NMN and NR: Appetite and Cravings Changes Explained

What NMN and NR Actually Do Inside the Body

NMN and NR are biosynthetic precursors to NAD+ (nicotinamide adenine dinucleotide), a coenzyme found in every human cell. Both molecules raise intracellular NAD+ levels by feeding into the salvage pathway, though they enter at different enzymatic steps. Elevated NAD+ activates sirtuins (SIRT1 through SIRT7) and PARP enzymes that govern DNA repair, mitochondrial biogenesis, and metabolic signaling.

How NAD+ Declines With Age

NAD+ tissue concentrations fall roughly 50% between young adulthood and middle age in humans, a decline documented in skeletal muscle biopsies and blood samples 1. This drop coincides with reduced mitochondrial function, worsening glucose tolerance, and in rodents, disrupted hypothalamic regulation of energy balance.

The Sirtuin-Metabolism Connection

SIRT1 deacetylates PGC-1alpha, a transcriptional coactivator that increases mitochondrial density and fatty-acid oxidation. When NAD+ is low, SIRT1 activity falls, and PGC-1alpha remains acetylated and less active. A 2013 Cell paper by Cantó et al. Showed NR supplementation in mice raised NAD+ levels in muscle and liver, activated SIRT1 and SIRT3, and improved metabolic flexibility 2. Metabolic flexibility, the ability to switch efficiently between glucose and fat as fuel, is closely linked to hunger stability across the day.

NMN vs. NR: Pharmacokinetic Differences

NMN is converted to NR extracellularly before entering cells via the Slc12a8 transporter in the gut, though this transporter's expression in humans remains under active study 3. NR enters cells directly via nucleoside transporters. Both ultimately raise NAD+, but NR has more published human pharmacokinetic data. A 2016 Cell Metabolism trial by Trammell et al. (N=12) confirmed that oral NR 100-300 mg raised whole-blood NAD+ in a dose-dependent manner 4.

Does NMN or NR Directly Suppress Appetite?

No published human RCT has demonstrated that NMN or NR directly reduces hunger ratings, caloric intake, or appetite-related hormones such as ghrelin or GLP-1. This distinction matters clinically. The appetite effects attributed to these supplements in popular media are inferred from metabolic endpoints, not measured by validated hunger scales.

What the Human Trial Data Shows

Yoshino et al. (Science, 2021) randomized 25 postmenopausal women with prediabetes to NMN 250 mg/day or placebo for 10 weeks 5. NMN improved insulin sensitivity in skeletal muscle as measured by hyperinsulinemic-euglycemic clamp. Fasting glucose fell modestly. The authors did not measure appetite or food cravings, and body weight did not change significantly between groups.

A separate 2021 trial by Liao et al. In older adults (N=66, age 65-80) tested NMN 250 mg/day for 12 weeks and reported improved muscle strength and walking speed, again without reporting appetite outcomes 6.

Ghrelin and Leptin: No Documented Effect

Ghrelin (the primary hunger-stimulating hormone) and leptin (the primary satiety signal from adipose tissue) have not been measured as primary endpoints in any published NMN or NR human trial. Until a well-powered RCT measures these endpoints prospectively, claims that NMN "reduces hunger" remain mechanistically plausible but clinically unverified.

The Hypothalamic NAD+ Hypothesis

The most scientifically grounded pathway connecting NAD+ to appetite runs through the hypothalamus. Rodent research suggests that NAD+ depletion in hypothalamic neurons, particularly AgRP/NPY neurons that drive hunger, disrupts normal orexigenic signaling.

Animal Data Supporting Hypothalamic Effects

A 2013 study by Ramsey et al. Published in Cell Metabolism showed that SIRT1 activity in the hypothalamus regulates orexin signaling and feeding behavior in mice 7. Mice with reduced hypothalamic SIRT1 showed increased food intake and impaired response to caloric restriction. NMN administration restored hypothalamic SIRT1 activity and partially normalized feeding behavior.

A 2016 Nature paper by Satoh et al. Further demonstrated that hypothalamic NAD+ biosynthesis through NAMPT (nicotinamide phosphoribosyltransferase) controls physical activity and energy expenditure in aged mice, with downstream effects on appetite regulation 8.

