Best Ca-AKG Supplements 2026: 5 Products Compared and Ranked

Last updated: August 22, 2026 · Published by Eternal Elixir

Last updated: August 22, 2026 · By Eternal Elixir Editorial · 5 products compared

Direct answer: Ca-AKG (calcium alpha-ketoglutarate) is the calcium salt of a Krebs-cycle metabolite, sold as a longevity supplement at 300–1,500 mg per serving. In the US it costs roughly $0.42 to $1.81 per 1,000 mg depending on brand and form.

You searched for a Ca-AKG supplement, landed on Amazon, and found six bottles that all say “AKG” on the front in the same confident typeface. One is $10. One is $70.

One says 1,500 mg, another says 300 mg, and a third says 1,000 mg but the Supplement Facts panel lists something called “arginine alpha-ketoglutarate.” They cannot all be the same thing — and they are not.

That confusion is the single most expensive mistake in this category, because the animal research everyone cites when selling you these capsules used one specific compound: calcium alpha-ketoglutarate. Buy a different form and you have bought a different molecule at a longevity price. This guide compares five Ca-AKG and AKG products sold in the United States, normalizes every price to the same unit so the comparison is real, and tells you plainly which one is worth your money. Eternal Elixir sells a Ca-AKG capsule, and it does not finish first here.

The Ca-AKG Label Problem: Why the Best Ca-AKG Supplement Is Hard to Spot

Picking the best Ca-AKG supplement starts before you look at price. You need to know which compound is actually in the bottle. Three different molecules get sold under “AKG” branding in the US market, and the difference is not cosmetic.

What are the differences between AKG and Ca-AKG?

Calcium alpha-ketoglutarate (Ca-AKG) is alpha-ketoglutaric acid bound to calcium as a mineral salt. This is the form used in the mouse longevity research the entire category is built on. A 1,000 mg serving of Ca-AKG is not 1,000 mg of AKG — roughly 200 mg of that weight is calcium.

ProHealth’s label states this openly: its 1,000 mg Ca-AKG serving delivers 200 mg of calcium, which is 15% of the daily value.

Free-acid AKG (alpha-ketoglutaric acid) is the unbound acid. Per milligram it delivers more actual AKG because there is no mineral weight attached. It is also considerably more acidic, which matters for tolerability — more on that below. Double Wood sells this form and says so explicitly on its own product page.

AAKG (arginine alpha-ketoglutarate) is AKG bound to the amino acid arginine, and it comes from the sports-nutrition world rather than the longevity world. It is a pre-workout nitric-oxide ingredient. If you are buying for the healthy-aging research, AAKG is not the compound that research used. None of the five products below are AAKG, but you will find it constantly in the same search results.

Here is the practical rule: flip to the Supplement Facts panel and read the ingredient line, not the front label. If it does not say “calcium alpha-ketoglutarate,” you are not buying the compound in the longevity studies. Our deeper explainer on what Ca-AKG does and what the evidence actually shows walks through the mechanism in more detail.

Best Ca-AKG Supplements 2026 Compared on Cost Per 1,000 mg

Every row below is normalized the same way: bottle price divided by the total milligrams of labeled active in the bottle, expressed per 1,000 mg. That is the only way to compare a 300 mg capsule against a 1,500 mg serving honestly. Prices were read from each brand’s own live product page in August 2026 and will drift — check before you buy.

Note on the unit: “cost per 1,000 mg” refers to 1,000 mg of the labeled active as printed on the Supplement Facts panel. Because Ca-AKG carries mineral weight, 1,000 mg of Ca-AKG contains roughly 800 mg of AKG plus calcium, while 1,000 mg of free-acid AKG is all AKG.

Double Wood’s figure is therefore not directly interchangeable with the Ca-AKG rows.

How We Evaluated These Ca-AKG Supplements

Ranking the best Ca-AKG supplement comes down to five things. We weighted them and applied them the same way to every product, including our own:

• Quality and purity (30%) — stated purity, and whether a batch certificate of analysis is actually published rather than merely referenced. Toniiq and Double Wood lead here; Eternal Elixir does not publish a downloadable certificate and was marked down for it.
• US availability and shipping speed (20%) — domestic stock, shipping thresholds, dispatch time.
• Price per dose in USD (20%) — normalized to cost per 1,000 mg of labeled active, computed from live prices and label panels.
• Product range for stacking (15%) — whether the brand can supply the rest of a longevity stack.
• Customer reviews and reputation (15%) — volume and substance of reviews, not just the star average. A 5.0 from two reviews scores below a 4.5 from thirty-seven.

