The longevity compounds, and how strong the evidence really is

Most supplement marketing collapses a messy evidence landscape into a single confident claim. This library does the opposite: for each target, we start from the compound with the strongest peer-reviewed base, then state plainly how strong that base actually is — and link the papers so you can check the work.

A note on reading the evidence. The strongest data for most of these compounds comes from trials in people or in mice, often in aging or clinical-oncology contexts. Dogs and cats are neither. We cite that literature to explain mechanism and evidence stage — never to imply that a finding in one species transfers cleanly to another, and never to suggest any of these compounds treats a disease. Nothing on this site is veterinary advice.

Longevity compounds

Rapamycin — the one that started it all

No compound in this library carries more weight. Rapamycin inhibits mTOR, the nutrient-sensing pathway that decides whether a cell spends its energy growing or repairing itself. Dial mTOR down and cells shift toward autophagy and maintenance.

In 2009 the NIA Interventions Testing Program showed that rapamycin, started at 600 days of age — the rough equivalent of a 60-year-old human — extended lifespan in mice, replicated across three independent laboratories (Harrison et al., Nature, 2009). It remains the single most robust pharmacological lifespan result in mammals.

What makes it relevant here is that it did not stop at mice. A randomized, placebo-controlled trial in 24 middle-aged pet dogs found ten weeks of low-dose rapamycin well tolerated, with improvements in age-associated measures of heart function (Urfer et al., GeroScience, 2017). The much larger TRIAD trial is now running, and it has not reported.

The crucial distinction — the one most coverage gets wrong — is dose. Daily high-dose rapamycin suppresses the immune system; that is how it is used in transplant medicine. Low, intermittent dosing appears to do something closer to the opposite, improving immune function in older adults (Mannick et al., Science Translational Medicine, 2014). Same molecule, different pharmacology.

Rapamycin is a prescription drug, not a supplement. It is not something to source on your own, and the dose is not something to guess at. Read the full study library, then talk to a veterinarian.

Urolithin A — strong human evidence

Urolithin A is a gut-microbiome metabolite of ellagitannins (from pomegranate, walnuts, and berries). Its defining action is mitophagy: the selective recycling of damaged mitochondria. In the first-in-human trial, single and 4-week repeated oral doses of 250–1000 mg were safe and shifted plasma acylcarnitines plus skeletal-muscle mitochondrial gene expression toward a healthier signature (Andreux et al., Nature Metabolism, 2019). A later randomized, placebo-controlled trial in middle-aged adults reported roughly a 12% improvement in muscle strength over four months alongside lower C-reactive protein (Singh et al., Cell Reports Medicine, 2022). Replicated randomized data is rare in this category; urolithin A has it. It supports mitochondrial health and muscle function.

Calcium alpha-ketoglutarate (Ca-AKG) — animal-model evidence

Alpha-ketoglutarate is an endogenous intermediate of the citric-acid (Krebs) cycle and a cofactor in epigenetic regulation. Late-life dietary Ca-AKG extended lifespan and compressed morbidity in aging mice, with reduced frailty and lower systemic inflammatory cytokines — notably when started in middle age (Asadi Shahmirzadi et al., Cell Metabolism, 2020). The human data is not there yet, and we grade it accordingly. It supports cellular energy metabolism.

Spermidine — emerging evidence

Spermidine is a naturally occurring polyamine and a well-characterized inducer of autophagy, the cell's self-cleaning pathway. Human cognition results are genuinely mixed: a small three-month trial in older adults at risk for dementia reported improved memory performance (Wirth et al., 2018), while the larger, more rigorous SmartAge randomized trial did not confirm a cognitive benefit (Schwarz et al., SmartAge protocol, Alzheimer's Research & Therapy, 2019). Compelling mechanism, unsettled outcomes — "emerging," not "proven." It supports cellular renewal.

