How can I estimate and extend my lifespan?

It depends on which factors matter most for you. Sleep, exercise, diet, smoking, alcohol, and blood pressure each shift life expectancy differently. A free quiz can estimate your lifespan and biological age in about 5 minutes, then show which habit would add the most years. YapSpan uses published study figures so you can see exactly where each estimate comes from.

What is biological age?

Biological age is an estimate of how old your body acts based on health markers and lifestyle habits, as opposed to your chronological age (years since birth). Someone with healthy habits may have a biological age younger than their birthday age.

YapSpan

GABA

From the YapSpan Longevity Wiki · Updated 2026-09-28

Test yourself: Sleep quiz10 questions · ~2 minStart →

Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the brain (the chemical messenger that most dampens nerve activity); as an oral supplement it is studied for stress and sleep.

Educational only, not a recommendation to take anything. YapSpan estimates are for reflection and entertainment only. They are not medical advice, a diagnosis, or a prediction of any individual outcome. Check with a doctor before making any medical decision.

Gamma-aminobutyric acid (GABA) is a non-proteinogenic amino acid and the main inhibitory neurotransmitter in the mammalian brain [1]. It acts on ionotropic GABA-A and metabotropic GABA-B receptors; the GABA-A receptor is also the target of benzodiazepines, apigenin and the valerenic acid in valerian. For an oral supplement the central question is whether swallowed GABA reaches the brain. It has long been thought unable to cross the blood-brain barrier, but studies of the question are contradictory and use widely differing methods. Any real effect of GABA supplements on brain and behaviour could come either from passage across the barrier or indirectly through the enteric nervous system of the gut, and the mechanism of action is regarded as unclear. Magnetic resonance spectroscopy of brain GABA after oral doses has been proposed to settle the question [2].

Test yourself: Sleep quiz10 questions · ~2 minStart →

In a randomised, double-blind, placebo-controlled trial, 40 adults with insomnia symptoms were assigned to 300 mg a day of GABA extracted from fermented unpolished rice germ (30 participants) or placebo (10 participants) for 4 weeks, with polysomnography before and after. In the GABA group, sleep latency fell from 13.4 plus or minus 15.7 minutes to 5.7 plus or minus 6.2 minutes (p = 0.001) and sleep efficiency rose from 79.4% to 86.1% (p = 0.018); these changes were seen only in the GABA group. Adverse events occurred in 4 participants (10%) [3]. A 2020 systematic review of 14 placebo-controlled human trials of natural or fermentation-derived oral GABA found mixed results, with limited evidence for effects on stress and very limited evidence for effects on sleep [1].

The rice-germ trial was small, allocated three participants to GABA for every one to placebo, leaving only 10 on placebo, and its reported improvements were changes within the GABA group [3]. Much of the evidence for a calming effect of GABA supplements was reported by researchers with a potential conflict of interest [2]. The trial result and the uncertainty over brain entry have not been reconciled, so the route by which oral GABA could affect sleep remains unresolved [2, 1].

Categories: Supplements|Sleep|Dietary supplements|Longevity Wiki

Related deep dives and quizzes

Deep dive: The 8 things that matter most for your sleep
Deep dive: What matters most for high-quality sleep
Quiz: Sleep quiz
Charts: What Matters charts
Quizzes: All quizzes

Longevity posts, plain English

Occasional notes when we publish: what the studies say, without hype. Unsubscribe anytime.

YapSpan estimates are for reflection and entertainment only. They are not medical advice, a diagnosis, or a prediction of any individual outcome. Check with a doctor before making any medical decision.

Biological mechanism

Evidence for sleep and insomnia

Evidence limitations

Doses used in studies

See also

Pages that link here

Link graph

References

Related deep dives and quizzes

Longevity posts, plain English