Glycine supplementation extends lifespan of male and female mice.
Level 5 - mechanism / opinion, no new human data
Preclinical animal study in mice (CEBM Level 5).
PubMed 30916479 · doi:10.1111/acel.12953
What was done
Genetically heterogeneous mice were fed an 8% glycine diet across three independent test sites within the National Institute on Aging's Interventions Testing Program (ITP). Researchers evaluated total lifespan, maximum lifespan, body weight, and end-of-life pathology across 40 varieties of incidental lesions. Parallel cohorts tested TM5441 (a PAI-1 inhibitor), inulin, and aspirin (two doses).
What was found
Glycine supplementation produced a 4% to 6% increase in overall lifespan and extended maximum lifespan in both males (p = 0.002) and females (p < 0.001). When pooled across sexes, lifespan extension was observed at all three sites (p = 0.01, p = 0.053, and p = 0.03). Supplemented females were lighter than control females, while male weights remained unaffected. Glycine-treated mice showed lower mortality from pulmonary adenocarcinoma (p = 0.03) with no significant increase in any of the 40 incidental pathologies evaluated. Parallel tests of TM5441, inulin, and aspirin showed no lifespan benefits.
Why it matters
This study provides replicated, multi-site evidence that dietary amino acid modulation via glycine supplementation modestly extends median and maximum lifespan in rodents without obvious toxic pathology.
Limits
The abstract does not report the total sample size (n) or exact baseline/final lifespan durations in days. The findings are restricted to mice receiving a high-dose (8%) dietary formulation, and applicability, safety, and optimal dosing in humans remain unestablished.
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- supports High-dose glycine supplementation extends the lifespan of laboratory mice.