on September 27, 2026
Quick answer: Calcium alpha-ketoglutarate, or Ca-AKG, is a calcium salt of alpha-ketoglutarate. It combines alpha-ketoglutarate with calcium in one ingredient form. Product labels should be checked for the declared serving amount, the amount of elemental calcium, and the exact AKG form used.
The ingredient form matters because scientific findings remain connected to the compound, formulation, population and dose studied. Research involving Ca-AKG provides information about that calcium salt. A label listing another AKG form requires its own interpretation.
Key Takeaways
- Ca-AKG is a calcium salt of alpha-ketoglutarate.
- AKG, alpha-ketoglutaric acid and 2-oxoglutaric acid belong to the same biochemical naming family, while Ca-AKG identifies a specific calcium salt.
- Ca-AKG may contribute elemental calcium, so the Supplement Facts panel deserves separate review.
- Human Ca-AKG research currently includes one small randomized study, one retrospective multi-ingredient analysis and a registered randomized trial with results pending.
- NyxSeren Luna lists AKG (2-Oxoglutaric Acid), 200 mg per two-capsule serving. Ca-AKG remains a separate ingredient form.
What Is a Ca-AKG Supplement?
AKG is short for alpha-ketoglutarate, an endogenous metabolite involved in the tricarboxylic acid cycle, also called the TCA or citric acid cycle. This cycle helps cells process nutrients and connect carbohydrate, fat and amino-acid metabolism.
Scientific sources may use several closely related names:
- Alpha-ketoglutaric acid describes the acid form.
- 2-oxoglutaric acid is another established name for the same parent acid.
- Alpha-ketoglutarate describes the corresponding ion and is commonly shortened to AKG.
- Calcium alpha-ketoglutarate describes a calcium salt and is commonly shortened to Ca-AKG.
Supplement marketing often places these terms under the broad AKG category. Precise evaluation starts with the full ingredient name on the label.
| Label Term | What It Identifies | What to Check |
|---|---|---|
| Alpha-ketoglutaric acid | The parent acid form | Declared amount, serving size and formulation |
| 2-oxoglutaric acid | An established alternative name for alpha-ketoglutaric acid | Whether the product uses the acid or a mineral salt |
| Alpha-ketoglutarate or AKG | A broad term frequently used for the metabolite and supplement category | The complete chemical form listed elsewhere on the label |
| Calcium alpha-ketoglutarate or Ca-AKG | A calcium salt of alpha-ketoglutarate | Full compound amount and declared elemental calcium |
| Sustained-release Ca-AKG | Ca-AKG combined with a controlled-release delivery design | Release technology, serving instructions and supporting evidence |
Why Do Supplement Manufacturers Use Ca-AKG?
Mineral salts are commonly used to create stable ingredient forms and defined manufacturing specifications. In Ca-AKG, calcium serves as the mineral component of the salt.
The calcium component creates an additional label question: how much elemental calcium does one serving provide? The weight of a calcium-containing compound and the amount of elemental calcium describe different measurements.
When calcium is declared as a dietary mineral, the Supplement Facts panel reports the amount of elemental calcium. The source may be identified in parentheses, such as “Calcium (as calcium carbonate).” Consumers can therefore review the calcium amount directly instead of estimating it from the total weight of a mineral salt.
The label should also make clear whether the stated milligrams describe the full Ca-AKG ingredient, an AKG equivalent or another defined specification. Contacting the manufacturer is appropriate when the panel leaves that distinction unclear.
What Does Human Research Say About Ca-AKG?
The human evidence base remains limited and study-specific. Existing research covers different populations, formulations and outcomes, so each finding requires its original context.
A 2007 Randomized Study in Postmenopausal Women
A six-month randomized, double-blind study included 76 postmenopausal women with osteopenia. One group received the calcium salt of alpha-ketoglutaric acid, supplying 6 g of AKG and 1.68 g of calcium per day. The comparison group received the same daily amount of calcium without AKG.
