to prosecute rather than a safety finding
• FDA has tied food-grade raw material to contaminated injections and one recalled lot sent three people to an emergency room
• Nobody has studied it in pregnancy, breastfeeding, kidney disease, or liver disease
• Active cancer and PARP inhibitor treatment warrant an oncologist's input because tumors lean on the same salvage pathway
• An intravenous drip over 100 mL in twelve hours is a prohibited method in sport at all times and that rule does not reach injections under the skin or into muscle
• No anti-doping body has ruled on whether the catch-all clause covering unapproved substances reaches injectable NAD+