NAD+ related supplements are available in many forms, including oral capsules, tablets, powders, sublingual products, liposomal preparations, transdermal patches, injections and intravenous infusions. These forms are often advertised as different ways to improve the delivery or absorption of NAD+. However, the quantity and quality of human trial data vary significantly between the individual methods.
The strongest clinical evidence currently concerns oral capsules and tablets containing NAD+ precursors, such as NR and NMN. Other formats, including liposomal products, sublingual tablets, transdermal patches, injections, and intravenous NAD+, have a significantly smaller or less well-controlled evidence base.
In this guide, we compare the main forms of NAD+ supplements, explain what they typically contain, discuss the data regarding claimed absorption, and point out areas where scientific support still remains limited.
NAD+ supplement forms at a glance
It should not be assumed that different forms of NAD+ supplements provide the same absorption, biological exposure, safety, or clinical effects. The strongest evidence currently concerns oral NAD+ precursors, whilst several newer delivery methods rely primarily on theoretical absorption benefits or limited early-phase research.
| Shape | What does it usually contain | Declared bioavailability benefit | Typical range investigated | Market availability | Evidence from randomised human studies |
|---|---|---|---|---|---|
| Oral capsules/tablets | NAD+ precursors, such as NR, NMN, niacin or nicotinamide | Standard gastrointestinal absorption | Approximately 100–2000 mg/day depending on the compound [1–3] | Very wide | Strongest evidence base, multiple placebo-controlled randomised trials [1–4] |
| Powder | The same NAD+ precursors as in the capsules | It is usually assumed that the effect is similar to swallowing a capsule | Individually measured quantity | Wide | The evidence relates to the compound itself; there are no studies comparing the powder with the capsules |
| Sublingual tablets/lozenges | NAD+ precursors or, less commonly, NAD+ | Declared partial bypass of the digestive tract | Lack of standardisation, depending on the product | Available online and in specialist shops | There are no direct studies comparing sublingual administration with standard oral administration |
| Liposomal | NAD+ or its precursors encapsulated in lipid carriers | Protection of the compound and possible increased absorption or cellular transport | Depending on the product | Available, usually more expensive | Limited data; one human preprint study showed an increase in intracellular NAD+ [5], and there are also cellular data [6] |
| Transdermal patches | NAD+, sometimes with another compound, e.g. low-dose naltrexone | Gradual absorption through the skin, sometimes with iontophoresis | Depending on the product | Limited availability | One small open-label study on post-COVID-19 fatigue, with the simultaneous use of another medicinal product [7] |
| Intramuscular/subcutaneous injections | NAD+ | Bypass of the gastrointestinal tract | Clinic-determined | Available in selected clinics and telemedicine services | Very limited controlled data on clinical outcomes [8] |
| Intravenous infusion | NAD+ | Direct administration into the bloodstream | Determined by the clinic, often during long infusions | Common in IV and med-spa clinics | A 2026 systematic review found no eligible controlled trials for wellness/anti-ageing; retrospective data indicated more gastrointestinal and cardiac symptoms than with IV NR [8,9] |
The most important thing is the distinction between the method of presentation and the quality of the evidence.
The product may look technologically more advanced, but it does not have to have stronger clinical support.
Oral capsules and tablets: what to expect?
Oral capsules and tablets are the most common form of NAD+-related products and currently have the strongest human research base.
In most cases, they do not contain intact NAD+.
Instead, they utilise precursors such as nicotinamide riboside, nicotinamide mononucleotide, niacin or nicotinamide. Once absorbed, these compounds enter the NAD+ biosynthesis pathways and are converted into NAD+ through normal cellular metabolism.
Most contemporary clinical trials concern NR and NMN.
Randomised placebo-controlled trials have evaluated oral NR in amounts reaching approximately 2000 mg daily, and NMN in amounts reaching approximately 900–2000 mg daily, depending on the trial design. [1–4]
In many of these studies, supplementation with oral precursors increased blood levels of NAD+ or concentrations of related metabolites.
This is the most repeatable result.
Studies also generally showed good short- and medium-term tolerability, over periods ranging from a few weeks to about a year, depending on the compound studied. [1–4]
However, this does not mean that boosting NAD+ guarantees an improvement in all potential health outcomes.
Results concerning metabolism, physical fitness, the cardiovascular system, cognitive function or other endpoints were more variable.
This matters when evaluating marketing messages.
The strongest evidence for oral NR and NMN relates to their effects on NAD+-related biomarkers. Data regarding broader clinical benefits depend to a greater extent on the population, dose, duration and specific endpoint.