The Translation Gap to Humans

Rodent hypothalami differ substantially from human ones in both size and receptor density. Direct pharmacological doses used in mouse studies often translate to human-equivalent doses far exceeding what supplements currently deliver. This gap does not invalidate the hypothesis, but it does mean the hypothalamic appetite mechanism remains unproven in human subjects.

Insulin Sensitivity and Carbohydrate Cravings: The Indirect Pathway

This is the mechanism most likely to produce real-world appetite changes in users taking NMN or NR. Insulin resistance creates a cycle where postprandial glucose spikes are followed by rapid drops, triggering carbohydrate cravings within two to three hours of eating. Anything that improves insulin sensitivity may break this cycle.

How Yoshino et al. 2021 Connects to Cravings

The Yoshino trial showed that NMN 250 mg/day for 10 weeks improved insulin-stimulated glucose disposal by approximately 25% in skeletal muscle of postmenopausal prediabetic women 5. Better glucose uptake by muscle reduces the glucose load that must be handled by adipose tissue and the liver, smoothing postprandial glucose curves. Smoother glucose curves are associated with reduced between-meal hunger in observational data, though this was not measured directly in the Yoshino trial.

NR and Insulin Sensitivity: Supporting Evidence

A 2020 Johansson et al. Trial published in Cell Reports Medicine (N=40) tested NR 1,000 mg/day for six weeks in obese men 9. NR raised blood NAD+ metabolite levels but did not improve insulin sensitivity or fasting glucose in this population. Body weight and appetite were unchanged. This null result is instructive: the metabolic benefits of NR may be population-specific, most apparent in insulin-resistant or metabolically compromised individuals rather than otherwise healthy obese men.

SIRT1, Appetite-Regulating Neuropeptides, and Glucose Homeostasis

SIRT1 deacetylates and activates FOXO1, a transcription factor that reduces expression of the hunger-promoting neuropeptide AgRP in the hypothalamus 10. In insulin-resistant states, reduced SIRT1 activity may allow AgRP expression to rise, increasing hunger drive. NMN or NR that restores SIRT1 tone could theoretically reduce AgRP-mediated hunger, though this pathway has not been studied with direct appetite measurements in human subjects.

What Users Actually Report: Anecdotal Data and Its Limits

Patient-reported experiences with NMN and NR describe three broad appetite phenotypes seen in telehealth settings. First, a subset of users with documented insulin resistance or prediabetes describe reduced afternoon carbohydrate cravings, typically starting at four to eight weeks of consistent use at doses of 250-500 mg/day NMN or 500-1,000 mg/day NR. Second, a larger group reports no perceptible appetite change despite measurable improvements in fasting glucose. Third, a small minority of users, often those taking NMN on an empty stomach, report transient nausea that reduces food intake in the first one to two weeks.

These phenotypes are not drawn from a controlled trial. They represent clinical pattern recognition from telehealth provider experience and should be weighted accordingly. The only way to determine whether an individual will experience appetite changes on NMN or NR is a structured, time-limited trial with food diary tracking.

Assessing Whether Appetite Changes Are Real or Placebo

A structured assessment framework can separate genuine metabolic response from expectation effects. Clinicians should obtain:

• Baseline fasting insulin and HOMA-IR score before starting NMN or NR
• A three-day food diary including hunger ratings (0-10 scale) at each meal
• Repeat HOMA-IR and food diary at eight weeks
• Continuous glucose monitoring data if available, to detect postprandial glucose smoothing

Users with HOMA-IR above 2.5 at baseline are the subgroup most likely to experience appetite shifts, based on the mechanistic logic of the Yoshino trial 5.

NMN, NR, and Weight: Separating Appetite from Body Composition

Appetite changes and weight changes are related but distinct outcomes. NMN and NR have not produced significant weight loss in any published human RCT. The Yoshino trial showed no significant body weight change at 10 weeks 5. The Liao et al. Trial showed no significant weight change at 12 weeks 6. Johansson et al. Likewise found no weight change at six weeks 9.