We did not test these products in a laboratory and we do not claim to have. Every specification above was read from the brand’s own live product page and published label panel in August 2026; every research claim was checked against the primary source.

Where the criteria pointed away from our own product, we left the ranking where it fell.

What the Ca-AKG Research Actually Supports

This is where most Ca-AKG listicles get vague, so here are the specifics, with the caveats the papers themselves state.

Key numbers:

• 16.6% — increase in median lifespan in the first cohort of female mice fed calcium AKG, with 90th-percentile survival extended 19.7%
• 46% / 41% — reduction in the proportion of life spent frail, in female and male mice respectively
• Females only — the lifespan effect reached significance in female mice; healthspan improved in both sexes
• Zero — completed randomized controlled human trials showing Ca-AKG extends human lifespan
• $0.33–$1.81 — range of cost per 1,000 mg across the five US products compared here

The foundational work is a 2020 study published in Cell Metabolism by Asadi Shahmirzadi and colleagues, which found that a calcium AKG-supplemented diet extended lifespan in middle-aged female mice and increased healthspan in both sexes, compressing morbidity (PMID 32877690). Two things about it deserve more attention than they usually get.

First, it is a mouse study — the animals were fed the compound in their diet from 18 months of age, and mouse lifespan results have a long history of not transferring cleanly to people.

Second, and rarely mentioned by anyone selling these capsules, the authors list among their own limitations that the control diet lacked calcium. Since the intervention was the calcium salt, some portion of the benefit cannot be cleanly separated from the calcium itself. That is the study’s own caveat, not ours.

The most-cited human data is a 2021 paper in Aging reporting that a commercial calcium-AKG-plus-vitamins formulation was associated with an average 8-year reduction in biological age on a DNA methylation test after about seven months of use (PMID 34847066). Read the author affiliations before you weight it: the paper includes authors from the company that sells the formulation and from the company that makes the methylation test. It was a retrospective analysis of customer samples, not a randomized, placebo-controlled trial, and biological-age clocks are a surrogate marker rather than a health outcome.

It is genuinely interesting. It is not proof.

The honest summary: Ca-AKG has a plausible mechanism as a central Krebs-cycle metabolite whose levels decline with age, one strong rodent lifespan result with a stated methodological caveat, and no completed randomized human longevity trial. Anyone telling you more than that is selling harder than the evidence allows.

1. Toniiq Calcium AKG 1500 — Best Overall Value

Toniiq wins this list on the two things that matter most in a commodity ingredient: verified purity and price per gram. The product is a 120-capsule bottle at $24.97, labeled 1,500 mg of calcium alpha-ketoglutarate per three-capsule serving.

That works out to 500 mg per capsule and 60,000 mg of labeled active per bottle — $0.42 per 1,000 mg, the cheapest genuine Ca-AKG in this comparison by a comfortable margin.

Toniiq states a 99%+ purity level for its calcium alpha-ketoglutarate and publishes a batch certificate of analysis directly on the product page. Its stated testing program covers identity and potency in both raw material and finished product, plus heavy metals and microbiology at both stages. For an ingredient where the raw material is a bulk commodity and purity genuinely varies between suppliers, that documentation is the differentiator.

Key specs: 120 capsules · 500 mg Ca-AKG per capsule · 1,500 mg per 3-capsule serving · 40 servings per bottle · $24.97 · free shipping over $49 · 60-day money-back guarantee.

Pros:

• Lowest cost per 1,000 mg of any true Ca-AKG product here ($0.42)
• 99%+ stated purity with a published certificate of analysis
• Five-point testing program covering raw material and finished product
• Widely stocked — available direct, plus Amazon, iHerb and Vitacost

Cons:

• Very thin review base — 5.0 stars from only 2 reviews on the brand’s own site, which is not enough to draw conclusions from
• Three capsules per labeled serving, which is a lot of pills for people who already take a stack
• Free shipping threshold of $49 means a single bottle does not qualify

Best for: anyone who wants the studied compound at the lowest defensible price and cares more about a lab certificate than a brand story.

