What is NAD? Dosage, Storage, Benefits, and Side Effects

NAD (nicotinamide adenine dinucleotide) is a naturally present coenzyme that is found in every cell of the body. It exists in two main forms: the oxidized form NAD (NAD+) and the reduced form NADH.

NAD+ in its oxidized state is involved in redox (oxidation-reduction) reactions, which pass electrons through metabolic pathways, including glycolysis, tricarboxylic acid (TCA) cycle, and oxidative phosphorylation.

Beyond its role in energy metabolism [1] , NAD⁺ is a substrate for important enzymes including sirtuins (deacetylases), PARPs (poly(ADP–ribose) polymerases), which are involved [2] in DNA repair, and CD38 (a NAD-consuming enzyme).

It is a well-established fact that the levels of NAD+ decrease with age, and in the case of metabolic stress (obesity, inflammation, poor diet, smoking, etc.).

Because of these roles, there has been interest in the idea of “boosting” NAD (and/or NAD⁺) levels via supplementation or precursor compounds, to support cellular metabolism, mitochondrial health, DNA repair, and possibly the aging process. Let’s read more to see what NAD is.

NAD and Precursors Dosage and Storage

Dosage

Because NAD and its precursors span multiple forms (direct NAD supplementation, intravenous/infusion, precursors such as nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN)), NAD dosage guidance is variable and not yet standardised. Key findings include:

Oral supplementation of NAD+ boosting compounds (particularly NR) in humans: In a review of human trials, oral dosages [3] of NR were 100 mg/day to 1,000 mg/day (or even 2,000 mg/day in other studies) of NR, given for up to a period of about 20 weeks.
For NMN, a 2023 randomized trial (80 healthy middle‐aged adults) evaluated daily oral doses of 300 mg [4] , 600 mg, and 900 mg NMN for 60 days; NAD blood concentrations increased in a dose‐dependent fashion, with good tolerability.
Some article sources mention direct NAD⁺ “injection/infusion” protocols with 500–1,000 mg doses per session, although such regimens are less well validated in rigorous trials.
As an oral dosage of direct NADH [5] (reduced NAD): One source recommends 2.5-5 mg/day to increase nutrition/energy, and 10-15 mg/day in Alzheimer/Parkinson pilot doses.
The American Pharmacists Association has reported [6] that non-prescription NAD+ supplements (usually in capsule, occasionally containing NAD+ or a precursor) are selling between 300 mg/day and 1,000 mg/day.

Given the variability of study designs, populations, formulations (direct NAD⁺ vs precursor vs infusion), and endpoints, no universally accepted dosage is established. Most sources emphasize consulting a health care provider and noting that research is still emerging.

Storage

Because NAD (and its boosted formulations) are typically sold as dietary supplements or given via intravenous or injection in certain wellness/clinic settings, general best‐practice considerations apply:

Store in a cool, dry place away from direct sunlight to maintain stability of the compound (especially in powder or capsule form).
For injectable/infusion forms: Follow the manufacturer’s instructions for storage (i.e., refrigerated or at controlled temperature) and use by the expiry date.
Look at the label always to see how to store it and keep the product in a sealed form until it is used.
Given that regulatory oversight is less stringent for supplements in many jurisdictions, ensure you purchase from reputable suppliers with transparent storage and manufacturing standards.

The Benefits of NAD Supplementation

There are several possible advantages to increasing the potential benefits of NAD+, and scientific research confirms many of them, but many discoveries are still emerging. Supplementation or an increase in the compound NAD+ has shown:

Improved mitochondrial activity [7] and energy metabolism that is essential in muscle performance and endurance.
Improved cognitive function and neuroprotection via DNA repair and neuronal health support.
Positive cardiovascular outcomes, such as control of vascular tone.
Potential slowing of some aging processes through activation of sirtuins and enhanced cellular repair mechanisms.
Support for metabolic health and insulin sensitivity.

Important Caveat

Although such effects are possible, many studies in humans demonstrate that there are no significant changes in key clinical outcomes (insulin sensitivity, body weight, resting energy expenditure, muscle strength) even when NAD+ levels increase. For example:

A 12-week [8] trial of 1000 mg/day NR in obese men found that NAD+-related metabolites increased, and no changes in insulin sensitivity, body composition, or resting energy expenditure were found.
According to a review [9] , NAD+ increase does not always lead to better physiological results.

Side Effects and Safety Profile

The NAD precursors, such as NR and NMN, are typically well tolerated during clinical studies. Side effects relating to NAD intravenous or intramuscular injections are mild, including muscle pains, fatigue, headache, nausea, and pain at the injection site.

There are no significant reported adverse events in the NAD precursors [10] oral supplementation studies, and therefore, it is relatively safe in most cases. However, long-term safety data are still limited, and medical consultation is advised before beginning NAD therapies.

Who Should and Should Not Take NAD?

NAD boosting is mainly aimed at older adults to enhance the deteriorating mitochondrial activity, metabolic well-being, and alleviate oxidative stress.

It may have a positive effect [11] on individuals with metabolic, neurodegenerative, and cardiovascular issues; however, more studies are needed to make conclusive statements.

Patients who have chronic illnesses, pregnant or lactating women, and patients taking drugs are informed to seek medical advice before taking NAD supplements or therapy.

What Are the Best NAD Supplements

Supplement

Direct NAD⁺ supplement: Capsules or powders stating “NAD” or “NAD⁺”. These are less well studied [12] in strict human trials compared to precursors.
NADH supplement: Reduction form of NAD; there are previous trials (small scale) (e.g., 2.5-15 mg/day).

Precursor compounds:

Nicotinamide riboside (NR)
Nicotinamide mononucleotide (NMN)

These have more robust human trial data for raising NAD⁺ levels, and are commonly marketed.

What is NAD vs NAD+? Brief Explanation

NAD is the abbreviated form of Nicotinamide adenine [13] dinucleotide, which is a combination of NAD+ and NADH. NAD+ is the oxidized, active form essential for accepting electrons during cellular respiration and activating enzymes involved in repair and longevity.

The reduced form is called NADH, and it donates electrons to generate ATP. The ratio between NAD+ and NADH triggers energy metabolism and redox homeostasis.

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