The Ca-AKG group showed a greater decrease in serum CTX, a marker related to bone resorption. Lumbar spine bone mineral density increased from baseline in the Ca-AKG group, while the between-group BMD difference remained statistically nonsignificant.
This study addresses a specific population, a high research dose and bone-related outcomes. Its results provide evidence for that protocol and population.
A 2021 Retrospective DNA Methylation Analysis
A retrospective analysis followed 42 individuals who used a commercial sustained-release Ca-AKG formulation for an average of approximately seven months. The formulation also included vitamin A for men or vitamin D for women.
The investigators reported an average reduction of approximately eight years in DNA methylation age as measured by the proprietary TruAge test. The analysis used a multi-ingredient commercial formula, included a small self-selected group and had no randomized placebo control.
The result is hypothesis-generating. Randomized trials, independent replication and multiple validated aging measures are needed before drawing broader conclusions about biological aging.
The ABLE Randomized Trial
The ABLE study is a randomized, placebo-controlled trial investigating Ca-AKG in middle-aged adults. Its protocol evaluates DNA methylation age alongside physical, metabolic, cardiovascular, sleep and quality-of-life measurements.
As of September 2026, ClinicalTrials.gov lists the trial as active and closed to recruitment. The record reports an actual primary completion date of August 15, 2025, an estimated overall completion date of January 15, 2027 and zero posted study results.
The ABLE trial may provide stronger human evidence because of its randomized, blinded and placebo-controlled design. Conclusions should follow the published results when they become available.
| Evidence Source | Design | What Was Studied | Interpretation Boundary |
|---|---|---|---|
| Filip et al., 2007 | Six-month randomized, double-blind human trial | 76 postmenopausal women with osteopenia; Ca-AKG versus calcium | Specific population, high research dose and bone-related endpoints |
| Demidenko et al., 2021 | Retrospective human analysis | 42 users of sustained-release Ca-AKG plus sex-specific vitamins | Small self-selected cohort, multi-ingredient formula and proprietary methylation test |
| Shahmirzadi et al., 2020 | Preclinical mouse study | Ca-AKG, frailty, healthspan and lifespan in aging mice | Animal findings support human research questions and require human confirmation |
| ABLE trial, NCT05706389 | Randomized, blinded, placebo-controlled human trial | Estimated 120 middle-aged adults; Ca-AKG and multiple aging-related measures | Recruitment closed; results remain pending |
What Do Animal Studies Add?
A 2020 study supplied Ca-AKG to aging mice and reported reductions in frailty together with changes in lifespan and inflammatory signaling. This study helped increase scientific interest in Ca-AKG as a geroscience research compound.
Animal studies can reveal mechanisms and support the design of human trials. Human outcomes depend on human studies using defined formulations, clinically relevant measures and appropriate comparison groups.
A 2022 review of AKG supplementation reached a similarly cautious conclusion: AKG participates in important metabolic and cellular pathways, while recent human evidence for aging-related outcomes remains limited.
How to Read a Ca-AKG Supplement Label
A useful label review separates ingredient identity, serving amount, calcium contribution and delivery design.
| Label Check | Question to Ask | Why It Matters |
|---|---|---|
| Exact form | Does the label say Ca-AKG, alpha-ketoglutaric acid, 2-oxoglutaric acid or another form? | Research remains connected to the form studied. |
| Amount definition | Do the milligrams describe the full compound or a standardized AKG equivalent? | Different declarations can produce misleading dose comparisons. |
| Elemental calcium | How much calcium does one serving contribute? | Total calcium intake may include food and other supplements. |
| Serving size | How many capsules provide the declared amount? | Front-label numbers can represent more than one capsule. |
| Delivery design | Is the product immediate-release or sustained-release? | Release format is a separate formulation feature. |
| Companion ingredients | Does the formula include vitamins, minerals or other active ingredients? | Multi-ingredient results cannot isolate the contribution of Ca-AKG. |
Is There an Established Ca-AKG Dosage?
Ca-AKG has no established U.S. Daily Value or universal evidence-based intake for healthy aging. Published protocols also vary substantially.
