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Longevity Stack

Evidence Stack

Healthy aging · NAD+ salvage · autophagy · mitochondrial antioxidant

Evidence-first healthy-aging biomarker stack — what the human-evidence record actually shows for the ingredients most associated with longevity, including the honest distinction between lifespan (never measured in a supplement RCT) and healthspan biomarker shifts (NAD+ pool, walking speed, grip strength, skin moisture, fatigue) that the trials do document. This is mechanism and evidence mapping, not medical advice. No anti-aging or lifespan-extension claim is adopted; discuss any longevity supplementation with a healthcare provider. All PubMed identifiers are verified against PubMed before inclusion; cross-market regulatory claims appear verbatim per their authorising authority (FDA · EFSA · ANVISA · TGA).

Last reviewed · How we assess evidence →

Quick Summary

  • NAD+ salvage is the most replicated longevity biomarker target. Oral NMN at 250 to 1000 mg/day raises blood NAD+ to approximately twice baseline across multiple RCTs (Yoshino 2021 PMID 33888596, Yi 2022 PMID 36482258, Okabe 2022 PMID 35479740, Pencina 2023 PMID 36740954, Zhang 2025 meta-analysis of 12 RCTs n=513 PMID 39116016). Functional endpoints (walking speed, grip strength, sit-to-stand, sleep) are positive in older adults; cardiovascular surrogates trend but do not yet reach statistical significance. See /ingredients/nmn/.
  • Astaxanthin evidence is robust for skin and fatigue, moderate / mixed for cardiometabolic. Meta-analytic support for skin moisture and elasticity (Zhou 2021 PMID 34578794), fatigue/motor function (Liu 2024 PMID 38243785), and a partial HDL-C/blood-pressure signal (Xia 2020 PMID 32755613). BMI / body-weight regulation pooled effect was not significant — astaxanthin is not a "fat burner."
  • Spermidine, resveratrol, and urolithin A evidence is preliminary / emerging. Scientifically interesting longevity candidates with strong preclinical mechanism but limited clinical-endpoint translation. Treat them as exploratory.
  • Lifespan as an endpoint has not been measured for any supplement in published human RCTs. The available longevity evidence is preclinical or epidemiological. This page maps mechanism and biomarker evidence honestly — it does not extrapolate beyond what the trials measured.
  • This is not medical advice. The stack below is mechanism and evidence mapping — discuss any longevity supplementation with a healthcare provider, particularly if you take glucose-lowering medications, anticoagulants, or are pregnant or lactating.

The Evidence Stack

The "evidence" column below describes the strength and direction of the outcome evidence in qualitative terms — well-established, robust, moderate/mixed, preliminary/emerging, or null/negative. The S/A/B/C tier that grades how extensively an ingredient is studied (its evidence volume) lives on each linked ingredient page, not here.

Ingredient Healthy-aging evidence (qualitative) Key Trial / Meta-analysis asxan.ai page
NMN Robust for NAD+ biomarker elevation (~2× baseline); moderate / mixed for functional endpoints (walking speed, grip strength positive in older adults; cardiovascular surrogates trend, not yet significant) Yi 2022 PMID 36482258 (dose-finding); Igarashi 2022 PMID 35927255 (older men functional); Kim 2022 PMID 35215405 (chronobiology); Zhang 2025 meta PMID 39116016 /ingredients/nmn/
Astaxanthin Robust for skin moisture/elasticity and fatigue/motor function; moderate / mixed for cardiometabolic; BMI/body-weight null Zhou 2021 PMID 34578794 (skin meta); Liu 2024 PMID 38243785 (fatigue meta); Xia 2020 PMID 32755613 (CV meta) /ingredients/astaxanthin/
Spermidine Preliminary / emerging — autophagy-induction mechanism strong in preclinical models; clinical-endpoint translation limited Preclinical autophagy-induction literature; early-phase human trials /ingredients/spermidine/
Resveratrol Preliminary / emerging — SIRT1-activation mechanism debated; clinical-endpoint translation limited Polyphenol SIRT1-axis mechanism literature (directness debated) /ingredients/resveratrol/
Urolithin A Preliminary / emerging — mitophagy-induction mechanism plausible; clinical-endpoint translation limited Preclinical mitophagy-induction literature; early-phase human trials /ingredients/urolithin-a/

How It Works

Each ingredient engages a different subset of the Hallmarks of Aging — NMN through NAD+ salvage and sirtuin co-substrate supply, astaxanthin as a mitochondrial-membrane antioxidant, spermidine through bulk autophagy, urolithin A through selective mitophagy, and resveratrol through the debated SIRT1 axis. Biochemical engagement is not equivalent to a measured longevity endpoint in humans.

