Taurine doesn't decline with age after all. Two years, one supplement boom, one correction.

In June 2023, Science published a paper reporting that circulating taurine — an amino acid, best known as an energy-drink ingredient — falls with age, and that supplementing it extended lifespan in worms and mice and improved health markers in monkeys. Within months taurine was a longevity supplement. Today, in the same journal, scientists at the National Institute on Aging report that in humans followed for years in the Baltimore Longitudinal Study of Aging, in rhesus monkeys and in mice, taurine levels rose or stayed flat with age. The variation between two people of the same age, and within one person over time, was larger than any change with age at all.

What this does and doesn't say. It does not say taurine is useless, and the authors are careful about that. It says the premise of the supplement — that you are low and getting lower — does not hold in healthy people, and that taurine is unlikely to be a useful marker of aging. The 2023 human data had a known weakness: its age trend was driven by the young end of the sample and it lacked people over 65. The NIA cohort runs from 26 to 100. The institute's own summary is blunter than the paper: there is no solid clinical data showing that supplementation benefits humans. Seafood and meat are where the dietary taurine is; a normal diet supplies it.

Loree’s take

This is the evidence hierarchy doing its job in public. Worm and mouse lifespan, a mechanism that sounds right, one human cross-section with a gap at the old end — that is where the 2023 paper sat, and it was treated as a human finding because the headline was good. The correction took two years, which is fast. The patients who started taurine in 2023 did not get those two years back.

Ben’s take

Between the first paper and the second, a product category was born, funded and sold. That is the business model: it needs the first paper and never needs the second, because a correction does not come with refunds. The supplement is still on the shelf tonight. The press release about today's paper will not be on the label.

Why it matters to a recovering optimizer. Taurine is a clean specimen of how a longevity supplement is made: one impressive animal paper, a plausible story, an existing cheap molecule, a market that moves faster than replication. The defense is not to be cynical about science — the two papers together are science working. It is to wait for the second paper before you buy, and to notice how rarely the industry does.