What the evidence says. Graded preliminary: the striking '8-year younger' claim comes from an uncontrolled, company-linked retrospective analysis of 42 customers, and the first proper placebo-controlled trial (ABLE, n=120) has not yet reported; the strongest data remain mouse studies. (Preliminary evidence: Early or small human trials; promising but not yet conclusive.)
What is Calcium Alpha-Ketoglutarate (Ca-AKG)?
Calcium Alpha-Ketoglutarate (Ca-AKG) (Calcium 2-oxoglutarate) is a longevity supplement used for lifespan and frailty benefits in mice (not yet shown in people). NutriDex grades the human evidence as Preliminary. Alpha-ketoglutarate (AKG) is a natural intermediate of the Krebs cycle, the chemistry cells use to make energy; blood levels fall with age. Interest exploded after a 2020 Buck Institute study in which calcium AKG given to middle-aged mice reduced frailty and modestly extended lifespan, especially in females. In humans, the headline claim — an average 8-year drop in DNA-methylation 'biological age' — comes from a 2021 retrospective analysis of 42 people taking the product Rejuvant for about 7 months, with no placebo group and authors linked to the manufacturer and test provider. A 2026 cross-sectional study of 4,260 epigenetic-test buyers found Rejuvant users had about 1.8 years lower age residuals, but plain AKG users showed no significant benefit, and healthy-user bias is likely. Older small RCTs showed 6 g/day AKG-calcium cut a bone-breakdown marker by 37% in osteopenic women without a significant bone-density difference. The 120-person placebo-controlled ABLE trial in Singapore will be the first real test.
Purported Benefits
✓Lifespan and frailty benefits in mice (not yet shown in people)
✓Possible slowing of bone turnover in postmenopausal women
✓Phosphate binder in dialysis (older medical use)
✓Claimed epigenetic-age reduction (uncontrolled data only)
Dosing & Compounds
Typical Dose
Longevity products typically supply 1 g/day of (often sustained-release) Ca-AKG, the dose now being tested in the placebo-controlled ABLE trial; no dose is proven to slow human ageing.
Active Compounds
Alpha-ketoglutarate (2-oxoglutarate)Calcium (~20% by weight)
Safety & Cautions
⚠
At 1 g/day Ca-AKG is generally well tolerated in short studies, but gastrointestinal upset (nausea, loss of appetite, diarrhoea) is the main side effect and led 29% of dialysis patients to stop higher-dose calcium ketoglutarate in one trial. Each gram supplies roughly 200 mg of calcium, which counts toward total intake for people with kidney disease, kidney stones or high blood calcium, and calcium can reduce absorption of thyroid hormone, tetracycline/quinolone antibiotics and bisphosphonates if taken together. Long-term safety for 'anti-ageing' use in healthy people has not been studied, and branded formulas often add vitamins A or D. Educational only — always check with your doctor or pharmacist before combining Calcium Alpha-Ketoglutarate (Ca-AKG) with any medicine.
Common questions about Calcium Alpha-Ketoglutarate (Ca-AKG)
What is Calcium Alpha-Ketoglutarate (Ca-AKG) used for?
Calcium Alpha-Ketoglutarate (Ca-AKG) is most often taken for Lifespan and frailty benefits in mice (not yet shown in people), Possible slowing of bone turnover in postmenopausal women, Phosphate binder in dialysis (older medical use), Claimed epigenetic-age reduction (uncontrolled data only). A Krebs-cycle metabolite sold to cut 'biological age' — unproven.
Does Calcium Alpha-Ketoglutarate (Ca-AKG) work — what does the evidence say?
Preliminary evidence. Early or small human trials; promising but not yet conclusive. Alpha-ketoglutarate (AKG) is a natural intermediate of the Krebs cycle, the chemistry cells use to make energy; blood levels fall with age. Interest exploded after a 2020 Buck Institute study in which calcium AKG given to middle-aged mice reduced frailty and modestly extended lifespan, especially in females. In humans, the headline claim — an average 8-year drop in DNA-methylation 'biological age' — comes from a 2021 retrospective analysis of 42 people taking the product Rejuvant for about 7 months, with no placebo group and authors linked to the manufacturer and test provider. A 2026 cross-sectional study of 4,260 epigenetic-test buyers found Rejuvant users had about 1.8 years lower age residuals, but plain AKG users showed no significant benefit, and healthy-user bias is likely. Older small RCTs showed 6 g/day AKG-calcium cut a bone-breakdown marker by 37% in osteopenic women without a significant bone-density difference. The 120-person placebo-controlled ABLE trial in Singapore will be the first real test.
What is the typical dose of Calcium Alpha-Ketoglutarate (Ca-AKG)?
Longevity products typically supply 1 g/day of (often sustained-release) Ca-AKG, the dose now being tested in the placebo-controlled ABLE trial; no dose is proven to slow human ageing.
Is Calcium Alpha-Ketoglutarate (Ca-AKG) safe? Any cautions or side effects?
At 1 g/day Ca-AKG is generally well tolerated in short studies, but gastrointestinal upset (nausea, loss of appetite, diarrhoea) is the main side effect and led 29% of dialysis patients to stop higher-dose calcium ketoglutarate in one trial. Each gram supplies roughly 200 mg of calcium, which counts toward total intake for people with kidney disease, kidney stones or high blood calcium, and calcium can reduce absorption of thyroid hormone, tetracycline/quinolone antibiotics and bisphosphonates if taken together. Long-term safety for 'anti-ageing' use in healthy people has not been studied, and branded formulas often add vitamins A or D.
How many studies support Calcium Alpha-Ketoglutarate (Ca-AKG)?
NutriDex cites 10 sources for Calcium Alpha-Ketoglutarate (Ca-AKG), graded "Preliminary".
Cite this page
APA
Peh, D. (2026). Calcium Alpha-Ketoglutarate (Ca-AKG) (Calcium 2-oxoglutarate): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 18 Oct 2026, from https://nutridex.info/s/ca-akg
BibTeX
@misc{nutridex_ca_akg,
author = {Peh, Daryl},
title = {Calcium Alpha-Ketoglutarate (Ca-AKG) (Calcium 2-oxoglutarate): Benefits, Dosage, Side Effects \& Evidence},
year = {2026},
howpublished = {NutriDex --- The Supplement Research Compendium},
url = {https://nutridex.info/s/ca-akg},
note = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-10-18}
}
For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.