Calcium alpha-ketoglutarate — Ca-AKG, sold as Rejuvant — is one of the more scientifically interesting longevity supplements, and also one where the headline outruns the evidence by the widest margin. The molecule is real and important; the “reverse your biological age by 8 years” claim rests on a much shakier study than the marketing admits.
What it is
Alpha-ketoglutarate (AKG, or 2-oxoglutarate) is a central intermediate of the citric-acid (TCA) cycle and a cofactor for a family of enzymes that includes the DNA-demethylases involved in epigenetic regulation. Endogenous AKG falls substantially with age, which is the rationale for supplementing the stable calcium salt. Unlike most longevity supplements, the “it declines, so restore it” logic here is grounded in real metabolism.
The animal evidence is genuinely interesting
The strongest data is preclinical. In aging mice, Ca-AKG started late in life produced a modest lifespan extension and — more strikingly — a compression of morbidity: the animals spent a larger share of their lives healthy and less frail, with the effect linked to reduced inflammation.[1] The mechanistic roots go back to worms, where AKG was shown to extend lifespan by inhibiting ATP synthase and the mTOR pathway.[2] “Healthier for longer,” not just “longer,” is an appealing and well-supported animal result.
| Claim | What the evidence supports |
|---|---|
| AKG declines with age | Yes — established metabolism |
| Extends lifespan / compresses morbidity | In mice and worms — not shown in humans |
| '~8 years younger' in people | Uncontrolled, industry-linked clock study only |
| Improves a hard human outcome | No RCT has shown this |
Safety
AKG is a normal metabolite and is generally well tolerated in the available human data; the calcium load is modest but worth noting if you already take a lot of calcium. As with the whole category, the open question is efficacy, not acute safety — long-term safety in healthy adults simply hasn’t been established by adequately powered trials.
The honest bottom line
Ca-AKG is one of the better mechanistic bets in longevity: a declining metabolite with real mouse data showing animals stay healthier longer.[1] But the human evidence is a single uncontrolled, industry-linked methylation-clock study, and a clock moving is not the same as aging slowing.[3] The fair verdict is “promising preclinical compound, marketing far ahead of the human data” — worth watching for a real randomized trial, not worth the “8 years younger” headline. Compare it with the other longevity compounds in our longevity evidence matrix, and see NAD⁺ precursors for a related decline-and-restore story with human biomarker data.