The 2007 bone study supplied 6 g of AKG per day as a calcium salt. The retrospective commercial-formula analysis used its own sustained-release product protocol. The ABLE trial protocol describes 1 g of Ca-AKG per day.
These quantities belong to separate studies with different populations, formulations and outcomes. Product directions and qualified professional guidance provide the practical basis for individual use.
Where NyxSeren Luna Fits
NyxSeren Luna Nightly Repair & Renewal lists AKG (2-Oxoglutaric Acid): 200 mg per two-capsule serving.
Luna’s declared ingredient is the acid form. Ca-AKG is a separate calcium salt. Research performed with Ca-AKG should therefore remain attached to Ca-AKG when evaluating study results.
Luna places AKG within a multi-ingredient nighttime renewal routine that also includes ergothioneine, spermidine, theanine, GABA, tryptophan, 5-HTP, vitamin B6 and other ingredients. Product-level outcomes require evidence on the complete formula.
For a wider review of AKG pathways and current evidence, read the guide to alpha-ketoglutarate supplements and nighttime renewal support.
Readers building a broader routine can also explore the guides to cellular health supplements and day-and-night supplement timing.
Safety and Medication Considerations
Ca-AKG contributes calcium as part of its salt form, so total calcium intake deserves review alongside food, multivitamins and other mineral supplements.
Calcium-containing supplements can affect the use or absorption of certain medicines. NIH Office of Dietary Supplements identifies interactions involving calcium supplements or specific calcium salts with medicines including dolutegravir, levothyroxine, lithium and quinolone antibiotics.
Product-specific spacing instructions and qualified professional guidance are appropriate for people using prescription medication. The same guidance applies to pregnancy, breastfeeding, kidney conditions, calcium-balance disorders, planned medical procedures and routines containing several overlapping supplements.
The Bottom Line
Ca-AKG is a specific calcium salt within the wider AKG category. Its calcium component, serving definition and delivery design all affect how a supplement label should be interpreted.
Current research provides plausible biological rationale, encouraging preclinical findings and early human signals. Human evidence remains preliminary, and the most informative randomized aging study has yet to publish results.
A disciplined evaluation starts with four questions: What exact AKG form is listed? What amount does one serving provide? How much elemental calcium is declared? Does the evidence match the ingredient and formulation being considered?
Sources
- PubChem: 2-Oxoglutaric Acid
- Randomized study of AKG calcium salt in postmenopausal women
- Ca-AKG, lifespan and morbidity in aging mice
- Retrospective analysis of a sustained-release Ca-AKG formulation
- Review of alpha-ketoglutarate supplementation in humans
- ABLE randomized trial protocol
- ClinicalTrials.gov: ABLE trial NCT05706389
- NIH Office of Dietary Supplements: Calcium
- FDA dietary supplement ingredient-labeling guidance
Frequently Asked Questions
What is a Ca-AKG supplement?
A Ca-AKG supplement provides calcium alpha-ketoglutarate, a calcium salt of alpha-ketoglutarate. The label should identify the serving amount, exact ingredient form and elemental calcium contribution.
How does Ca-AKG relate to AKG?
AKG is a broad term for alpha-ketoglutarate. Ca-AKG identifies a specific calcium salt within that category. Research findings should remain connected to the exact form and formulation studied.
Does Ca-AKG provide calcium?
Ca-AKG contains calcium as part of its salt form. The Supplement Facts panel should state the amount of elemental calcium when calcium is declared as a dietary mineral.
What human research has evaluated Ca-AKG?
Human research includes a six-month randomized study in 76 postmenopausal women, a 42-person retrospective multi-ingredient analysis and the registered randomized ABLE trial with results pending. The studies vary in population, formulation and outcome.
Which AKG form is listed in NyxSeren Luna?
NyxSeren Luna lists AKG (2-Oxoglutaric Acid), 200 mg per two-capsule serving. Ca-AKG is a separate calcium salt and should be evaluated as a different ingredient form.