NAD+, B12 and glutathione injections: an honest guide

NAD+ injections versus IV infusions

NAD+ can be given as a slow intravenous infusion over hours or as a smaller injection under the skin. Injections are quicker and easier to do at home but deliver smaller amounts at a time. Neither route has been shown in good-quality trials to improve energy, cognition or aging outcomes. The NAD+ injection prescribed through HealifyMD is compounded, so it is not FDA-approved and has not been reviewed by the FDA for safety or effectiveness.

People sometimes report feeling energized after an infusion. That experience is real to them, but without controlled studies it is hard to separate the effect of NAD+ from expectation, rest, hydration and the attention of the visit.

Side effects of NAD+ and when to stop

Common reactions include flushing, nausea, stomach cramping, headache, a feeling of chest tightness or pressure and tenderness at the injection site. With infusions, these often ease when the rate is slowed. Stop and seek urgent care for chest pain that does not settle, trouble breathing, swelling of the face or throat or fainting.

NAD+ is not a stimulant, so it should not cause the jittery feeling of caffeine. If you are pregnant, breastfeeding or being treated for cancer, discuss it with your clinician and oncologist first, because research on NAD+ in those settings is limited.

Oral precursors: niacin, nicotinamide, NR and NMN

Your body makes NAD+ from forms of vitamin B3, and the NIH notes that more than 400 enzymes depend on it. Nicotinic acid can cause flushing at doses as low as 30 to 50 mg; nicotinamide does not flush but can cause problems at very high doses. Nicotinamide riboside (NR) and NMN are marketed as NAD+ boosters. NR is sold as a supplement, while the FDA concluded in 2022 that NMN cannot be legally sold as a dietary supplement, leaving its status contested. Many so-called oral NAD+ products contain precursors rather than NAD+ itself.

Vitamin B12: who really benefits

B12 deficiency is more common than many people think, especially after 45. The NIH Office of Dietary Supplements lists older adults, people with pernicious anemia, long-term metformin users, people taking acid-reducing drugs such as proton pump inhibitors, people who have had stomach or weight-loss surgery and vegans as higher-risk groups. Deficiency can cause fatigue, anemia, numbness or tingling and memory problems, and nerve damage can occur even when the blood count looks normal.

Injections bypass absorption problems, which is why they are standard for severe deficiency or pernicious anemia. However, a Cochrane review found that high-dose oral B12 normalized blood levels about as well as injections in the studies it examined. If your B12 is already adequate, extra B12 is unlikely to boost energy.

Methylcobalamin, cyanocobalamin and hydroxocobalamin

These are different forms of B12. Cyanocobalamin is stable and widely studied; the cyanide it contains is tiny and is not considered harmful for most people. Methylcobalamin and hydroxocobalamin are also used. For most people, the form matters less than getting enough of it absorbed, and claims that one form is essential for people with MTHFR variants are not well supported.

Glutathione: big claims, thin evidence

Glutathione is an antioxidant your cells make from amino acids. It is marketed for detox, liver health, skin brightening and energy, but human evidence for those uses is limited. Oral glutathione is partly broken down in digestion, which is why injections and liposomal forms are promoted; NAC, a precursor, is another route your body uses to make it. Injectable glutathione prescribed through HealifyMD is compounded and not FDA-approved. People with sulfite sensitivity or asthma should mention it before starting, and skin lightening is not a use we support.

Before you start any wellness injection

Ask what problem the injection is meant to solve and how you will know if it worked. If the goal is more energy, a baseline lab panel that checks iron, B12, thyroid function and blood sugar often reveals a treatable cause that an injection would only mask. Tell your clinician about every supplement you take, and report any injection-site redness, swelling or unusual symptoms promptly.