Therefore, capsules and tablets currently have the best direct support from randomised human trials, but they should not be presented as proven treatments for ageing or diseases.
Sublingual and liposomal products: do they really improve absorption?
Sublingual and liposomal products are often advertised as methods improving absorption compared to standard capsules.
However, their assumptions are different.
Sublingual products utilise the oral mucosa, whereas liposomal preparations are designed to surround NAD+ or its precursors with lipid structures.
The level of evidence for both approaches is not the same.
Sublingual NAD+ and its precursors
Sublingual tablets and lozenges are meant to dissolve under the tongue.
The premise is that some of the compounds may be absorbed through the oral mucosa, potentially limiting gastrointestinal degradation or first-pass metabolism.
This is a well-established pharmacological concept.
However, this does not automatically mean that every substance will be absorbed more effectively via this route.
For NAD+ and its precursors, no controlled human study has been identified that directly compares sublingual administration with a standard oral capsule.
This means that claims regarding the higher bioavailability of sublingual NAD+ or NMN remain largely theoretical.
The sublingual form alone does not confirm greater systemic exposure, better cellular uptake, or a stronger biological effect.
Direct pharmacokinetic studies would be needed to demonstrate such an advantage.
Liposomal NAD+
Liposomal preparations utilise lipid structures surrounding the active ingredient.
Their purpose is usually to protect the compound from degradation and potentially increase absorption or cellular delivery.
This form has slightly more direct data than sublingual preparations.
In one controlled human trial, oral liposomal NAD+ increased intracellular NAD+ levels by approximately 53% compared with placebo after five days in healthy individuals aged 45–75. [5]
The result is interesting because it indicates the impact of a specific formulation on an intracellular biomarker.
However, at the time discussed here, the study had not undergone a full scientific peer review.
This limits the certainty of the conclusions.
The same study also assessed well-being and metrics from wearable devices.
After correction for multiple comparisons, none of these additional clinical or functional outcomes remained statistically significant. [5]
That is an important distinction.
An increase in intracellular NAD+ signifies targeting a biomarker, but is not automatically proof of an improvement in health or function.
Additional laboratory studies analysed liposomal NAD+ in endothelial cells and keratinocytes.
Stronger effects were observed in some markers related to cellular ageing than with non-liposomal NAD+. [6]
However, these are data from cell cultures, not confirmation of a clinical effect in humans.
Generally speaking, liposomal NAD+ currently has slightly more direct data than sublingual products.
However, both forms are much less studied in humans than standard oral NR and NMN.
NAD+ transdermal patches
NAD+ transdermal patches are a newer and less researched delivery method.
Some rely on passive penetration through the skin.
Others utilise iontophoresis, which is a mild electrical current intended to increase the transport of the compound through the skin.
The most significant data in humans come from a small open-label study involving 36 people with persistent post-COVID-19 fatigue. [7]
Participants received low-dose naltrexone orally and NAD+ via iontophoresis patches for 12 weeks.
Researchers described the improvement in quality of life and fatigue severity compared to baseline values.
The combined intervention was also evaluated as generally well tolerated.
About one quarter of participants experienced mild and short-lived skin irritation associated with the patches. [7]
However, the research project has a significant limitation.
Participants used naltrexone and NAD+ simultaneously.
There was no group receiving NAD+ patches alone.
There was also no placebo.
It is therefore impossible to determine what proportion of the observed improvement was due to NAD+, naltrexone, the combination of both interventions, natural recovery, expectancy effects or other factors.
The authors themselves pointed out this limitation and emphasised the need for larger controlled studies.
Currently, NAD+ patches are best described as a biologically plausible delivery method with very limited and partly confounded clinical data.
Available research does not prove that transdermal NAD+ alone improves post-COVID fatigue or other conditions.
NAD+ injections and intravenous infusions
NAD+ in the form of injections and intravenous infusions is widely offered by wellness clinics, IV therapy centres, med-spas, and some telehealth and compounding services.
These forms are often promoted as better because they bypass the digestive tract and deliver NAD+ more directly.
This assumption is intuitive.
The evidence base is considerably weaker.
NAD+ injections
Intramuscular or subcutaneous administration bypasses the digestive tract.
This can affect systemic exposure compared to oral supplementation.
However, direct human data regarding clinical outcomes following injectable NAD+ remain very limited. [8]
Bypassing the digestive breakdown does not automatically mean a stronger biological effect.
Pharmacokinetics, cellular uptake, tissue distribution, tolerance and clinical effects still need to be measured directly.
Intravenous NAD+
Intravenous NAD+ goes directly into the bloodstream.