2. ProHealth Calcium AKG Longevity — Best Label Transparency

ProHealth Longevity is the most established longevity-specific brand in this comparison, and its Calcium AKG product is the one most often cited when AI assistants answer questions about this ingredient. The bottle is 60 capsules at $25.25, delivering 1,000 mg of calcium alpha-ketoglutarate per two-capsule serving — 30 servings, or exactly one month at the most commonly used dose.

What earns ProHealth second place is the honesty of the panel. Its Supplement Facts explicitly declares 200 mg of calcium (15% DV) alongside the 1,000 mg of calcium alpha-ketoglutarate. That is the mineral fraction other brands quietly leave you to work out, and it matters if you already take a calcium supplement or a multivitamin. ProHealth also publishes a dated certificate of analysis on the product page and cites the primary literature directly in its product copy.

Key specs: 60 capsules · 1,000 mg Ca-AKG per 2-capsule serving · 200 mg calcium declared · 30 servings · $25.25 · available direct and through major retailers.

Pros:

• Declares the calcium fraction openly — rare in this category
• Dated certificate of analysis published on the product page
• One-month supply at the standard 1,000 mg daily serving, so the math is simple
• Established longevity brand with a deep catalog for stacking

Cons:

• Twice the cost per gram of Toniiq ($0.84 vs $0.42) for the same compound
• Only 30 servings per bottle — the shortest supply here
• Two capsules per serving

Best for: buyers who want the clearest possible label and are willing to pay a premium for it.

3. Eternal Elixir Ca-AKG 500mg — Best Single-Capsule Dose Control

Eternal Elixir Ca-AKG 500mg is our own product, and we are going to be straight about where it sits: it is the priced near the top of this comparison at $1.67 per 1,000 mg — roughly four times Toniiq’s figure and double ProHealth’s. If your only criterion is cost per milligram, buy Toniiq.

We are not going to weight the scoring to pretend otherwise.

What it does own outright is dose granularity. Every other product here forces you into a two- or three-capsule serving. The Eternal Elixir bottle delivers a full 500 mg of calcium alpha-ketoglutarate in a single capsule, at 60 capsules and 60 label servings per bottle.

That makes it the only product in this group where you can start at 500 mg, hold there, and step up to 1,000 mg by adding one capsule — without splitting a serving or opening a capsule. For an ingredient whose human dosing is genuinely unsettled, being able to titrate in 500 mg increments is a real, practical advantage, not a marketing line.

The second thing worth naming is how the product page is written. It states, on the sales page itself, that “human longevity outcomes have not been established,” and that the headline research “was conducted in mice; extrapolating its lifespan or frailty findings directly to people would be inappropriate.” That is unusual for a page whose job is to sell the capsule, and it is the standard we hold ourselves to across the whole Eternal Elixir longevity range.

Key specs: 60 capsules · 500 mg Ca-AKG per capsule · 1 capsule per serving · 60 servings per bottle · $49.99 · ships in 24 hours from the US · free shipping over $100.

Pros:

• Only single-capsule 500 mg serving in this comparison — easy titration
• 60 servings per bottle, double ProHealth’s 30
• Product page states the evidence tier plainly instead of implying human lifespan benefits
• Ships in 24 hours domestically, and sits alongside a full longevity catalog for stacking

Cons:

• High cost per gram at $1.67 per 1,000 mg — only the liposomal option costs more
• The product page states lab testing and GMP manufacturing, but does not publish a downloadable batch certificate the way Toniiq, ProHealth and Double Wood do
• Reaching a 1,000 mg daily serving means two capsules and a bottle a month

Best for: people who want to start low and titrate, or who are consolidating a longevity stack with one supplier. View Eternal Elixir Ca-AKG 500mg →

4. Double Wood AKG — Cheapest Per Gram, But Not Calcium AKG

Double Wood Supplements sells the cheapest AKG in this comparison and publishes the most detailed lab data of anyone here — and it still only places fourth, for one reason: it is not calcium alpha-ketoglutarate. Double Wood’s product is pure free-acid alpha-ketoglutaric acid, and the brand says so directly, including a note distinguishing it from AAKG. That honesty is to its credit.

