NAD+ Tablets: Do the Delivery Claims Match the Evidence?

Written by the Nuvirox Research Team

Short answer: format probably matters less than marketers suggest, and the science here is almost entirely in capsules. Walk into a supplement retailer or scroll Amazon and you'll find NAD+ precursor supplements in tablets, sublingual lozenges, nasal sprays, liposomal softgels, and powders — often with claims of "superior absorption" or "bypassing first-pass metabolism." These are plausible-sounding hypotheses. They are not proven in human beings. Every single randomized controlled trial that has successfully raised blood NAD+ levels in humans has used a plain oral capsule or powder swallowed with water. That's a fact worth leading with before we discuss the format options.

What formats are NAD+ precursor supplements actually sold in?

The market has fragmented considerably. The four main categories you'll encounter are:

Standard oral capsules. These are the format used in virtually all published human RCTs. NR or NMN is packed into a vegetable or gelatin capsule and swallowed. The precursor survives gastric acid reasonably well and is absorbed in the small intestine via specific transporters — equilibrative nucleoside transporters for NR, and a dedicated NMN transporter (Slc12a8, though its human relevance is still debated). This is the format with actual human evidence behind it.

Sublingual tablets or lozenges. Designed to dissolve under the tongue, allowing absorption through the oral mucosa and bypassing first-pass hepatic metabolism. The rationale is borrowed from drugs like nitroglycerin where sublingual delivery is well-established. For NAD+ precursors specifically, no published peer-reviewed human RCT has compared sublingual to capsule bioavailability. Brands cite unpublished internal data or extrapolate from unrelated compounds.

Liposomal softgels. The precursor is encapsulated in phospholipid vesicles intended to improve intestinal absorption. One small human study of liposomal NR does exist (showing a modest absorption advantage at lower doses), but that same study found that the liposomal advantage did not compensate for the dose reductions liposomal products often use to justify the format. This is covered more deeply in our analysis of liposomal NR.

Powder and nasal sprays. Powders are simply capsules without the shell — functionally equivalent if the dose matches. Nasal sprays are an emerging fringe format with no human efficacy data for NAD+ precursors as of mid-2026.

Does the tablet vs. capsule distinction matter for absorption?

For most small-molecule supplements, the pharmacological difference between a standard tablet and a capsule is minor. Both require dissolution in the gut before absorption. Tablets may use binding agents (excipients) that affect disintegration time, but for well-formulated products this difference is clinically insignificant. The meaningful distinctions are between oral delivery (capsules and standard tablets) vs. mucosal delivery (sublingual) vs. parenteral delivery (IV infusion) — not between capsule shell materials.

What does matter: the dose and the form of the precursor. For NR specifically, label claims can be misleading because NR chloride and NR hydrogen malate have different molecular weights — the same milligrams of product contains different amounts of actual NR depending on the salt form. ConsumerLab's independent testing has found products where the stated NR amount was inflated by this salt weight issue. This is a quality concern that applies regardless of whether the product is a capsule, tablet, or lozenge.

What human studies actually show about oral NAD+ precursor delivery

The Martens et al. (2018) crossover trial — NR 500 mg twice daily, capsules. Twenty-four healthy adults aged 55–79 completed a 6-week randomized, double-blind, placebo-controlled crossover. NR chloride capsules at 1,000 mg/day raised whole blood NAD+ by approximately 60% above baseline. This is the foundational human pharmacokinetics study for NR — conducted entirely in standard capsule form. (Nat Commun 2018; DOI: 10.1038/s41467-018-03421-7)

The Okabe et al. (2022) NMN placebo-controlled trial — 250 mg/day, capsules. Thirty healthy adults received 250 mg/day oral NMN or placebo for 12 weeks in a randomized, double-blind, parallel-group design. Whole blood NAD+ levels rose significantly in the NMN group vs. placebo; no serious adverse events were observed. (Nat Commun 2022; DOI: 10.1038/s41467-022-28765-2)

The honest counterweight: no head-to-head format comparison exists. No published, peer-reviewed randomized human trial has compared capsule vs. sublingual vs. liposomal delivery of NR or NMN on NAD+ outcomes. The clinical literature is entirely in oral capsule/powder form. Anyone claiming their tablet format is superior based on "3× bioavailability" or similar figures is citing unpublished marketing claims or animal models, not human RCT data. The fair reading is: we simply don't know whether other formats perform better, worse, or identically to capsules in humans.

