Benefits
Mitochondrial Health Support (via Urolithin A)
Urolithin A, the only component of the blend with human trial data, is thought to support mitochondrial health by promoting mitophagy. Trials of urolithin A on its own reported improved markers of mitochondrial function, and that is the rationale for Sabrolithin A&B. The picture is mixed though: in the 2022 trial in 66 older adults, maximal ATP production in the hand muscle did not improve significantly, and the blend itself has never been tested.
Muscle Endurance and Strength (via Urolithin A)
Two trials of urolithin A, one over 4 months in middle-aged adults and one in 66 older adults, reported better muscle strength and better muscle endurance than placebo. Honest context: these results are for urolithin A specifically, not the A+B combination, and the older-adult trial missed its own primary endpoints. Its authors report that 6-minute walk distance and maximal ATP production in the hand muscle were both non-significant, so the endurance improvement was a secondary finding.
Mitophagy Activation
Urolithin A is one of the better studied compounds thought to trigger mitophagy, the cellular process that clears damaged mitochondria. In people this has only been measured indirectly, as changes in gene expression and blood markers, not as mitophagy itself. It is the reasoning behind the product's longevity and muscle positioning rather than a proven consumer outcome.
Bypasses Gut-Conversion Variability
Only a minority of people efficiently convert dietary ellagitannins into urolithins. Supplying preformed urolithins directly is intended to bypass this individual variability. No cited trial compared Sabrolithin A&B with pomegranate or walnut intake, so this is a sensible rationale rather than a demonstrated advantage.
Emerging Urolithin B Interest (Preliminary)
Urolithin B has shown effects on muscle-protein pathways in preclinical models, prompting interest in combining it with urolithin A. Honest context: robust human evidence for urolithin B is lacking, so its contribution remains speculative.
Mechanism of action
Mitophagy Induction (Urolithin A)
Urolithin A activates mitophagy by upregulating pathways that tag and clear dysfunctional mitochondria, supporting renewal of the mitochondrial pool — the best-characterized mechanism in the urolithin family.
Mitochondrial Biogenesis Support
Beyond clearing damaged mitochondria, urolithin A has been reported in laboratory work to support mitochondrial biogenesis signaling, the making of new mitochondria. None of the cited human trials measured new mitochondria being built in muscle, so treat this as a proposed mechanism.
Urolithin B Anabolic Signaling (Preclinical)
Urolithin B has been reported in preclinical models to influence muscle-protein synthesis and degradation pathways. This mechanism is the rationale for the A+B blend but has not been confirmed in rigorous human trials.
Clinical trials
First-in-human randomized, double-blind, placebo-controlled study of direct urolithin A (single and 4-week multiple doses up to 1,000 mg/day) in healthy, sedentary older adults.
Healthy sedentary elderly adults.
Urolithin A was safe and absorbed well, and produced changes in blood and muscle markers that the authors describe as a molecular signature of improved mitochondrial and cellular health. This was a first-in-human safety and biomarker study, not a test of strength, endurance or anything a person would notice, and it used urolithin A alone rather than the Sabrolithin A&B blend.
Randomized, double-blind, placebo-controlled trial of direct urolithin A (500 mg and 1,000 mg/day) over 4 months in middle-aged adults, assessing muscle strength, exercise performance, and mitochondrial biomarkers.
Middle-aged adults.
Urolithin A improved muscle strength and biomarkers of mitochondrial health compared with placebo. This is the cleanest positive result in the file. Two caveats: it tested urolithin A alone, not the A+B blend, and all three trials cited on this page share several of the same authors, so the evidence base has not been reproduced by an independent group.
Randomized clinical trial of direct urolithin A (1,000 mg/day) versus placebo in older adults, evaluating muscle endurance and mitochondrial health.
66 older adults.
Important: this trial did not meet its primary endpoints. Its authors report that the improvements in 6-minute walk distance and in maximal ATP production in the hand muscle were not significant. Muscle endurance in the hand and leg muscles did improve versus placebo, but as a secondary finding rather than the trial's main test. And the evidence is for urolithin A specifically; human data on an A+B combination remain thin.