Acid vs salt
Alpha-ketoglutaric acid on its own is acidic. Binding it to calcium forms a salt that is less acidic and easier to press into a stable tablet. "Monohydrate" means each unit of the salt carries one water molecule in its crystal structure, which is how the ingredient is weighed and listed.
How much calcium that adds
The salt contributes calcium as well as AKG. The label lists 190 mg of calcium per serving from the Ca-AKG, which is 15% of the Daily Value. Anyone tracking total calcium from food and other supplements can add this figure.
Ca-AKG vs other AKG forms
| Form | What it is | In SDAI AKG? |
|---|---|---|
| Calcium alpha-ketoglutarate (Ca-AKG) | Calcium salt of AKG | Yes |
| Alpha-ketoglutaric acid | The free acid | No |
| AAKG (arginine alpha-ketoglutarate) | AKG bound to the amino acid arginine, common in sports products | No |
Because AAKG and Ca-AKG share the letters "AKG", articles about one are sometimes read as being about the other. They are different ingredients.
Where the research stands
Researchers at the National University of Singapore published a 2022 review of AKG supplementation in humans in Trends in Endocrinology & Metabolism (Gyanwali et al., 2022). It describes the human evidence base as still developing. More sources are on the research page.