What format choice won't change

Even if a sublingual tablet delivered marginally higher peak NR or NMN concentrations, raising blood NAD+ is not the same as demonstrating clinical benefit. Most human trials have shown consistent NAD+ elevation from capsules — but the functional outcomes (energy, cognition, cardiovascular markers) remain inconsistent across trials, largely because the studies are short, small, and heterogeneous. A fancier delivery format doesn't resolve the more fundamental question of what sustained NAD+ elevation actually does in healthy adults. If your goal is to evaluate whether NAD+ precursor supplementation works for you, the most evidence-aligned approach is a standard oral capsule at a dose matching clinical trials, not a premium-format product with unverified absorption claims.

See a doctor if: you're considering NAD+ supplementation because of persistent fatigue, cognitive changes, or metabolic concerns. These symptoms can have medical causes that supplementation won't address. A physician can help rule out underlying conditions before you spend money on supplements.

What dose and timing does the evidence support?

Human trial doses have ranged from 250 mg/day to 2,000 mg/day for both NR and NMN. The most commonly studied doses — and those showing consistent NAD+ elevation — cluster around 300–1,000 mg/day. The Martens NR trial used 1,000 mg/day; the Okabe NMN trial used 250 mg/day. There's no strong evidence from human studies that doses above 1,000 mg produce proportionally greater benefit, though tolerability at higher doses appears acceptable. Timing (morning vs. evening, with or without food) has not been systematically compared in published trials — most studies used morning administration with food.

Frequently asked questions

Is a sublingual NAD+ tablet better than a capsule?
No human RCT has tested this comparison. Sublingual delivery is theoretically plausible (and well-established for other drugs), but for NAD+ precursors specifically there is no peer-reviewed evidence showing it outperforms standard oral capsules. Until that data exists, the format with the actual evidence behind it remains the standard capsule.

Can you take NAD+ as a direct supplement rather than a precursor?
Oral NAD+ itself is poorly absorbed — the molecule is too large and charged to cross intestinal membranes efficiently. This is why all studied supplements use precursors (NR, NMN, niacin, niacinamide) that the body converts to NAD+ inside cells. Products sold as "NAD+" itself are generally NR- or NMN-based despite the branding.

Does the tablet binder or filler matter?
For most people, standard tablet excipients (microcrystalline cellulose, magnesium stearate) are nutritionally inert and clinically insignificant. If you have specific allergies or dietary restrictions, check the "Other Ingredients" list — but the binders themselves don't meaningfully affect NAD+ outcomes.

Why do companies claim "superior bioavailability" for their tablet or sublingual format?
Several reasons: the claims are often based on in vitro dissolution studies, animal pharmacokinetic data, or unpublished internal testing — none of which is the same as a peer-reviewed human RCT. "Bioavailability" in supplement marketing often means absorption of the compound from the gut, not the downstream NAD+ effect in tissues. These are different things. Healthy skepticism is warranted.

The bottom line

The format you take your NAD+ precursor in matters far less than the ingredient and the dose. Every human trial that has shown measurable NAD+ elevation used standard oral capsules. Sublingual tablets, nasal sprays, and premium liposomal softgels carry plausible mechanistic rationales — but no peer-reviewed RCT head-to-head evidence in humans. If you're evaluating NAD+ supplements, focus on: the specific precursor (NR or NMN, with the most human evidence), the milligrams of actual precursor per serving, and third-party purity testing. For a deeper look at what precursors have the most evidence behind them, see our comparison of NR vs. NMN vs. NAD+, and for what to look for in a specific product, our guide to choosing a quality NAD+ supplement.

References

1. 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. DOI: 10.1038/s41467-018-03421-7
2. Okabe K, et al. Oral administration of nicotinamide mononucleotide is safe and efficiently increases blood NAD+ levels in healthy subjects. Nat Commun. 2022;13:1070. DOI: 10.1038/s41467-022-28765-2
3. Trammell SA, et al. Nicotinamide riboside is uniquely and orally bioavailable in mice and humans. Nat Commun. 2016;7:12948. DOI: 10.1038/ncomms12948. PMID: 27721479
4. Freeberg KA, et al. Nicotinamide riboside supplementation for treating elevated systolic blood pressure and arterial stiffness in midlife and older adults. Front Cardiovasc Med. 2022;9:881703. DOI: 10.3389/fcvm.2022.881703
5. ConsumerLab.com. NAD Booster Supplements Review (NAD+/NADH, Nicotinamide Riboside, NMN). Updated 2026. [consumerlab.com]

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.