Interventions Testing Program

The Interventions Testing Program is a US government programme that tests candidate life-extending compounds in mice at three independent laboratories using one shared protocol. It was launched by the National Institute on Aging in 2004, and compounds are proposed by researchers from outside it.

Its design answers the usual objections to animal lifespan work before they are raised. Each candidate runs in parallel at the Jackson Laboratory, the University of Michigan and the University of Texas Health Science Center at San Antonio, which rules out a result that belongs to one facility. The mice are UM-HET3, a genetically heterogeneous stock, which greatly reduces the chance that a finding holds only for one inbred strain. Males and females are both tested, which turns out to matter: a 2025 review covering two decades found sex-specific responses to be one of the programme’s most consistent patterns.

The scale is worth knowing when reading any claim that a compound “extends lifespan in mice”. A 2017 update reported 53 lifespan experiments involving 30 agents over eleven years, with significant effects published for six of them. The 2025 review put the two-decade totals at 54 agents in more than 30,000 mice.

The programme has also become an unusually clear demonstration that analysis choices matter. In 2024, researchers reanalysed the programme’s data from 2004 to 2022 using the Gehan test rather than the log-rank test the published results were based on, and identified five further compounds — among them metformin and enalapril — whose effects the original test was too insensitive to detect.