In June, Science reported that circulating taurine does not decline with age in humans, monkeys or mice, undercutting the premise of a supplement boom that started with a 2023 mouse paper. Today Aging Cell adds the human functional data. In 137 men aged 20 to 93 — 49 inactive, 88 physically active — circulating taurine was not associated with age, muscle mass, strength, physical performance or mitochondrial function. The authors' reasoning is the right one: if taurine deficiency drove human aging, taurine should fall across adulthood and track the things that decline with it. It did neither.
Why this paper matters more than its size. It is small and it is men only, and both limits are real. But it measured the outcomes people actually buy taurine for — strength, performance, muscle — rather than a blood level, and it found nothing. It also notes an older human study in which a week of supplementation did not raise muscle taurine at all. The 2023 paper's human evidence, the authors observe, leaned on people under 20 and lacked anyone over 65. The supplement was sold to people over 65.
Loree’s takeThis is what evidence for a supplement would have to look like: a human study measuring the thing you care about. Here is one, and it is null. When a patient asks me whether to keep taking taurine, I do not argue mechanism. I ask what human outcome it has moved. Two papers this summer say: none that we can find.
Ben’s takeIt is August. The 2023 paper has produced two full years of revenue for a category that today's paper says has no human outcome behind it. Nobody refunds the supplement; nobody recalls the podcast episodes. The business was never in the second paper. It was never going to be.
Before buying a supplement, ask what human outcome it has moved. A "level" is not an outcome.