The first time I saw a longevity supplement claim to “reverse” eight years of aging, I rolled my eyes. Then I read the actual study, and the truth turned out to be more interesting (and more complicated) than either the hype merchants or the skeptics will admit. Calcium alpha-ketoglutarate, usually written CA-AKG or Ca-AKG, is one of the few longevity compounds with a real lifespan study behind it, and also one of the most overstated. Here is what the evidence actually says.

What is CA-AKG (calcium alpha-ketoglutarate)?

Calcium alpha-ketoglutarate (CA-AKG) is a calcium salt of alpha-ketoglutarate, a molecule your cells already make inside the Krebs cycle to produce energy. Marketed as a longevity supplement, it has extended lifespan in mice and shown early signs of lowering biological age in a small human study, but the human evidence remains preliminary.

Alpha-ketoglutarate is not some exotic lab invention. It sits right in the middle of the tricarboxylic acid (TCA) cycle, the metabolic engine that turns food into ATP in nearly every cell you own. It also feeds amino acid synthesis, regulates gene-controlling enzymes, and helps clear nitrogen waste. The “calcium” part is just a stable delivery format, the same reason you see calcium citrate or calcium ascorbate on labels.

Here is the hook that pulled researchers in: your natural AKG levels collapse as you age. One frequently cited estimate is that circulating AKG at age 80 is roughly 10% of what it was at 40 (Qidosha review of Ca-AKG evidence). That kind of steep age-related decline is exactly what makes a metabolite look like a longevity lever. The obvious question follows: if you put it back, does anything change?

Does calcium alpha-ketoglutarate actually extend lifespan?

In mice, yes, and the data are surprisingly clean. The landmark study came out of the Buck Institute and was published in Cell Metabolism in 2020. Researchers fed aging mice a diet containing 2% CA-AKG by weight, starting at 18 months of age (roughly late middle age for a mouse, which matters because it mimics a realistic human scenario where nobody starts supplements at birth).

The results, from the published paper in Cell Metabolism:

  • Female mice saw median lifespan extended by roughly 10 to 16% across cohorts.
  • Male mice showed a smaller, statistically weaker lifespan signal (around 9 to 13% median, not reaching significance for overall survival).
  • The frailty benefit was even bigger than the lifespan benefit. The period of late-life sickness, what scientists call morbidity, shrank by about 41 to 46%.

That last point is the part I find genuinely compelling, and it gets lost in headlines. The mice did not just live longer. They spent a much smaller slice of their lives frail, coat ungroomed, hunched, and sick. Researchers call this “compression of morbidity,” and arguably it matters more than raw lifespan. Nobody wants extra years if they are bedbound years.

The proposed mechanism is not magic. The team found that AKG nudged immune T cells to produce more interleukin-10 (IL-10), an anti-inflammatory signal, which in turn dampened the chronic, smoldering inflammation that drives so much of aging. The longevity world has a clunky nickname for that background inflammation: “inflammaging.” CA-AKG appears to cool it down.

What does the human evidence on CA-AKG show?

This is where you need to slow down and read carefully, because the gap between the mouse data and the human data is wide.

The headline human result comes from a 2021 study in the journal Aging on a branded timed-release CA-AKG product called Rejuvant. Across 42 people (average age 63), participants who took it for about seven months showed an average drop of roughly eight years in biological age, as measured by a DNA methylation “clock” (Rejuvant study in Aging). Forty of the 42 saw their biological age fall. The daily dose was 1 gram of CA-AKG plus a sex-specific vitamin.

Eight years sounds spectacular. So why am I not telling you to run out and buy it? Because the study authors themselves listed the catches, and they are big ones:

  • It was retrospective with no placebo group. People who already chose to buy and take a longevity supplement are not a neutral sample.
  • The sample was tiny: 42 self-selected, self-reported-healthy individuals.
  • It leaned on a single epigenetic clock and lacked clinical biomarkers or other aging-clock comparisons.
  • One author was a consultant and board member for the company selling the product.