It is frequently promoted in the context of energy, recovery, cognitive function, detoxification, healthy ageing and general wellness.
Despite wide commercial availability, controlled clinical data remain surprisingly limited.
A 2026 systematic review found no eligible controlled human studies evaluating intravenous or intramuscular NAD+ in the context of anti-ageing or wellness. [8]
This is an important distinction between the availability of a product and its scientific validation.
Intravenous NAD+ may be widely offered without having the same basis in randomised trials as oral NR or NMN.
In a separate retrospective observational study, intravenous NAD+ was compared with intravenous nicotinamide riboside. [9]
In the NAD+ group, gastrointestinal and cardiac symptoms were reported more frequently.
Because the study was retrospective rather than randomised, it does not allow for definitive conclusions regarding comparative safety.
It points, however, to specific questions regarding tolerance that require further controlled studies.
Therefore, the available evidence does not show that intravenous or injection NAD+ is ineffective.
They show rather that claims of its superior efficacy currently go beyond available controlled clinical data.
This is a situation that is significantly different from oral NAD+ precursors.
NAD+ powder: is it different from capsules?
NAD+ precursor powders typically contain the same compounds as capsules, especially NMN or NR.
The main difference is in the physical form.
The powder allows you to measure out the quantity yourself, instead of using a fixed dose in a capsule.
This can provide greater flexibility.
It can also affect the convenience, storage method, and the product's contact with heat, light, air or moisture.
However, no controlled human study has been identified showing that NMN or NR powder has a higher bioavailability than the same compound in a capsule.
Clinical evidence therefore concerns the active ingredient itself, not the powder form.
This is relevant when interpreting claims that powder is inherently absorbed faster or more effectively.
Such statements require a direct pharmacokinetic comparison.
Without such data, the powder should be regarded primarily as an alternative physical form of the NAD+ precursor rather than a confirmed method with higher bioavailability.
How to choose the form of NAD+ depending on your goal?
The quality of the evidence is very unevenly distributed among the individual forms.
Therefore, choosing on the basis of which method looks more advanced, direct, or technologically innovative can lead to erroneous conclusions.
If the priority is the strongest human research base
Oral capsules and tablets containing well-researched precursors, such as NR or NMN, currently have the strongest research support.
Many randomised placebo-controlled trials have demonstrated that these compounds can increase NAD+-related biomarkers in humans. [1–4]
This does not mean that all the longevity, metabolic or cognitive benefits attributed to them have been proven.
It merely means that their impact on NAD+ biomarkers is much better documented than in the case of most alternative methods.
If the priority is a potential improvement in absorption
Sublingual, liposomal and transdermal products are often chosen precisely because of their claimed better absorption.
However, the evidence is very different.
Liposomal NAD+ has early human data indicating an increase in intracellular NAD+, but the key study was still a preprint and, after correction for multiple comparisons, did not show significant benefits in additional clinical endpoints. [5]
Transdermal patches have one small open-label study in which NAD+ was used alongside a low dose of naltrexone, making it impossible to determine the independent effect of the patches. [7]
In the case of sublingual preparations, on the other hand, there are no direct studies in humans demonstrating superior absorption over standard oral forms.
In many of these cases, therefore, the theoretical rationale is stronger than the clinical evidence.
If the priority is direct administration at the clinic
Injections and intravenous drips bypass the digestive tract.
This may give the impression of a more direct method.
However, it does not mean better clinical evidence.
A 2026 systematic review found no eligible controlled trials regarding IV or IM NAD+ in the areas of anti-ageing and wellness. [8]
Retrospective data also point to questions regarding gastrointestinal and cardiac tolerability with IV NAD+ compared to IV NR. [9]
These methods therefore have a much weaker base of controlled human studies than their popularity would suggest.
Regardless of the form, it is the tangible relationship that counts
The method of serving is just one element.
The exact active ingredient is just as important.
An NMN capsule, an NR tablet, liposomal NAD+ and an intravenous NAD+ infusion are not equivalent interventions just because they all fall under the broad category of „NAD+ supplementation”.
What matters are the dose, chemical identity, route of administration, formulation, pharmacokinetics and study population.
Therefore, comparing a specific compound and its conditions of use with those used in clinical trials is more valuable than being guided by marketing terms such as „maximum bioavailability”, „direct delivery to cells” or „advanced NAD+ technology”.