The Lopez-Otin "Hallmarks of Aging" framework (cellular senescence, mitochondrial dysfunction, loss of proteostasis, deregulated nutrient sensing, epigenetic alteration, and others) is the most-cited mechanistic scaffold in longevity research. The ingredients on this page each target a subset of these hallmarks at the biochemical level — though biochemical engagement is not equivalent to a measured longevity endpoint in humans.

NAD+ salvage and Sirtuin activation. NMN is the direct biosynthetic precursor to NAD+ in the salvage pathway, used as substrate by NMNAT1/2/3 to regenerate NAD+. NAD+ is a co-substrate for sirtuins (SIRT1-7), PARP enzymes, and CD38; salvage-pathway flux is hypothesized to decline with age. Bonkowski & Sinclair 2016 (PMID 27552971, Nat Rev Mol Cell Biol) synthesise the rationale for NAD+ and sirtuin-activating-compound (STAC) research and explicitly frame the mechanistic case while noting that a human longevity-endpoint result remains absent from the published trials. The mechanistic detail is reproduced on the NMN ingredient page (see /ingredients/nmn/#mechanism).

Cognitive-axis adjuncts (mechanism, not lifespan). Omega-3 long-chain EPA/DHA are the most-replicated non-NAD+ nutritional inputs into brain mitochondrial-membrane composition. Yurko-Mauro 2015 SR+MA (PMID 25786262, PLoS One) reported modest but statistically significant effects of DHA on episodic memory in older adults with mild cognitive complaint; Mocking 2016 MA-regression (PMID 26978738, Transl Psychiatry) reported significant effect of EPA-predominant omega-3 on depressive symptoms; Martineau 2017 IPD meta (PMID 28202713, BMJ) reported significant reduction in acute respiratory infection with vitamin D3 in deficient subgroups. These adjuncts are cognitive and immune support during aging — the published RCTs do not include a lifespan endpoint. Omega-3 is covered at /ingredients/omega-3/ with standalone EPA (fish-first) and DHA (algae first-line) monomer pages.

Autophagy and mitophagy. Spermidine is the most-studied dietary autophagy inducer in preclinical models, and urolithin A (a gut-microbiome metabolite of ellagitannins) is the most-studied dietary mitophagy inducer. Both have mechanistic preclinical literature; both have early-phase human trials; neither yet has meta-analytic evidence on healthy-aging clinical endpoints. (Note on PMID transparency: a frequently circulated attribution to a "Mehmel 2020" urolithin A older-adult RCT does not return a verifiable PubMed record under that author and title. Until a 4-dimension PASS PubMed citation is established, asxan.ai treats the urolithin A older-adult mitophagy literature as preclinical-plus-early-phase only.)

Mitochondrial antioxidant defense. Astaxanthin's xanthophyll structure crosses the mitochondrial inner membrane and is the most-cited reason for its ROS-scavenging behavior in vitro. The translation to human clinical endpoints is partial: skin and fatigue meta-analyses are positive; cardiometabolic outcomes are mixed; cognition trials in healthy adults are not yet definitive (Liu 2024 PMID 38243785).

Sirtuin / SIRT1 activation. Resveratrol is the original "SIRT1 activator" in the polyphenol literature, but the directness of the mechanism (allosteric activation vs. indirect AMPK pathway) remains debated. Treat the mechanism as scientifically interesting but not fully resolved.

Body systems engaged: DNA & Epigenetic · Cellular Renewal · Mitochondrial & Cellular Energy. Mechanism tags: Epigenetic regulation · Autophagy / Mitophagy · Sirtuin activation.

What the Trials Show — Including the Nulls

Astaxanthin BMI / body-weight regulation is not significant. The Xia 2020 meta-analysis (PMID 32755613) reported significant HDL-C improvements and partial blood-pressure signals but non-significant pooled effects on BMI and body weight. Astaxanthin should not be characterized as a fat burner or weight-loss supplement.

Astaxanthin cognition in healthy adults is unsettled. The Liu 2024 meta-analysis (PMID 38243785) reported significant pooled effects on fatigue and motor function, but the cognition signal was a directional trend that did not consistently reach statistical significance. Astaxanthin is not a "cognitive enhancement" supplement.