None of that makes the result fake. It makes it a promising signal that has not yet been confirmed under the conditions that actually settle these questions. The authors said as much, calling for a placebo-controlled trial. That trial is now happening: the ABLE study is a randomized, double-blind, placebo-controlled trial testing CA-AKG against biological age in middle-aged adults. Until results like that land, treat the eight-years claim as a hypothesis wearing a press release.

Is CA-AKG safe, and is it FDA approved?

Let me be blunt about the regulatory status, because YMYL honesty matters here. CA-AKG is sold as a dietary supplement, not an approved drug. The FDA has not approved alpha-ketoglutarate to treat, prevent, or reverse aging or any disease. Aging is not even recognized as a treatable indication by the FDA. Alpha-ketoglutarate generally falls under “Generally Recognized As Safe” (GRAS) status for food use, but as WebMD notes, the FDA does not review these products for anti-aging effectiveness or verify that the bottle contains what the label claims.

On tolerability, the picture is reassuring but not bulletproof. Human studies, including longer-term use at doses around 4.5 grams per day, have reported no serious side effects, and doses up to 6 grams have been considered safe in research settings (Qidosha safety review). The most common complaints are mild and gut-related: nausea, loose stools, or an upset stomach, usually at higher doses. Typical supplement doses sit in the 1 to 2 gram per day range.

The realistic risks are less about the molecule and more about the market. Supplement quality varies wildly, claims outrun evidence, and “reverse your age” marketing preys on a very human fear. If you take medications, are pregnant or breastfeeding, or have a chronic condition, the molecule’s metabolic activity is a reason to talk to a clinician first, not to wing it.

Should you take CA-AKG for longevity?

Here is my honest insider read after going through the papers. CA-AKG is one of the more scientifically grounded entries in a field full of snake oil. It has a real, peer-reviewed mammalian lifespan study, a plausible anti-inflammatory mechanism, a clean safety record at sensible doses, and an ongoing placebo-controlled human trial. That puts it well ahead of most things on the longevity shelf.

But “ahead of the pack” is not the same as “proven.” The strongest human number, the eight-year reversal, comes from a study its own authors warned you not to over-read. The mouse benefits were also sex-skewed toward females, which we do not yet understand in people. If you are curious, the rational stance is modest expectations, a reputable third-party-tested brand, a sensible dose, and a clinician in the loop, not a belief that you have bought back a decade. For more on how cellular-signaling compounds get hyped versus proven, see our explainer on peptides explained and our broader guide to longevity supplements.

Frequently asked questions

What is the difference between AKG and CA-AKG?

AKG is the active molecule, alpha-ketoglutarate. CA-AKG is that molecule bound to calcium to make a stable, supplement-friendly powder. The calcium is mostly a delivery vehicle, not the active longevity ingredient.

How much CA-AKG do studies use?

The human Rejuvant study used 1 gram of CA-AKG daily, while other human safety research has gone up to 4.5 to 6 grams without serious side effects. Most commercial supplements suggest 1 to 2 grams per day. Higher doses raise the chance of mild stomach upset.

Does CA-AKG really reverse biological age by 8 years?

One small, retrospective, placebo-free study reported an average 8-year drop on a DNA methylation clock. That is an encouraging signal, not a settled fact. A randomized, placebo-controlled trial is underway to test whether the effect holds up.

Is CA-AKG approved by the FDA for anti-aging?

No. CA-AKG is sold as a dietary supplement. The FDA has not approved it to slow, treat, or reverse aging, and aging is not an FDA-recognized treatable condition.

Who should avoid CA-AKG?

Anyone pregnant or breastfeeding, people on medications, and those with chronic health conditions should consult a clinician before starting, since CA-AKG is metabolically active and supplement quality is not guaranteed.

Medical disclaimer: This article is for general information only and is not medical advice. CA-AKG is not an approved treatment for aging or any disease. Talk to a qualified healthcare professional before starting any supplement.