How to Read a Longevity Study Without Losing Your Mind

Most longevity headlines are wrong in the same three ways. The study was in mice, the effect size was modest, and the press release removed every caveat the authors put in the abstract. If you learn to check those three things first, you will save yourself years of hype cycles.

Start with the organism. Yeast, worms, flies, mice, humans — each rung of that ladder discards more of what came before. A yeast finding is a hypothesis. A mouse finding is a lead. A human RCT is a result. Rapamycin is unusual because it has real signal at multiple rungs; most compounds do not.

Next, the effect size. A 10 percent median lifespan extension in mice is enormous. A statistically significant but clinically tiny change in a biomarker is not. Learn to read confidence intervals; they will tell you more than the headline ever will.

Finally, the caveats. Read the discussion section. The authors almost always tell you what they think their study does not prove. That paragraph is where the real science lives.