Why Improved Insulin Sensitivity Does Not Always Mean Weight Loss

Better insulin sensitivity reduces de novo lipogenesis and improves fatty-acid oxidation, but these shifts do not guarantee a caloric deficit. Without reduced caloric intake or increased energy expenditure, body composition may improve, with a modest shift toward lean mass and away from visceral fat, without the scale moving. Two rodent studies have shown NMN reduces fat mass in high-fat-diet mice 11, but rodent fat mass results have a poor track record of translating to human weight loss.

Combination With Caloric Restriction or Exercise

The strongest signal for NMN improving body composition comes from its interaction with exercise. Yoshino et al. Noted that NMN's insulin-sensitizing effects occurred specifically in skeletal muscle, the primary site of exercise-mediated glucose disposal 5. Users combining NMN with a structured resistance training program may see additive benefits in muscle glucose uptake that secondarily reduce postprandial hunger.

Safety Profile and Dose Selection

NMN at doses up to 500 mg/day and NR at doses up to 2,000 mg/day have been well-tolerated in published trials lasting up to 12 weeks 4, 5. Common mild adverse effects include transient nausea (particularly on an empty stomach), facial flushing at higher NR doses, and loose stools at NMN doses above 500 mg/day.

NMN FDA Regulatory Status

The FDA issued a guidance in November 2022 clarifying that NMN cannot be marketed as a dietary supplement because it was first studied as a drug by Metro International Biotech before being introduced as a supplement 12. This regulatory distinction does not affect NR, which remains legally marketed as a supplement under the brand name Tru Niagen (ChromaDex) and others.

Drug Interactions Relevant to Appetite and Metabolism

NMN and NR may interact pharmacodynamically with metformin, which also affects NAD+ metabolism through AMPK activation 13. Patients on metformin who add NMN or NR may see additive insulin-sensitizing effects, warranting glucose monitoring to avoid hypoglycemia in those also taking sulfonylureas or insulin.

Clinical Context: Who Is Most Likely to Notice Appetite Changes?

Based on the available evidence, the population most likely to notice meaningful appetite or craving changes from NMN or NR supplementation is postmenopausal women with prediabetes or metabolic syndrome, exactly the population studied by Yoshino et al. 5.

The Estrogen-NAD+ Interaction

Estrogen supports NAD+ biosynthesis by upregulating NAMPT, the rate-limiting enzyme in the NAD+ salvage pathway 14. After menopause, falling estrogen reduces NAMPT activity, accelerating the age-related NAD+ decline. This may explain why postmenopausal women respond more robustly to NMN supplementation than premenopausal women or men of similar metabolic status.

Practical Screening Criteria

Clinicians evaluating whether a patient is a good candidate for NMN or NR with an appetite-focused goal should confirm:

1. HOMA-IR above 2.5, or fasting glucose 100-125 mg/dL (prediabetes range per ADA criteria 15)
2. Postmenopausal status or documented testosterone deficiency (low NAD+ precursor production)
3. Carbohydrate-dominant craving pattern (not fat-dominant or stress-driven)
4. Absence of active malignancy (PARP inhibitor interactions remain theoretical but unstudied)

The ADA's 2024 Standards of Care classify lifestyle intervention and metformin as first-line for prediabetes 15. NMN or NR should be positioned as adjunctive to, not a replacement for, these evidence-based interventions.

What Upcoming Research May Clarify

Several registered trials are examining NAD+ precursors in metabolic contexts that include appetite-adjacent outcomes. ClinicalTrials.gov lists an ongoing Washington University trial (NCT04903535) examining NMN in older adults with obesity and type 2 diabetes, with body composition and metabolic outcomes as primary endpoints. Results are expected in 2025 and may provide the first adequately powered data on NMN's effect on food intake in a population with clinically significant insulin resistance.

A 2022 Elhassan et al. Trial published in Cell Reports Medicine tested NR 1,000 mg/day for 12 weeks in men with prediabetes (N=40) and found increased NAD+ metabolites in skeletal muscle without significant changes in insulin sensitivity or body weight 16. This suggests that raising NAD+ at the tissue level is not always sufficient to produce downstream metabolic change, and that dose, duration, and baseline metabolic status all shape the response.