Spermidine, resveratrol, urolithin A clinical-endpoint evidence is preliminary / emerging. Treat the cluster as preclinical / early-phase research rather than as clinical-grade evidence — do not assume the popular longevity positioning of any of the three maps to high-quality meta-analytic evidence.

Stacking & Timeline

Mechanistic pairings are plausible but rarely backed by head-to-head synergy trials; realistic timelines run from weeks (NAD+ biomarker shift, skin moisture) to months (functional endpoints), with no lifespan endpoint at any timepoint.

Mechanistic pairs

Synergy in supplement science is a higher bar than additive effect — formally, it requires a clinical-endpoint trial demonstrating that the combination outperforms the sum of components. That bar is rarely cleared in the published literature. The pairings below are mechanistic complementarity, not RCT-demonstrated synergy.

NMN + Astaxanthin · mitochondrial-axis pair. NMN raises NAD+ supplying co-substrate for sirtuin and PARP enzymes; astaxanthin engages mitochondrial-membrane antioxidant capacity. Both share the mitochondrial-quality target, on different molecular axes. No head-to-head clinical synergy trial has been published.

Spermidine + Urolithin A · proteostasis-mitophagy pair (preclinical, mechanism only). Spermidine engages bulk macroautophagy and urolithin A engages selective mitophagy at the preclinical mechanism level. No human clinical-endpoint synergy trial. The pairing is hypothesis-generating, not evidence-confirmed.

Resveratrol + NMN · sirtuin-axis pair (mechanism, debated). Resveratrol is the historically claimed SIRT1 activator; NMN raises NAD+ as sirtuin co-substrate. The mechanistic logic is direct, but neither the directness of the resveratrol-SIRT1 mechanism nor the resveratrol clinical-endpoint evidence base is fully resolved.

When to see results — realistic timeframes

4 weeks · NAD+ biomarker shift (NMN). Okabe 2022 (PMID 35479740) reported blood NAD+ approximately doubled by week 4 versus placebo at 250 mg/day, maintained through week 12. This is a biomarker shift, not a functional outcome.

8 weeks · skin moisture and elasticity (astaxanthin). The Zhou 2021 meta-analysis (PMID 34578794, n=481 RCT subset) reported significant pooled effects on skin moisture (SMD 0.49, p < 0.001) and elasticity (SMD 0.46, p < 0.05). Trial durations were typically 4 to 16 weeks; the modal trial reported significant change by week 8.

12 weeks · functional endpoints in older adults (NMN). Igarashi 2022 (PMID 35927255) reported statistically significant improvements in walking speed (p = 0.033) and left-hand grip strength (p = 0.019) in healthy older Japanese men at 250 mg/day for 12 weeks. Kim 2022 (PMID 35215405) reported afternoon-dosing-specific improvements in sleep, fatigue, and sit-to-stand in older Japanese adults at 250 mg/day for 12 weeks — one of the more reproducible timing-of-administration findings in the supplement literature.

12 weeks · insulin sensitivity in prediabetic women (NMN). Yoshino 2021 (PMID 33888596, Science) reported significant improvement in skeletal-muscle insulin sensitivity at 250 mg/day in postmenopausal women with prediabetes — the most-cited mechanistic-translational NMN RCT. The endpoint is a metabolic surrogate, not lifespan.

6 weeks · amateur runner aerobic capacity (NMN). Liao 2021 (PMID 34238308, J Int Soc Sports Nutr) reported dose-dependent improvement in aerobic capacity (ventilatory threshold) at 600–1200 mg/day for 6 weeks in amateur runners. Note: amateur athletic, not older-adult longevity.

Dose-response meta · cardiometabolic surrogate (NMN). Zhang 2025 (PMID 39116016, Crit Rev Food Sci Nutr) pooled 12 RCTs (n = 513) and reported significant favorable shifts in glucose / lipid surrogate panels, with effect-size heterogeneity by dose, duration, and baseline status.

6 months and beyond · longevity-biomarker durability. Most published NMN and astaxanthin RCTs do not exceed 6 months; safety data extend to 1250 mg/day NMN for 4 weeks (Fukamizu 2022 PMID 36002548) and 40 mg/day astaxanthin for 12 weeks (Kupcinskas 2008 PMID 18467083). Longer-term durability and long-tail safety beyond 12 months are not yet established for this stack.