It also means this is not the compound the longevity mouse study used.

On price it is untouchable: 180 capsules at $29.95, 1,000 mg per two-capsule serving, 90 servings per bottle — $0.33 per 1,000 mg and a three-month supply.

Its published batch certificate goes further than any other brand here, listing the actual assay result (931.5 mg against a 900–1,250 mg claim), capsule weight, disintegration time, four heavy metals with measured values, and microbial results, all tied to a named lab and lot number.

The trade-off shows up in the reviews, and it is worth reading. Across 37 reviews averaging 4.5 stars, one detailed three-star review describes the free acid as “very acidic” and difficult to tolerate, with the reviewer neutralizing the powder with baking soda water and explicitly wishing for “an affordable Ca-AKG supplement where I didn’t have to do this procedure.” Another notes capsules arriving broken with loose powder in the bottle.

That is exactly the practical difference between the acid and the calcium salt, described by a buyer rather than a marketer. We cover the brand in more depth in our full Double Wood Supplements review.

Key specs: 180 capsules · free-acid AKG · 1,000 mg per 2-capsule serving · 90 servings · $29.95 · free shipping over $30.

Pros:

• By far the cheapest per gram at $0.33 per 1,000 mg
• Best lab documentation in this comparison — real assay numbers, named lab, lot number
• Three-month supply per bottle
• Largest genuine review base here (37 reviews, 4.5 average)

Cons:

• Not calcium alpha-ketoglutarate — a different compound from the one in the longevity research
• Free-acid form draws repeated tolerability complaints in its own reviews
• Reports of broken capsules and loose powder

Best for: buyers who specifically want free-acid AKG, understand the form difference, and are not buying on the strength of the calcium-AKG mouse data.

5. Renue by Science CaAKG — Best Liposomal Delivery Option

Renue by Science takes a different angle: rather than competing on milligrams, it wraps a smaller 300 mg dose of calcium alpha-ketoglutarate in a powdered liposomal delivery system, one capsule per serving, 90 capsules for $48.95. The label breaks the 300 mg down transparently as 60 mg calcium and 240 mg AKG — the clearest mineral disclosure of any product here.

At $1.81 per 1,000 mg it is the most expensive option in this comparison, and that premium buys a delivery-system claim rather than more compound. Liposomal encapsulation is a reasonable approach in principle, but we have not seen head-to-head human absorption data comparing liposomal Ca-AKG against a standard capsule, so treat the absorption advantage as a hypothesis you are paying for, not an established fact.

Renue is third-party tested and holds a 4.2-star average across 11 reviews. We looked at the brand’s broader range in our Renue by Science NMN review.

Key specs: 90 capsules · 300 mg Ca-AKG per capsule (60 mg calcium, 240 mg AKG) · liposomal · 1 capsule per serving · 90 servings · $48.95.

Pros:

• Clearest mineral breakdown on any label in this group
• Single-capsule serving with a 90-day supply at the label dose
• Third-party tested, vegan, established longevity-focused brand

Cons:

• Most expensive per gram at $1.81 per 1,000 mg
• 300 mg per serving is well below the doses used in the research
• The liposomal absorption advantage is not supported by published head-to-head human data

Best for: buyers already committed to liposomal formats who want a low daily dose in one capsule.

Frequently Asked Questions

What is Ca AKG used for?

Ca-AKG is used as a healthy-aging and cellular-metabolism supplement. Alpha-ketoglutarate is a central intermediate in the Krebs cycle, the pathway cells use to generate energy, and its levels decline with age. The interest in supplementing it comes from rodent research in which calcium AKG extended lifespan in female mice and reduced frailty measures in both sexes.

In humans, it is taken as a general metabolic and healthy-aging support ingredient rather than for any established outcome.

How much does Ca-AKG cost per month in the US?

