NAD+ Supplements vs Injections: What the Evidence Compares

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Short answer: The oral “NAD supplements” tested in the human trials cited here are precursors, nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), which the body uses to make NAD+. In those trials, oral NR and NMN raised NAD+ in blood or blood cells, while a 2026 systematic review described their effects on health outcomes as “heterogeneous and often null or endpoint-specific” (Gallagher and Emmanuel, 2026). No published study has compared oral NAD+ supplements with NAD+ injections, so the evidence cannot say which one raises NAD+ more or does more.

Below is what each cited study measured, by form and route, and where the comparisons people search for simply do not exist yet.

What is in an “NAD supplement”?

NAD+ (nicotinamide adenine dinucleotide, listed in PubChem as nadide) is a coenzyme found in cells (PubChem). NR and NMN are precursors, the raw materials for making it. The authors of one NMN trial describe NMN availability as “a rate-limiting factor in mammalian NAD+ biosynthesis” (Yoshino et al., 2021).

In the trials cited here, “NAD supplement” meant oral NR or NMN, while the IV studies delivered NAD+ itself. Those are different molecules given by different routes. For the chemistry behind the names, see our explainer on whether NAD+ is a peptide, and for the precursor trials in more depth, our NMN vs NAD+ comparison.

What did oral NR and NMN studies measure?

Each study below used a different dose, a different group of people and a different place to measure NAD+, so the rows cannot be ranked against each other.

Study	What was given	Who and how long	Where NAD+ was measured	What was reported
Yoshino 2021	Oral NMN 250 mg/day vs placebo	25 postmenopausal women with prediabetes, 10 weeks	Blood cells (PBMCs) and thigh muscle	Blood-cell NAD+ increased; muscle NAD+ did not change
Igarashi 2022	Oral NMN 250 mg/day vs placebo	Healthy older men, 6 or 12 weeks	Whole blood	NAD+ and NAD+ metabolites increased significantly
Martens 2018	Oral NR 500 mg twice daily vs placebo (crossover)	30 healthy middle-aged and older adults, two 6-week periods	Blood cells (PBMCs)	NAD+ about 60% higher than placebo
Trammell 2016	Single oral NR doses of 100, 300 and 1,000 mg	One person in a pilot, then a clinical trial	Blood	Dose-dependent increases in the blood NAD+ metabolome; up to 2.7-fold NAD+ in the single person

Some details matter when reading these results. In the Yoshino trial, the authors reported that “NAD+ and nicotinamide content did not change” in muscle in either group, even though blood-cell NAD+ rose (Yoshino et al., 2021). Three authors of the Igarashi trial were employees of Mitsubishi Corporation Life Sciences (Igarashi et al., 2022). The PubMed record for Trammell 2016 lists ChromaDex, an NR supplier, as sponsor of the clinical study (Trammell et al., 2016).

What did IV and injected NAD+ studies measure?

Two human studies cited here gave NAD+ itself, both by IV, and neither measured the same things as the oral trials.

Grant 2019: a 6-hour IV infusion

In this small pilot, NAD+ was infused at 3 μmol per minute for 6 hours. Plasma NAD+ and its metabolites did not change until after 2 hours, and the authors wrote that NAD+ “is rapidly and completely removed from the plasma for at least the first 2 h.” NAD+ and methylnicotinamide were found in urine at 6 hours. The PubMed record lists NAD+ Research Inc. and Springfield Wellness Center among the author affiliations (Grant et al., 2019).

Reyna 2026: IV NAD+ vs IV NR in a commercial clinic

This retrospective review of medical records looked at clients who received four consecutive days of 500 mg IV NAD+ (6 clients) or 500 mg IV NR (8 clients), with 30 days of follow-up. All 6 NAD+ clients reported moderate to severe gastrointestinal symptoms, increased heart rate and chest pressure during infusions, and NAD+ infusions averaged 97 minutes vs 37 minutes for NR. The authors reported that all symptoms resolved when the infusion ended, and they called the metabolic findings “variable.” The study tracked symptoms, blood pressure, heart rate and routine blood tests. Whole-blood NAD+ was sampled with dried blood spots, but the authors wrote that the sampling was not sufficient to detect changes. The authors were employed by Restore Hyperwellness, the commercial IV provider, which also funded the study (Reyna et al., 2026).

