David A. Sinclair

David A. Sinclair is an Australian-American biologist at Harvard whose Lifespan presents his information theory of ageing and argues that ageing itself is a disease we can treat.

David Sinclair is a professor of genetics at Harvard Medical School and one of the world’s most prominent researchers in the biology of ageing. His laboratory has focused on sirtuins, NAD+, and the epigenetic regulation of ageing — work that has attracted enormous funding and media attention. Lifespan, published in 2019 and co-written with Matthew LaPlante, presents Sinclair’s “information theory of ageing”: the idea that ageing results from the loss of epigenetic information in cells, and that this process may be reversible.

The book is ambitious and often genuinely exciting — Sinclair writes with conviction about what he sees as one of the most important reframings in the history of medicine. He makes the case that ageing is not an inevitable biological process but a disease, one we should work to treat and potentially cure. The personal interventions he discloses — resveratrol, NMN, metformin, intermittent fasting, minimal red meat — have generated enormous popular interest and significant skepticism from other scientists who feel he advocates for lifestyle changes and supplements ahead of the evidence.

Sinclair’s critics, including fellow longevity researchers, have argued that he sometimes moves faster from laboratory findings to personal recommendations than the data supports, and that the book blurs the line between scientist and advocate. These criticisms are worth taking seriously. Lifespan is at its best as a lucid introduction to the biology of ageing and a compelling argument for treating it as a medical problem; it is more speculative as a personal guide to living longer. It is essential reading for anyone seriously interested in the field, with appropriate critical engagement.