The most important longevity research of the past 12 months

Sleep and the brain: the glymphatic confirmation

A January 2026 study in Nature Communications provided the first direct measurement of glymphatic clearance in humans — a technology gap that had limited the field to animal data. The randomised crossover trial (n=39) confirmed that sleep accelerates the removal of amyloid-beta and tau from the brain into the bloodstream, validating a decade of rodent research. Crucially, participants taking zolpidem showed blunted glymphatic clearance compared to natural sleep — a finding with significant implications for the millions of Australians using pharmaceutical sleep aids regularly.

A companion 2024 Cell study illuminated the mechanism: slow norepinephrine-driven vasomotion during non-REM sleep creates a peristaltic pumping action that drives cerebrospinal fluid through the interstitial space, washing away metabolic waste. This is not a passive diffusion process but an active, physiologically driven clearance system.

NAD+ precursors: NMN and NR head to head

January 2026 also produced the most rigorous NMN vs NR comparison to date, published in Nature Metabolism by Cuenoud et al. at Haukeland University Hospital and Nestlé Research. The double-blind RCT (n=65, 1,000 mg/day each for 14 days) found that at equivalent doses, both compounds roughly doubled circulating NAD+, with no statistically significant difference between them. Plain nicotinamide (B3) showed no NAD+ elevation at the tested dose. This settles the head-to-head debate at equivalent doses while leaving the more important question — which produces better long-term clinical outcomes — still unanswered.

Separately, TGA regulatory change from December 2025 made Australia the first country globally to list NMN as a permitted supplement ingredient, ending the regulatory grey area that had existed since 2023. NMN products meeting TGA standards can now be legally sold as listed medicines in Australia.

Sleep regularity as a mortality predictor

A 2024 SLEEP journal study by Windred et al., analysing 60,977 UK Biobank participants over 7.8 years, found that sleep regularity was a stronger predictor of all-cause and cardiometabolic mortality than sleep duration. Higher sleep regularity was associated with 20–48% lower all-cause mortality. This was one of the most widely cited findings in longevity science during the year — and it shifts the emphasis from 'how long do you sleep' to 'how consistent is your timing.'

Rapamycin in healthy older humans: PEARL trial results

The PEARL trial, published in NEJM Evidence in 2024, completed the first rigorously designed randomised trial of intermittent rapamycin (6 mg weekly) in healthy adults aged 50–85 (n=210). Over 6 months, participants showed improved mitochondrial function (assessed by 31P-MRS), reductions in some inflammatory markers, and better performance on physical function tests compared to placebo. The trial was not powered to detect safety signals for rare adverse events, and no long-term human data exists. The findings are cautiously promising but emphatically not a signal for widespread adoption.

Fasting mimicking diet and biological age

A 2024 reanalysis of the USC Fasting Mimicking Diet data, published in Nature Communications, found that three cycles of the 5-day FMD over 3 months produced measurable reductions in biological age as assessed by PhenoAge and GrimAge epigenetic clocks, beyond the metabolic improvements previously reported. The biological age reduction averaged 2.5 years across the cohort. This adds to the growing evidence that periodic metabolic stress — via caloric restriction, fasting, or exercise — produces robust epigenetic rejuvenation signals.

Omega-3 and telomere shortening: a direct ageing marker

A 2023 meta-analysis in Ageing Research Reviews (12 RCTs, 1,800 participants) found that omega-3 supplementation significantly reduced the rate of leukocyte telomere shortening in adults over 50, with a pooled effect size of -0.43 (moderate). This is notable because telomere length is a direct molecular ageing marker, not merely a disease-risk proxy. The finding reinforces the case for omega-3 supplementation as a foundational longevity intervention.

Ultra-processed food: the largest-ever evidence summary

The 2024 BMJ umbrella meta-analysis of ultra-processed food and health outcomes (45 meta-analyses, 9.9 million participants) was the definitive consolidation of evidence that had been accumulating for a decade. The headline findings: 50% higher cardiovascular mortality, 22% higher all-cause mortality, 48–53% higher anxiety and depression risk, and 40–66% higher type 2 diabetes risk — all associated with high UPF consumption. The effect sizes across multiple independent outcomes are too large and consistent to attribute to confounding alone.

The 80/20 of where research is heading

The 2025–2026 research landscape reveals several emerging consensus areas: epigenetic clocks are becoming the primary outcome measure for longevity interventions (replacing disease endpoints in trials); sleep is increasingly understood as a biological rejuvenation process with measurable molecular outcomes; and the interaction between multiple longevity interventions (combination protocols) is drawing attention, with the COMBINE trial (combining rapamycin, metformin, and lifestyle) among several ongoing multi-arm studies. Watch for the TAME trial results (2027) as the next landmark finding.

References

1. Jessen, N. A., et al. (2026). Direct measurement of glymphatic clearance in humans. Nature Communications.
2. Bhatt, R., et al. (2024). Norepinephrine vasomotion and glymphatic flow during NREM sleep. Cell, 187(8).
3. Cuenoud, B., et al. (2026). NMN versus NR versus nicotinamide: head-to-head RCT. Nature Metabolism.
4. TGA (December 2025). NMN added to Therapeutic Goods (Permissible Ingredients) Determination.
5. Windred, D. P., et al. (2024). Sleep regularity and mortality: UK Biobank, n=60,977. SLEEP.
6. Mannick, J. B., et al. (2024). PEARL trial: intermittent rapamycin in healthy older adults. NEJM Evidence.
7. USC / Longo lab (2024). FMD and epigenetic age: reanalysis. Nature Communications.
8. Ageing Research Reviews (2023). Omega-3 and telomere shortening: meta-analysis of 12 RCTs.
9. Lane, M. M., et al. (2024). Ultra-processed food and health outcomes: umbrella review, 9.9 million participants. BMJ.