Alpha-Ketoglutarate (AKG, α-KG)

What is alpha-ketoglutarate?

Alpha-ketoglutarate is a Krebs cycle intermediate that has emerged as a longevity compound through a convergence of mechanisms: it’s a required co-factor for TET enzymes, which demethylate DNA and regulate epigenetic aging; it modulates mTOR activity through a metabolic route; it supports collagen synthesis as a co-factor for prolyl hydroxylases; and its levels decline significantly with age. The Rejuvant trial — a small but landmark human study — showed that calcium AKG supplementation reduced biological age as measured by epigenetic clocks by an average of 8 years over roughly 7 months in middle-aged adults.

The epigenetic angle is what distinguishes AKG from other metabolic longevity compounds. TET enzymes are the primary DNA demethylases — they reverse aberrant DNA methylation that accumulates with aging and drives gene expression changes associated with the aging phenotype. AKG is required as a co-factor for TET enzyme activity. When AKG levels decline with age, TET enzyme activity is reduced, DNA methylation patterns become dysregulated, and the epigenetic aging clock advances faster. Supplemental AKG may help maintain TET enzyme activity and slow this epigenetic drift.

AKG also modulates mTOR through a distinct mechanism from rapamycin: it inhibits ATP synthase, raising the AMP:ATP ratio, which activates AMPK and suppresses mTOR. This creates an mTOR-suppressing effect from a different angle than rapamycin or berberine — potentially additive in a comprehensive longevity stack. Additionally, AKG is the required co-factor for prolyl hydroxylases that modify proline residues during collagen synthesis, making it directly relevant to connective tissue and bone health.

The Rejuvant trial is the primary reason AKG has entered serious longevity conversations: 42 participants aged 42-78 took CaAKG for an average of 7 months, and biological age measured by the Horvath epigenetic clock decreased by a mean of 8 years, with physical health composite scores improving significantly. This is a small, uncontrolled pilot study — not a Phase III RCT — but the epigenetic clock findings are unusually specific and the effect size is large enough to take seriously. AKG often appears alongside NMN and rapamycin in epigenetically-focused longevity stacks.

How it works

TET Enzyme Co-Factor — Epigenetic Regulation

TET (ten-eleven translocation) enzymes catalyze the oxidation of 5-methylcytosine to 5-hydroxymethylcytosine — the first step in DNA demethylation. TET enzymes are 2-oxoglutarate-dependent dioxygenases: they require AKG as an obligate co-factor along with oxygen and Fe²⁺. When AKG is limiting, TET activity is reduced, and aberrant DNA methylation patterns accumulate. Supplemental AKG restores TET co-factor availability, maintaining or improving DNA demethylation activity and potentially slowing epigenetic aging clock progression.

mTOR Suppression via ATP Synthase Inhibition

AKG inhibits mitochondrial ATP synthase — the enzyme that produces ATP from the proton gradient. This inhibition raises the AMP:ATP ratio, activating AMPK, which in turn suppresses mTOR. This is a third distinct mechanism for mTOR suppression alongside rapamycin’s direct mTORC1 inhibition and berberine/metformin’s Complex I → AMPK route. For a comprehensive longevity stack, AKG adds mTOR suppression through a metabolic rather than pharmacological mechanism.

Collagen Synthesis — Prolyl Hydroxylase Co-Factor

Prolyl hydroxylases modify proline residues in procollagen, producing hydroxyproline — essential for collagen’s triple helix structure and stability. These enzymes also require AKG as a co-factor. AKG supplementation supports prolyl hydroxylase activity, theoretically supporting collagen synthesis in bone, cartilage, skin, and connective tissue. This mechanism distinguishes AKG as relevant to structural tissue health beyond epigenetics.

What the research shows

What the community reports

AKG’s community profile is dominated by one study — the Rejuvant trial — and by its place in a small number of high-profile longevity protocols.

Common misconceptions