90-Day Guarantee
Try it for 90 days. If it isn't right, we'll refund the unused portion — no return shipping, no hassle.
One capsule. Every morning.
Take one capsule with 6–8 oz of water, with or without food.
Clinical studies of NMN have typically run 8 to 12 weeks.* Consistency matters more than timing.
NAD+ starts upstream.
NAD+ is a coenzyme present in every living cell, where it participates in energy metabolism and enzyme function.
Cells produce NAD+ through the salvage pathway. NMN is the molecule that pathway begins with.
SIGNAL provides 500 mg of β-Nicotinamide Mononucleotide per capsule — the upstream input, not the end product.*
One active ingredient. No guessing.
β-Nicotinamide Mononucleotide (β-NMN) — 500mg
The direct cellular precursor to NAD+. This is the molecule researchers at Washington University School of Medicine, Harvard Medical School, and Keio University have studied in human trials.* No proprietary blend. No hidden dose. The full 500mg is listed in the name.
HPMC — Vegetable Capsule
Plant-derived, vegan. No gelatin, no animal byproducts.
Microcrystalline Cellulose · Silicon Dioxide · Magnesium Stearate
Standard functional excipients required for capsule manufacturing integrity. Included because the capsule needs them.
What you won't find:
No artificial colors · No artificial flavors · No gluten · No lactose · No allergens · No antibiotics · No hormones · No alcohol
Certifications:
Vegan · Gluten Free · Lactose Free · Allergen Free · Halal · Manufactured in a GMP-certified, FDA-registered facility in the USA.
A 2024 meta-analysis of 12 randomized controlled trials covering 513 participants found a significant overall effect of oral NMN supplementation on blood NAD+ levels. (Zhang J, Poon ETC, Wong SHS. Crit Rev Food Sci Nutr 2025;65(22):4382-4400. PMID 39116016)
In a randomized, double-blind, placebo-controlled trial, 250 mg/day of NMN for 12 weeks in older adults produced significantly higher blood NAD+ and its metabolites versus placebo, alongside a significantly shorter 4-metre walking time. (Morifuji M, Higashi S, Ebihara S, Nagata M. GeroScience 2024;46(5):4671-4688. PMID 38789831)
A multicenter dose-ranging trial in 80 healthy middle-aged adults tested 300, 600, and 900 mg daily for 60 days. All doses raised blood NAD+; safety and tolerability were established across the range. (Yi L, Maier AB, Tao R, et al. GeroScience 2023. DOI 10.1007/s11357-022-00705-1)
Meta-analyses of NMN trials have found no significant effect on fasting glucose, insulin, HbA1c, HOMA-IR, or lipid profile. Happy Cells makes no claims in those areas.
These studies tested the ingredient, not SIGNAL.*
Human trials have studied oral NMN at 250 mg to 1,200 mg daily over 4 to 12 weeks. SIGNAL provides 500 mg per capsule, within that studied range. There is no established optimal dose, and no evidence that higher doses produce proportionally greater effects.
In published human trials, oral NMN has been well tolerated at doses up to 1,200 mg per day for six weeks and 900 mg per day for eight weeks. Long-term safety beyond these study periods has not been established.
NMN has not been studied in pregnancy, breastfeeding, or in people under 18. Anyone taking prescription medication, managing a medical condition, or scheduled for surgery should consult a qualified healthcare professional before use.
Clinical trials have not identified a consistent pattern of serious adverse effects in healthy adults. Some participants have reported mild digestive discomfort, headache, or changes in sleep. Reported effects have generally been mild and short-lived.
Published trials have typically run 8 to 12 weeks. Blood NAD+ increases have been measured as early as week 4 in some studies. Individual results vary and are not guaranteed.
Both are NAD+ precursors that enter the salvage pathway. NR is nicotinamide riboside; NMN is nicotinamide mononucleotide, one step further along the pathway. Both have human trial data showing increased blood NAD+. Head-to-head comparisons in humans are limited.
Yes. In September 2025 the FDA concluded that NMN is not excluded from the definition of a dietary supplement, reversing its 2022 position, and reinstated prior New Dietary Ingredient acknowledgments in December 2025. NMN remains a New Dietary Ingredient subject to NDI notification requirements.
NMN is present in small amounts in foods including broccoli, avocado, edamame, cucumber, and tomatoes. The quantities are far below the doses used in human trials.
Try it for 90 days. If it isn't right, we'll refund the unused portion — no return shipping, no hassle.
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