Comparison of NAD+ supplement forms
| Feature | Oral NR/NMN | Powder | Sublingual | Liposomal | Transdermal patches | NAD+ injections | IV NAD+ |
|---|---|---|---|---|---|---|---|
| Widely available | Yes | Yes | Yes | Yes | More restricted | Clinic-dependent | Yes, in clinics |
| Randomised human data | The strongest | They relate to the substance, not the form | Very limited | Early/limited | Very limited | Very limited | Very limited |
| Demonstrated increase in NAD+ biomarkers | Yes | Based on the data for the ingredient | Lack of a clear comparison | Early data suggests so [5] | It cannot be isolated | Limited | Limited |
| Direct absorption comparisons | Some pharmacokinetic data for precursors | No powder–capsule comparison | No direct comparisons | Limited | Limited | Limited | Limited |
| Clinical indication required | Not | Not | Not | Not | Not usually | Usually, yes | Yes |
| bypass the gastrointestinal tract | Not | Not | Partially — declared | It is supposed to improve delivery | Yes, through the skin | Yes | Yes |
| Proven clinical superiority | Not | Not | Not | Not | Not | Not | Not |
| Main constraint | Ambiguous functional results | Lack of form testing | No direct comparisons | Early-stage research | Small study with combination therapy | Few controlled studies | No eligible controlled wellness trials in the 2026 review. |
The most important distinction therefore concerns the well-studied oral precursors and newer or more invasive methods, for which the evidence base of controlled human trials is considerably smaller.
Frequently asked questions about NAD+ supplement forms
Which form of NAD+ supplement is the best researched?
Oral capsules and tablets containing NAD+ precursors, such as NR and NMN, have the strongest human research base.
Numerous randomised placebo-controlled trials have demonstrated that oral NR and NMN can increase blood NAD+ or related metabolite levels. [1–4]
This does not mean that they improve all possible health effects related to NAD+ biology.
Is liposomal NAD+ absorbed better?
Early data suggest that a specific liposomal formulation may increase intracellular NAD+ levels, but the main controlled human study discussed here was still a preprint and had not undergone full peer review. [5]
Following correction for multiple comparisons, no statistically significant improvements were demonstrated in the additional clinical and well-being outcomes either.
Higher clinical efficacy has therefore not been confirmed.
Is sublingual NAD+ better than capsules?
No controlled human study was identified that directly compared sublingual NAD+ or its precursors with standard oral capsules.
The sublingual route has a sound pharmacological rationale, but the bioavailability advantage specific to NAD+ remains unproven.
Do NAD+ patches work?
Data on humans are currently very limited.
One small open-label study showed an improvement in fatigue and quality of life when NAD+ patches were used together with low-dose naltrexone. [7]
Because there was no placebo group or NAD+-only group, the independent effect of the patches alone cannot be determined.
Is NAD+ powder better than capsules?
There is no strong evidence that powder gives a higher bioavailability than capsules containing the same active ingredient.
The main difference is greater flexibility in measuring out the quantity.
Are injectable NAD+ and oral precursors better?
This has not been demonstrated in controlled comparative studies in humans.
An injection bypasses the gastrointestinal tract, but the route of administration alone does not confirm higher clinical efficacy or better cellular exposure.
Is IV NAD+ more effective because it goes directly into the bloodstream?
Direct administration into the bloodstream confirms the route of administration, not the clinical outcome.
A 2026 systematic review found no eligible controlled human studies evaluating intravenous or intramuscular NAD+ for anti-ageing or wellness applications. [8]
Claims of greater effectiveness therefore remain insufficiently substantiated.
Which form of NAD+ has the most clinical evidence?
Oral NR and NMN currently have the largest number of randomised human trials.
Sublingual products, liposomal products, patches, injections and intravenous infusions have significantly smaller and less mature evidence bases.
Limitations of current evidence
The first major limitation is the large difference in data quality between the various delivery forms.
Oral NR and NMN have the strongest base of randomised human trials, but even in their case, results regarding anything more than an increase in NAD+ biomarkers remain inconclusive. [1–4]
The second limitation concerns liposomal NAD+.
The human study in question showed an increase in intracellular NAD+, but at the time of analysis it was available as a preprint rather than a completed peer-reviewed publication. Additional clinical results and wearable device data did not remain significant after correction for multiple comparisons. [5]
Even more difficult to interpret are the data concerning transdermal forms.
The pilot study was small, open-label and without a control group, and the NAD+ patches were used alongside low-dose oral naltrexone. Therefore, the effect of the transdermal NAD+ alone cannot be isolated. [7]
Another major gap is the lack of direct pharmacokinetic comparisons.
No human study has been identified that directly compares sublingual NAD+ with standard oral, capsule powder or several newer formulations with well-studied oral NR or NMN under equivalent conditions.
Finally, intravenous and injectable NAD+ remains widely advertised despite a very limited base of controlled clinical trials.