  • Cognitive Support — overlapping mitochondrial-antioxidant logic with astaxanthin and NMN.
  • Heart Health — cardiovascular surrogate endpoints overlap with longevity surrogate endpoints; the negative-null finding on NMN baPWV is reproduced there.
  • Senior 60+ — life-stage page where the older-adult functional-endpoint NMN trials (Igarashi 2022, Kim 2022) are most directly relevant.
  • Intermittent Fasting — autophagy-induction lifestyle context that complements the spermidine and urolithin A mechanism narrative.

Deep-dive long-form evidence reading

For deep-dive narrative on the NAD+-axis longevity evidence base and the antioxidant-axis longevity framing, see the dedicated evidence articles:

Cross-reading these three evidence articles alongside this longevity-stack goal page builds the holistic longevity evidence picture from NAD+ mechanism → precursor decision → antioxidant carotenoid complement.

Frequently Asked Questions

1. Does NMN actually extend lifespan in humans?

No human RCT has measured lifespan as an endpoint. NMN reliably doubles blood NAD+ at 250 to 1000 mg/day (Yi 2022 PMID 36482258, Okabe 2022 PMID 35479740, Pencina 2023 PMID 36740954) and improves functional endpoints in older adults at 250 mg/day for 12 weeks (Igarashi 2022 PMID 35927255). The leap from "NAD+ biomarker rises" to "lifespan extends" is not supported by published human evidence.

2. Is astaxanthin "anti-aging"?

Astaxanthin has robust meta-analytic evidence for skin moisture and elasticity (Zhou 2021 PMID 34578794), which are aspects of skin aging. There is no published evidence for a lifespan endpoint, a reversed-aging endpoint, or pooled significance on wrinkle depth or BMI. The honest framing is "skin moisture and elasticity support with strong meta-analytic backing," rather than the colloquial "anti-aging" label.

3. Why are spermidine, resveratrol, and urolithin A on this page when their clinical evidence is preliminary?

Because they are scientifically interesting mechanism candidates that readers expect to see in a healthy-aging context. Spermidine engages bulk autophagy, urolithin A engages selective mitophagy, and resveratrol engages the debated SIRT1 axis — all with strong preclinical mechanism literature. Listing them lets the page map the mechanism honestly while marking their clinical-endpoint translation as preliminary / emerging rather than overstating it as clinical-grade evidence.

4. What dose of NMN is reasonable for a healthy adult?

Most functional-benefit RCTs in older adults used 250 mg/day (Igarashi 2022 PMID 35927255, Kim 2022 PMID 35215405). Athletic-endpoint trials used 600 to 1200 mg/day. Safety data extend to 1250 mg/day for 4 weeks (Fukamizu 2022 PMID 36002548). The Australian TGA permissible upper limit is 500 mg/day. The afternoon-dosing advantage in older adults (Kim 2022) is one of the more reproducible timing-of-administration findings in the supplement literature.

5. Should I take all five together?

That is not a question this page can answer in the abstract — it depends on goals, baseline diet, medications, and individual risk profile. From an evidence-base perspective, NMN and astaxanthin have the most published human trial support; the other three ingredients (spermidine, resveratrol, urolithin A) are exploratory, with preliminary / emerging clinical evidence. Discuss any longevity stack with a healthcare provider, particularly if you take glucose-lowering medications, anticoagulants, or are pregnant or lactating.

6. Are there contraindications I should be aware of?

Yes. NMN safety in pregnancy, lactation, children, and adolescents is not established — avoid. PARP-inhibitor co-administration in oncology requires medical supervision. Astaxanthin has been studied at up to 40 mg/day with acceptable safety (Kupcinskas 2008 PMID 18467083) but trial duration is typically less than 12 months. Each ingredient page (linked in the Evidence Stack) carries its own Safety and Drug Interactions section — read those before stacking.

7. Where does omega-3 fit in a longevity stack?

Omega-3 long-chain EPA/DHA are the most-replicated nutritional inputs into brain mitochondrial-membrane composition. Yurko-Mauro 2015 SR+MA (PMID 25786262) reported a modest but statistically significant effect of DHA on episodic memory in older adults with mild cognitive complaint; Mocking 2016 MA-regression (PMID 26978738) reported a significant effect of EPA-predominant omega-3 on depressive symptoms. Triglyceride lowering is robust at 2–4 g/day. A lifespan endpoint is not measured. The honest framing is "evidence-supported cognitive and cardiometabolic support during aging," rather than "anti-aging." See /ingredients/omega-3/ plus the standalone EPA and DHA pages.

