Adjuncts — Urolithin A, Spermidine, Taurine, Glycine
The second tier
Beyond rapamycin + metformin + NAD+ precursors + senolytics, there's a tier of compounds with interesting human-relevant data and better safety profiles. None are silver bullets, but they're low-downside additions to a considered stack.
Urolithin A — mitophagy
Urolithin A is a metabolite your gut bacteria make from pomegranate + berries — but only 30–40% of people have the right microbes to produce it. Direct supplementation (branded MitoPure, 500–1000 mg/day) triggers mitophagy and has shown improvements in muscle function + strength in aged humans.
Spermidine — autophagy
Spermidine (in aged cheese, wheat germ, soybeans) induces autophagy. Higher dietary intake is associated with reduced cardiovascular mortality in large cohorts. Supplemental 1–3 mg/day is well-tolerated and is one of the cleanest autophagy-triggering supplements available.
Taurine — new 2023 signal
A landmark 2023 Science paper showed taurine deficiency is a driver of aging in mice, worms, and possibly humans. Taurine levels fall ~80% between age 5 and 60. Supplementing in aged mice extended lifespan by 10–12% and improved function. Human supplementation is generally safe at 2–6 g/day.
Glycine — the sleep + methylation bonus
Glycine (3 g before bed) improves sleep onset + quality in multiple trials. It also donates methyl groups for methylation-clock chemistry. In animal models, glycine supplementation modestly extends lifespan. Cheap, safe, and pairs well with magnesium for a sleep stack.
Key Takeaway
Urolithin A, spermidine, taurine, glycine — all four have meaningful evidence + low downside. None will change your life alone, but stacked thoughtfully they cover complementary longevity mechanisms (mitophagy, autophagy, cellular turnover, methylation). Cheaper than most peptides, safer than most drugs.