Subcutaneous and intramuscular NAD+

None of the human studies cited on this page tested NAD+ injected under the skin or into muscle. The 2026 systematic review of 33 human studies found no eligible outcome trials of IV or intramuscular NAD+ for anti-aging or wellness (Gallagher and Emmanuel, 2026). Our page on what has been published about NAD+ injections covers this route in more detail, and clinic IV pricing is on our NAD IV therapy cost page.

Has any study compared NAD+ supplements with injections?

No. No published study has given one group an oral NAD+ supplement and another group an NAD+ injection and compared the results. The closest is Reyna 2026, which compared IV NAD+ with IV NR, both given by vein, and focused on tolerability (Reyna et al., 2026). Without such a trial, a claim that one form “absorbs better” or “works better” has no head-to-head data behind it.

This table summarizes what the cited sources contain for each form:

Form	Human NAD+ level data in cited sources	Human outcome data in cited sources	Compared head to head with another form?
Oral NR or NMN (precursors)	Yes: blood, blood cells, whole blood (Yoshino, Igarashi, Martens, Trammell)	Yes, mixed: “often null or endpoint-specific” (Gallagher 2026)	No NR vs NMN trial cited; no oral vs injection trial
Oral liposomal NAD+	None published (see our liposomal NAD+ review)	None published	No
IV NAD+	Yes: plasma and urine during one 6-hour infusion (Grant 2019)	Tolerability in 6 clients (Reyna 2026); no eligible outcome trials (Gallagher 2026)	IV NAD+ vs IV NR, tolerability only (Reyna 2026)
Subcutaneous or intramuscular NAD+	None in cited sources	No eligible IM outcome trials (Gallagher 2026)	No
Nasal NAD+	None in cited sources	None in cited sources	No

For a side-by-side of the prescription routes on practical points, see our NAD+ IV vs injection vs nasal spray guide.

Do NAD+ supplements change health outcomes?

Raising a blood marker and changing how a person feels or functions are different questions. The 2026 systematic review of 33 human intervention studies, published from January 2010 to October 2025, reported that oral NR and NMN “consistently demonstrated biochemical target engagement,” meaning NAD+-related markers went up. It described effects on functional, metabolic, vascular and other outcomes as “heterogeneous and often null or endpoint-specific,” and concluded that clinical effectiveness for anti-aging or wellness outcomes “remains inconclusive” (Gallagher and Emmanuel, 2026).

A 2025 meta-analysis of randomized trials in adults with a mean age over 60 reported that NMN had no significant effect on skeletal muscle index, grip strength, gait speed or chair-stand time. Its authors concluded that “current evidence does not support NMN and NR supplementation for preserving muscle mass and function” in that age group (Prokopidis et al., 2025).

Is there a best NAD+ supplement?

The cited evidence does not support naming one. Two points from the sources on this page:

• No head-to-head trial. The NR and NMN trials above tested each precursor separately, in different people, at different doses. None compared NR with NMN directly, and the 2026 review grouped them together (Gallagher and Emmanuel, 2026).
• No human absorption data for liposomal NAD+. The only peer-reviewed liposomal NAD+ study cited here was lab work in human cells and skin samples, not people (Ministrini et al., 2025).

If you are weighing a supplement, a licensed provider can review it against your health history and any medicines you take.

How are NAD+ supplements and injections regulated?

They sit in different categories. The NR and NMN products used in the oral trials above are taken by mouth as supplements, and the trials studied them as supplementation (Martens et al., 2018). NAD+ injections and nasal sprays offered through PrescribedRX are compounded prescription products, so a licensed provider decides whether one is appropriate for you.