8. Is the Bonkowski & Sinclair 2016 NAD+ review evidence that "NAD+ slows aging in humans"?

Bonkowski & Sinclair 2016 (PMID 27552971, Nat Rev Mol Cell Biol) is a mechanism review of NAD+ biology and sirtuin-activating compounds (STACs). It synthesizes the rationale for the field — sirtuin engagement, mouse-model longevity signals, mechanistic plausibility — and explicitly notes that translation from mouse longevity-endpoint findings to a human longevity endpoint has not been demonstrated in randomized trials. Treat it as the field's most-cited mechanism reference, not as evidence of a human lifespan-endpoint result.

References

All PMIDs verified against PubMed. Effect sizes are reported as published.

  1. PMID 33888596 · Yoshino 2021 · Science · NMN 250 mg/day · significant skeletal-muscle insulin sensitivity improvement in prediabetic postmenopausal women
  2. PMID 36482258 · Yi 2022 · NMN dose-finding RCT · blood NAD+ ~doubled across 300/600/900 mg/day arms
  3. PMID 35479740 · Okabe 2022 · NMN 250 mg/day · blood NAD+ ~doubled by week 4, maintained through week 12
  4. PMID 36740954 · Pencina 2023 · NMN pharmacokinetic/NAD+ elevation RCT
  5. PMID 39116016 · Zhang 2025 · Crit Rev Food Sci Nutr · NMN dose-response meta-analysis · 12 RCTs n=513 · favorable glucose/lipid surrogate shifts
  6. PMID 35927255 · Igarashi 2022 · NMN 250 mg/day, 12 wk · walking speed (p=0.033) and left-hand grip strength (p=0.019) improved in older men
  7. PMID 35215405 · Kim 2022 · NMN 250 mg/day, 12 wk · afternoon-dosing-specific sleep/fatigue/sit-to-stand improvement in older adults
  8. PMID 34238308 · Liao 2021 · J Int Soc Sports Nutr · NMN 600–1200 mg/day, 6 wk · dose-dependent aerobic-capacity (ventilatory threshold) gain in amateur runners
  9. PMID 36797393 · Katayoshi 2023 · NMN 250 mg/day, 12 wk · brachial-ankle pulse-wave velocity trend non-significant (honest null)
  10. PMID 36002548 · Fukamizu 2022 · NMN safety to 1250 mg/day for 4 weeks
  11. PMID 34578794 · Zhou 2021 · astaxanthin skin meta-analysis · skin moisture (SMD 0.49, p<0.001) and elasticity (SMD 0.46, p<0.05) significant
  12. PMID 38243785 · Liu 2024 · astaxanthin fatigue/motor-function meta-analysis · fatigue and motor function significant; cognition signal directional/non-significant
  13. PMID 32755613 · Xia 2020 · astaxanthin cardiovascular meta-analysis · HDL-C significant · BMI/body-weight null
  14. PMID 18467083 · Kupcinskas 2008 · astaxanthin 40 mg/day, 12 wk · acceptable safety
  15. PMID 27552971 · Bonkowski & Sinclair 2016 · Nat Rev Mol Cell Biol · NAD+ and sirtuin-activating-compound mechanism review (no human lifespan endpoint)
  16. PMID 25786262 · Yurko-Mauro 2015 · PLoS One · DHA episodic-memory SR+MA in older adults with mild cognitive complaint (cross-link context)
  17. PMID 26978738 · Mocking 2016 · Transl Psychiatry · EPA-predominant omega-3 depressive-symptom MA-regression (cross-link context)
  18. PMID 28202713 · Martineau 2017 · BMJ · vitamin D3 acute-respiratory-infection IPD meta, deficient subgroups (cross-link context)

Coverage Notes

This Longevity Stack page draws from five linked ingredient pages: astaxanthin, nmn, spermidine, resveratrol, and urolithin A. NMN and astaxanthin carry full PMID-cited human-trial evidence; spermidine, resveratrol, and urolithin A have strong preclinical mechanism literature but limited clinical-endpoint translation, so this page describes their longevity evidence qualitatively as preliminary / emerging in the evidence stack and treats them as mechanism candidates in How It Works and Stacking & Timeline rather than fabricating PMID citations that do not yet exist. Transparency note: a frequently circulated "Mehmel 2020" urolithin A older-adult RCT does not return a verifiable PubMed record under that author and title and is therefore not cited here.

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