At a 1,000 mg daily serving, monthly cost ranges from about $10 to $50 depending on the product. Double Wood’s free-acid AKG works out near $10 a month, Toniiq’s Ca-AKG around $12.50, ProHealth exactly $25.25 for a 30-serving bottle, and Eternal Elixir’s Ca-AKG about $49.99 since a 1,000 mg daily serving uses two of its 500 mg capsules.

Renue by Science is priced per 300 mg capsule, so matching a 1,000 mg daily dose there is the most expensive route of all.

How many milligrams of Ca-AKG per day do the studies use?

Most US products are labeled at 1,000 mg per day, but that figure comes from market convention rather than a human dose-finding trial. The foundational lifespan work was done in mice, fed the compound in their diet, and mouse dietary doses do not convert directly into a human milligram figure. There is no established human dose, which is one reason a product that lets you titrate in 500 mg steps is useful.

Is Ca-AKG or NMN the better first purchase?

They target different biology, so it depends on what you are after. NMN is a NAD+ precursor with a growing body of human trial data behind it; Ca-AKG is a Krebs-cycle metabolite whose longevity evidence is mostly preclinical. If you want the option with more human data, most buyers start with NMN.

If you already run a NAD+ precursor and want to add a mechanistically different lever, Ca-AKG is a reasonable second purchase.

Does Ca-AKG need to be liposomal?

There is no published head-to-head human absorption study showing liposomal Ca-AKG outperforms a standard capsule. Liposomal delivery is a plausible approach and Renue by Science’s product is a legitimate version of it, but you are paying a significant premium per gram for a mechanism that has not been demonstrated for this specific compound. A standard Ca-AKG capsule is the better-evidenced default.

Where can I buy Ca-AKG in the US?

All five products here ship domestically. Toniiq, ProHealth, Double Wood and Renue by Science sell direct and through retailers including Amazon, iHerb, Vitacost and Walmart. Eternal Elixir sells direct only, ships in 24 hours, and offers free shipping over $100.

Buying direct from a brand generally means fresher stock and clearer batch traceability than a third-party marketplace listing.

Is the 8-year biological age reduction claim real?

It comes from a real, published paper, but the framing matters. The 2021 Aging study reported that association from a retrospective analysis of customer DNA methylation samples, with authors affiliated to both the supplement manufacturer and the testing company, and no placebo control group. DNA methylation clocks estimate biological age; they do not measure lifespan or disease outcomes.

Treat it as a preliminary signal worth following, not a demonstrated result.

Can you take Ca-AKG with a calcium supplement?

You can, but count the total. A 1,000 mg Ca-AKG serving contributes roughly 200 mg of calcium, about 15% of the daily value. Stack that with a calcium tablet and a fortified multivitamin and the combined intake climbs quickly.

If you already supplement calcium deliberately, factor the Ca-AKG contribution into your total and speak with a qualified healthcare professional about what is appropriate for you.

The Verdict: Which Ca-AKG Supplement Should You Buy?

There is no single best Ca-AKG supplement here. There are three good answers, and the right one depends on what you are optimizing for.

If you want the best value on the studied compound: Toniiq Calcium AKG 1500. At $0.42 per 1,000 mg with 99%+ stated purity and a published certificate of analysis, nothing else in this comparison matches it — and that includes our own product.

If you want the clearest label: ProHealth Calcium AKG Longevity. It declares the calcium fraction openly and gives you a clean 30-day supply at the standard serving.

If you want dose control or you are consolidating a stack: Eternal Elixir Ca-AKG 500mg. It costs more per gram and we have said so plainly, but it is the only single-capsule 500 mg serving here, gives 60 servings per bottle, and sits alongside the rest of a longevity range that ships in 24 hours domestically.

If price is the only criterion and you understand the form difference: Double Wood AKG at $0.33 per 1,000 mg, with the caveat that free-acid AKG is not the compound in the longevity research and draws tolerability complaints.

If you are committed to liposomal formats: Renue by Science CaAKG, accepting the highest per-gram cost in the group for a delivery claim that has not been tested head-to-head in humans.

Whichever you choose, buy on the Supplement Facts panel rather than the front label, and hold the category’s claims to the evidence that actually exists — one strong mouse study with a calcium confound the authors themselves flagged, and no completed randomized human longevity trial.