	Oral NR or NMN supplement	NAD+ injection or nasal spray
Category	Supplement	Compounded prescription product
Prescription needed?	No	Yes

NAD+ offered through PrescribedRX

PrescribedRX does not sell NR, NMN or oral NAD+ supplements. Two NAD+ products are offered through PrescribedRX, both compounded. Compounded medications are prepared by licensed pharmacies and are not FDA-approved. The oral precursor and IV studies above did not test these products, so their results do not apply to them. Prices as displayed on the product pages in October 2026:

Product	Form as listed	3 month plan	Monthly plan
NAD+ Injection 200mg/mL 6ml (compounded)	Subcutaneous injection · Provider-dosed	3 month plan $412 · $137/mo · Billed every 3 months. Cancel anytime.	Monthly plan $169 a month
NAD+ Nasal Spray 200mg/mL 6ml (compounded)	Nasal spray · No needles	3 month plan $412 · $137/mo · Billed every 3 months. Cancel anytime.	Monthly plan $169 a month

A licensed provider decides whether it is appropriate for you, and your provider sets the dose. Plans are self-pay and availability varies by state. Every plan is listed on our pricing page.

When should you talk to a doctor?

Talk to a licensed provider before starting NR, NMN or NAD+ in any form, especially if you have a health condition or take other medicines. The cited studies reported these reactions:

• Oral NR: in a crossover trial, 7 of 30 participants reported mild adverse events across both periods. Those during the NR period included nausea, flushing, leg cramps and increased bruising; those during placebo included headache, skin rash, flushing, fainting and drowsiness (Martens et al., 2018).
• IV NAD+: all 6 clients in one retrospective review reported moderate to severe gastrointestinal symptoms, increased heart rate and chest pressure during infusions (Reyna et al., 2026).

Our page on NAD+ side effects summarizes what has been reported for prescription NAD+. In an emergency, call 911.

Frequently asked questions

Do NAD supplements work?

It depends on what is measured. Oral NR and NMN raised NAD+ in blood or blood cells in the trials cited here. A 2026 review of 33 human studies found effects on health outcomes “heterogeneous and often null or endpoint-specific” and called clinical effectiveness “inconclusive.” One NMN trial found no change in muscle NAD+.

Are NAD injections better than supplements?

No published study has compared them. Oral precursor trials measured NAD+ in blood; the IV studies measured plasma levels during one infusion or tolerability in a small group. None of the cited human studies tested subcutaneous NAD+. Without a head-to-head trial, the evidence cannot say which is better.

See whether NAD+ is available to you

If you want a licensed provider to review whether NAD+ injection or nasal spray is appropriate for you, start with the eligibility check. Both are compounded, and the price is shown before you pay: “3 month plan $412 · $137/mo · Billed every 3 months. Cancel anytime.” You can also browse all longevity treatments.

Sources

1. National Library of Medicine. PubChem Compound Summary: Nadide (NAD+), CID 5892. PubChem. Accessed Oct 2026.
2. Yoshino M, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science. 2021;372:1224-1229. PubMed. Accessed Oct 2026.
3. Igarashi M, et al. Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men. NPJ Aging. 2022;8:5. PubMed. Accessed Oct 2026.
4. Martens CR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun. 2018;9:1286. PubMed. Accessed Oct 2026.
5. Trammell SA, et al. Nicotinamide riboside is uniquely and orally bioavailable in mice and humans. Nat Commun. 2016;7:12948. PubMed. Accessed Oct 2026.
6. Grant R, et al. A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD. Front Aging Neurosci. 2019;11:257. PubMed. Accessed Oct 2026.
7. Reyna K, et al. Intravenous infusion of nicotinamide adenine dinucleotide (NAD+) versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting. Front Aging. 2026;7. Frontiers. Accessed Oct 2026.
8. Gallagher C, Emmanuel OO. NAD+ supplementation for anti-aging and wellness: a PRISMA-guided systematic review of preclinical and clinical evidence. Ageing Res Rev. 2026;116:103057. PubMed. Accessed Oct 2026.
9. Prokopidis K, et al. The effect of nicotinamide mononucleotide and riboside on skeletal muscle mass and function: a systematic review and meta-analysis. J Cachexia Sarcopenia Muscle. 2025;16(3):e13799. PubMed. Accessed Oct 2026.
10. Ministrini S, et al. A Liposomal Formulation Enhances the Anti-Senescence Properties of Nicotinamide Adenine-Dinucleotide (NAD+) in Endothelial Cells and Keratinocytes. Curr Issues Mol Biol. 2025;47(9):722. PubMed. Accessed Oct 2026.

This article is for general information. It is not medical advice and it is not a recommendation for any particular treatment. Whether a treatment is appropriate for you is a decision for a licensed clinician who has reviewed your health history and current medications.