About the Journal
A working notebook on what we know, and what we don't.
RappinAboutRapa is written by Gregg Davison — a former student biologist, former paramedic, professional speaker, and relentlessly curious student of longevity science. Rapa-curious for 14 years, searching for a willing prescriber for two, and an intermittent rapamycin user for seven, Gregg writes for curious readers who want to understand rapamycin and longevity science without the hype, the jargon, or the sales pitch.
I write about rapamycin, mTOR biology, and the science of aging for readers who want the story as it actually is — not the marketing version, not the doomer version, and not the version optimized for a headline. You do not need a medical degree to read along. You just need curiosity and a little patience for the unknown.
My starting assumptions are simple. The mouse data on rapamycin is unusually strong. The human data is unusually thin. Anyone claiming certainty in that gap is telling you more about themselves than about the drug.
Four commitments
Curiosity. I take unglamorous questions seriously — dosing schedules, biomarkers that don't quite correlate, side effect profiles in the wild.
Humility. When the evidence changes, so does the writing. Corrections live at the top of the piece, not in a footnote nobody reads.
Storytelling. Science is a human process. I follow the data, but I also tell the story of how we got it, what it means, and what still puzzles us.
Evidence. Every meaningful claim links back to the paper. If the paper is behind a paywall, I say so. If the claim is mine and speculative, I say that too.
Independent labs replicating rapamycin lifespan extension in mice (ITP)
Approximate median lifespan extension in male mice, ITP data
Adequately powered human RCTs on healthspan outcomes to date
Trials Worth Watching
The human evidence, slowly arriving.
PEARL — the first randomized trial of rapamycin for healthspan
The PEARL trial (Participatory Evaluation of Aging with Rapamycin for Longevity) is the first randomized, double-blind, placebo-controlled study of intermittent low-dose rapamycin in healthy adults. Roughly 130 participants took 5 mg or 10 mg weekly for twelve months, with body composition, physical function, and quality-of-life measures tracked throughout. Results published in 2024 reported improvements in lean muscle mass and pain in women in the higher-dose group, with no serious adverse events. The effect sizes are modest and the sample is small — but PEARL is the first time we have human outcome data on this question at all, and that matters.
The University of Arizona study — coming next
A team at the University of Arizona is preparing a larger, longer trial of rapamycin in older adults, building on what PEARL began: more participants, additional biomarkers of immune and metabolic health, and an extended follow-up window. It won't answer every question — no single trial will — but it is the next honest step, and I'll be reading it carefully when the data lands.
REACH — rapamycin in mild cognitive impairment and early Alzheimer's
The REACH trial at the University of Texas Health Science Center at San Antonio is asking a different question: whether rapamycin can slow progression in people with amnestic mild cognitive impairment or early-stage Alzheimer's disease. This Phase 2 study is enrolling around 40 participants, randomizing them to daily rapamycin or placebo for a year while tracking cognition, daily function, and Alzheimer's biomarkers. The premise is grounded in mTOR biology and decades of animal work — not in a promise of a cure — which is exactly the kind of measured question that deserves careful human data.
The Dispatch
Careful reading, delivered once a fortnight.
New essays, papers worth your attention, and quiet reflections on what the rapamycin literature is — and is not — telling us. No hype. No sales.
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