A 2026 systematic review found no eligible controlled human studies regarding intravenous or intramuscular NAD+ for anti-aging and wellness applications. [8]
It is therefore scientifically most justifiable to separate commercial availability from clinical validation.
The product may be widely sold, technologically advanced or administered in a clinic, and yet have no stronger evidentiary base than a simpler oral preparation.
Disclaimer
This article is for educational, scientific and informational purposes only. It does not constitute medical advice, a dosing or administration instruction, a therapeutic recommendation, product selection advice, or a recommendation for the use of NAD+, NMN, NR, liposomal preparations, transdermal patches, injectable NAD+, intravenous NAD+, or any other NAD+-related interventions.
Individual forms of NAD+ supplements have very different levels of evidence in humans. The results of studies on oral NR or NMN should not be automatically extrapolated to sublingual, liposomal, transdermal, injectable or intravenous formulations, and claimed superior absorption should not be treated as evidence of better clinical outcomes without direct comparative studies.
NAD+ and its precursors are not FDA- or EMA-approved treatments, preventatives, or cures for diseases. Regulatory status, formulation standards, and permitted uses may vary between countries and change over time.
References
[1] Yi, L., Maier, A. B., Tao, R., Lin, Z., Vaidya, A., Pendse, S., Thasma, S., Andhalkar, N., Avhad, G., & Kumbhar, V. (2022). The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: A randomised, multicentre, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. GeroScience, 45, 29–43. https://doi.org/10.1007/s11357-022-00705-1
[2] Pencina, K. M., Lavu, S., Dos Santos, M., Beleva, Y. M., Cheng, M., Livingston, D., & Bhasin, S. (2023). MIB-626, an oral formulation of a microcrystalline unique polymorph of β-nicotinamide mononucleotide, increases circulating nicotinamide adenine dinucleotide and its metabolome in middle-aged and older adults. The Journals of Gerontology: Series A, 78(1), 90–96. https://doi.org/10.1093/gerona/glac049
[3] Conze, D., Brenner, C., & Kruger, C. L. (2019). Safety and metabolism of long-term administration of NIAGEN (nicotinamide riboside chloride) in a randomised, double-blind, placebo-controlled clinical trial of healthy overweight adults. Scientific Reports, 9, 9772. https://doi.org/10.1038/s41598-019-46120-z
[4] Dellinger, R. W., Santos, S. R., Morris, M., Evans, M., Alminana, D., Guarente, L., & Marcotulli, E. (2017). Repeat dose NRPT (nicotinamide riboside and pterostilbene) increases NAD+ levels in humans safely and sustainably: A randomised, double-blind, placebo-controlled study. npj Aging and Mechanisms of Disease, 3, 17. https://doi.org/10.1038/s41514-017-0016-9
[5] Kornilov, S. A., Hastings, W. J., Fahey McGrath, L., Leitz-Langan, M., Magis, A. T., Coppess, S. M., & Komac, W. (2026). Novel oral LNAD+ increases intracellular NAD and metabolic flux without elevating catabolites in a randomised, placebo-controlled Phase 0/1b trial in healthy adults [Preprint]. bioRxiv. https://doi.org/10.1101/2026.03.25.714130
[6] Ministrini, S., Liberale, L., Erle, H.-E., Percoco, G., Tfayli, A., Assi, A., Kapitonov, I., Greiner, I., & Camici, G. G. (2025). A liposomal formulation enhances the anti-senescence properties of nicotinamide adenine-dinucleotide (NAD+) in endothelial cells and keratinocytes. Current Issues in Molecular Biology, 47(9), 722. https://doi.org/10.3390/cimb47090722
[7] Isman, A., Nyquist, A., Strecker, B., Harinath, G., Lee, V., Zhang, X., & Zalzala, S. (2024). Low-dose naltrexone and NAD+ for the treatment of patients with persistent fatigue symptoms after COVID-19. Brain, Behavior, & Immunity – Health, 36, 100733. https://doi.org/10.1016/j.bbih.2024.100733
[8] Gallagher, C., & Emmanuel, O. O. (2026). NAD+ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence. Ageing Research Reviews, 116, 103057. https://doi.org/10.1016/j.arr.2026.103057
[9] Reyna, K., Heinzen, G., Patel, N., Ritter, M., Siojo, A., Legere, H., & Pojednic, R. (2026). Intravenous infusion of nicotinamide adenine dinucleotide (NAD+) versus nicotinamide riboside (NR): A retrospective tolerability pilot study in a real-world setting. Frontiers in Aging, 7, 1652582. https://doi.org/10.3389/fragi.2026.1652582