Fisetin — early evidence

Fisetin is a plant flavonoid and, of ten flavonoids screened, the most potent senolytic — it selectively clears senescent ("zombie") cells. Intermittent late-life dosing reduced senescence markers across tissues and extended median and maximum lifespan in mice (Yousefzadeh et al., EBioMedicine, 2018). The preclinical story is strong; human trials are still early and small. It supports healthy aging and cellular balance.

Resveratrol — emerging evidence

Resveratrol is a stilbenoid that engages cellular-energy pathways. The honest caveat is bioavailability: absorption is high but first-pass metabolism is so extensive that oral bioavailability is well under 1% (Walle et al., Drug Metabolism and Disposition, 2004). That is exactly why formulation and dose matter, and why we treat it as antioxidant support rather than a headline actor.

Immune compounds

Turkey tail (PSP/PSK) — strong human evidence

Turkey tail (Trametes versicolor) yields two protein-bound polysaccharides, PSP and PSK. PSK (Krestin) has been used as a clinical adjuvant in Japan since 1977, and mechanistically acts as a selective TLR2 agonist that activates dendritic cells, CD8⁺ T cells, and natural-killer cells (Lu et al., PNAS, 2011; see also the NCI Medicinal Mushrooms PDQ review). We cite this to explain the immune-cell mechanism; the pet claim is structure/function only: it supports the normal function of immune cells.

Reishi — emerging evidence

Reishi (Ganoderma lucidum) β-glucans modulate immune signaling toward balance. A randomized controlled trial in healthy adults found reishi β-glucan produced statistically significant shifts in CD3⁺/CD4⁺/CD8⁺ lymphocytes and NK cells versus placebo (Foods, 2023). Promising and human, but early — emerging. It supports immune-system balance.

Curcumin (BCM-95) — emerging evidence

Curcumin helps balance inflammatory-signaling pathways, but plain curcumin is poorly absorbed. We use the BCM-95 form, which combines curcuminoids with turmeric essential oils; a crossover pharmacokinetic study found roughly 7-fold higher relative bioavailability than standard curcumin (Antony et al., 2008). It supports a healthy inflammatory response.

Why this matters

Put the shelf together and a pattern appears. The strongest evidence is usually human or murine, and it is thinnest exactly where pet owners need it most — in dogs and cats themselves. That gap is not a reason to give up on the science. It is a reason to read it carefully, grade it honestly, and refuse to let confidence outrun the citations.

Read on: Rapamycin in depth, Urolithin A, why one science base serves both species, or browse the full study library.

References

1. Andreux P.A. et al. The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nature Metabolism, 2019. Link
2. Singh A. et al. Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health. Cell Reports Medicine, 2022. Link
3. Asadi Shahmirzadi A. et al. Alpha-ketoglutarate extends lifespan and compresses morbidity in aging mice. Cell Metabolism, 2020. Link
4. Wirth M. et al. The effect of spermidine on memory performance in older adults at risk for dementia. 2018. Link
5. Schwarz C. et al. Spermidine supplementation in subjective cognitive decline (SmartAge). Alzheimer's Research & Therapy, 2019. Link
6. Yousefzadeh M.J. et al. Fisetin is a senotherapeutic that extends health and lifespan. EBioMedicine, 2018. Link
7. Walle T. et al. High absorption but very low bioavailability of oral resveratrol in humans. Drug Metabolism and Disposition, 2004. Link
8. Lu H. et al. Polysaccharide Krestin is a novel TLR2 agonist that stimulates CD8 T cells and NK cells. PNAS, 2011. Link
9. National Cancer Institute. Medicinal Mushrooms (PDQ) — Health Professional Version. Link
10. Evaluation of immune modulation by β-glucan from Ganoderma lucidum: a randomized controlled trial. Foods, 2023. Link
11. Antony B. et al. A pilot cross-over study to evaluate human oral bioavailability of BCM-95CG (Biocurcumax). 2008. Link