Not medical advice. I am a software engineer, not a physician. This page documents my own protocol and the research I read while building it. Talk to a qualified clinician before changing your supplementation, diet or any treatment. Lab reference ranges quoted here vary by laboratory and by individual.
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Nicotinamide Mononucleotide (NMN) is the most direct precursor to NAD+ (nicotinamide adenine dinucleotide) — arguably the most important molecule in cellular biology after ATP. NAD+ is required by over 500 enzymatic reactions in the body, including DNA repair (PARPs), gene silencing and longevity (sirtuins SIRT1-7), mitochondrial energy production, circadian rhythm regulation, and immune cell function. The problem: NAD+ levels decline by approximately 50% between ages 40 and 60, and this decline is now considered a hallmark of biological aging.
NMN is converted to NAD+ in a single enzymatic step via NMNAT (nicotinamide mononucleotide adenylyltransferase). This is the shortest biosynthetic pathway to NAD+, shorter than the pathway from NR (nicotinamide riboside), which must first be converted to NMN before becoming NAD+. The ProHealth NMN Pro Complete formula combines NMN with TMG (trimethylglycine) as a methyl donor to support the methylation demands of NAD+ metabolism, and resveratrol as a sirtuin activator to amplify the downstream benefits of restored NAD+ levels.
NMN enters cells through the Slc12a8 transporter (identified in 2019) and is converted to NAD+ by NMNAT enzymes in a single step. This is the penultimate step in the salvage pathway, which recycles nicotinamide (a byproduct of sirtuin and PARP activity) back into NAD+. By supplementing NMN directly, you bypass the rate-limiting NAMPT step that becomes slower with age, directly feeding the final enzymatic reaction. Human studies show that oral NMN supplementation (250-1200 mg/day) raises blood NAD+ levels within hours.
Sirtuins are NAD+-dependent deacetylases that regulate aging at the epigenetic level. SIRT1 deacetylates histones and transcription factors, silencing genes associated with inflammation and activating those associated with stress resistance and longevity. SIRT3 in mitochondria enhances oxidative phosphorylation efficiency and reduces superoxide production. SIRT6 directly participates in DNA double-strand break repair. All seven sirtuins require NAD+ as a co-substrate — when NAD+ levels decline with age, sirtuin activity drops proportionally, accelerating the aging process.
Poly(ADP-ribose) polymerases (PARPs) are the first responders to DNA damage. When a DNA strand breaks, PARP1 detects the break within seconds and consumes NAD+ to build poly(ADP-ribose) chains that recruit repair machinery. PARP activity accounts for 30-60% of total cellular NAD+ consumption. As DNA damage accumulates with age and NAD+ levels decline, a vicious cycle emerges: more damage to repair but less NAD+ fuel for the repair enzymes. Restoring NAD+ via NMN helps break this cycle.
Why TMG matters: When sirtuins and PARPs consume NAD+, they release nicotinamide as a byproduct. Nicotinamide is recycled back to NAD+ via the salvage pathway, but this process requires methylation (via NNMT). High NMN supplementation increases methylation demand, which can deplete methyl donors. TMG (trimethylglycine/betaine) provides the methyl groups needed to sustain this cycle without depleting homocysteine-lowering methylation capacity.
| Parameter | Detail |
|---|---|
| Product | ProHealth Longevity — NMN Pro Complete |
| Dose | 4 capsules (contains NMN + TMG + resveratrol) |
| Timing | With breakfast (morning dosing aligns with circadian NAD+ peak) |
| Key actives | NMN (direct NAD+ precursor) + TMG (methyl donor) + Resveratrol (sirtuin activator) |
| Notes | Morning dosing is preferred because NAD+ naturally peaks in the first half of the day and is involved in circadian clock regulation. Taking NMN at night may disrupt sleep in some individuals. |
Human NMN clinical trials have accelerated since 2021, confirming safety and demonstrating measurable increases in blood NAD+ levels, improved muscle insulin sensitivity, and enhanced aerobic capacity in older adults.
Yi, L., et al. (2023). The efficacy and safety of beta-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. GeroScience, 45(1), 29-43. PubMed 36482258
Covarrubias, A. J., et al. (2021). NAD+ metabolism and its roles in cellular processes during ageing. Nat Rev Mol Cell Biol, 22(2), 119-141. PubMed 33888596
Yoshino, J., et al. (2018). NAD+ Intermediates: The Biology and Therapeutic Potential of NMN and NR. Cell Metab, 27(3), 513-528. PubMed 31316452
A February 2026 systematic review and meta-analysis of adults with elevated blood pressure (n=349, across 4–12 week studies) found that NMN supplementation was associated with a reduction of 2.15 mmHg in diastolic blood pressure and was well tolerated with only mild adverse events. A February 2026 anti-inflammatory study in healthy men (n=11) found that NMN supplementation at 1,200 mg/day reduced inflammatory signals after intense exercise over 7 days. However, a meta-analysis noted that while NMN significantly elevates blood NAD+ levels, most clinically relevant outcomes were not significantly different between NMN and control groups. In older adults (ages 60–83), NMN showed no significant effects on skeletal muscle mass or strength, and researchers caution that the benefits of NMN supplementation may be exaggerated in the current market.
There is no widely available direct NAD+ blood test for consumers yet. However, several downstream markers serve as indirect indicators of the metabolic improvements driven by NAD+ restoration.
ProHealth Longevity — NMN Pro Complete (120 capsules) — $110.96 on iHerb.
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April 2026 Systematic Review: A PRISMA-guided review in Ageing Research Reviews confirmed that oral NR/NMN reliably raises NAD-related biomarkers in humans, but clinical effects on metabolic, vascular, and performance outcomes remain mixed. Longer, adequately powered RCTs with clinically meaningful endpoints are still needed. Source