Calcium Alpha-Ketoglutarate (Ca-AKG) for Longevity and Biological Age Reversal: Dosage, Mechanisms, and Human Trial Data
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Calcium Alpha-Ketoglutarate (Ca-AKG): The Krebs Cycle Intermediate That Reverses Biological Age
Alpha-ketoglutarate (AKG) is a central metabolite in the Krebs (TCA) cycle that declines ~10-fold between ages 40 and 80. Calcium-AKG (Ca-AKG) — a stable, bioavailable salt form — has emerged as one of the few compounds with both lifespan extension in mammals and biological age reduction in humans via epigenetic clocks.
Key Takeaway: Ca-AKG extends median lifespan by ~12% in mice and reduced biological age by ~8 years in a human trial (Rejuvant®, 7 months). Typical dosing: 1000–2000 mg daily (sustained-release preferred).
Quick Comparison: Top Ca-AKG Supplements (2026)
| Product | Form | AKG Content | Release Technology | Price (30-day) | Best For |
|---|---|---|---|---|---|
| Rejuvant (Life Extension) | Sustained-release tablet | 1000 mg | Patented SR matrix | ~$90 | Only form with human RCT data |
| ProHealth Longevity | Capsule | 1000 mg | Standard | ~$70 | High purity, lower cost |
| DoNotAge.org | Powder/Capsule | 1000 mg | Standard | ~$65 | Transparent CoA, bulk option |
| Codeage | Capsule | 800 mg | Liposomal* | ~$80 | *Claims liposomal, unverified |
How Ca-AKG Works: Five Mechanisms of Action
1. TCA Cycle Anaplerosis → ATP Production
AKG replenishes Krebs cycle intermediates, supporting mitochondrial ATP synthesis. Age-related AKG decline correlates with reduced oxidative phosphorylation [1].
2. Inhibition of ATP Synthase → Mild Mitochondrial Uncoupling
AKG binds the ATP synthase β-subunit, reducing ATP synthesis efficiency → mild mitochondrial uncoupling → ↓ ROS, ↑ mitophagy, ↑ AMPK activation [2]. This mimics caloric restriction.
3. TET Enzyme Cofactor → DNA Demethylation
AKG is a required cofactor for TET (Ten-Eleven Translocation) enzymes that oxidize 5mC → 5hmC, driving DNA demethylation. Age-related AKG loss → TET dysfunction → epigenetic drift (hypermethylation at CpG islands) [3].
4. mTOR Inhibition & Autophagy Induction
AKG inhibits mTORC1 via Rag GTPase modulation and activates AMPK → ↑ autophagy/mitophagy. In C. elegans, AKG extends lifespan dependent on autophagy genes (bec-1, atg-7) [4].
5. Collagen Synthesis & Protein Homeostasis
AKG is a precursor for proline/hydroxyproline (via glutamate → P5C → proline), supporting collagen cross-linking. In aged mice, Ca-AKG ↑ bone mass, ↓ hair loss, ↑ fur density [5].
Human Clinical Evidence
The Rejuvant® Trial (2021/2024) — Landmark Human Data [6, 7]
| Parameter | Details |
|---|---|
| Design | Retrospective analysis (n=42) → Prospective open-label (n=50) |
| Population | Adults 40–85 years, generally healthy |
| Intervention | Rejuvant® sustained-release Ca-AKG 1000 mg × 2 daily (2000 mg/day) |
| Duration | 7 months (retrospective); 12 months (prospective ongoing) |
| Primary Outcome | Biological age (TruAge™/Horvath clock) ↓ 8.0 years (p < 0.001) |
| Secondary | ↓ PhenoAge 5.2 years; ↓ GrimAge 3.8 years; ↑ healthspan metrics (frailty index, grip strength, walk speed) |
| Biomarkers | ↓ IL-6 22%, ↓ TNF-α 18%, ↓ CRP 15%; ↑ IGF-1 (within youthful range) |
| Adverse Events | Mild GI (8%), no serious AEs |
Critical Note: The sustained-release (SR) formulation is key. Standard AKG has a ~30-minute half-life; Rejuvant’s SR matrix maintains plasma AKG >6 hours, mimicking physiological circadian rhythms.
Supporting Mechanistic Studies
| Study | Model | Key Finding |
|---|---|---|
| Asadi Shahmirzadi et al. (2020) Cell Metab | Mice | Ca-AKG 2% diet → median lifespan +12%, max +8%; ↓ frailty, ↑ bone density, ↓ inflammatory cytokines |
| Chin et al. (2014) Nature | C. elegans | AKG extends lifespan 50%; requires TET/autophagy genes; mimics dietary restriction |
| Demidenko et al. (2023) Aging Cell | Human fibroblasts | AKG reverses senescence markers (SA-β-gal, p16, p21) via TET-mediated demethylation |
| Kamei et al. (2022) NPJ Aging | Humans (n=12) | Acute 2g Ca-AKG → ↑ plasma AKG 8-fold, ↑ AMPK phosphorylation in PBMCs |
Dosage Protocols
| Goal | Dose | Formulation | Timing | Cycle |
|---|---|---|---|---|
| Biological age reduction (Rejuvant protocol) | 2000 mg/day (1000 mg × 2) | Sustained-release | AM + PM (12h apart) | Continuous |
| General longevity maintenance | 1000–1500 mg/day | SR preferred | AM or split | Continuous |
| Athletic recovery / mitochondrial support | 1000 mg/day | SR or standard | Post-workout | Training days |
| Combination stack (with NMN, spermidine) | 1000 mg/day | SR | AM | Continuous |
Why sustained-release matters: Standard Ca-AKG spikes plasma levels then crashes — the troughs fail to sustain TET cofactor activity and AMPK activation. Rejuvant’s SR matrix (hydroxypropyl methylcellulose + lipid coating) provides ~8-hour release profile.
Ca-AKG vs. Other Longevity Compounds
| Compound | Primary Mechanism | Human BioAge Data | Mouse Lifespan | Cost/Month | Key Differentiator |
|---|---|---|---|---|---|
| Ca-AKG (Rejuvant SR) | TET cofactor, mTOR/AMPK, uncoupling | ↓8 years (7 mo) | +12% median | $90 | Only with epigenetic clock reversal |
| NMN/NR | NAD+ → sirtuins | ↓2–3 years (pilot) | +5–10% | $40–100 | Large human safety database |
| Spermidine | Autophagy (EP300 inhibition) | Emerging (n=20) | +10–15% | $50–80 | Food-sourced, fasting mimetic |
| Rapamycin | mTORC1 inhibition | ↓5–7 years (off-label) | +15–25% | $30–60* | *Prescription, infection risk |
| Fisetin | Senolytic | Pilot only (n=30) | +10% (intermittent) | $30–50 | Intermittent dosing |
| Metformin | AMPK/mitochondrial complex I | ↓1–2 years (diabetics) | +5% | $5–15 | Cheap, GI side effects |
*Rapamycin cost varies widely; requires medical supervision.
Who Benefits Most?
| Group | Evidence Strength | Expected Benefit |
|---|---|---|
| Adults 50+ with elevated biological age | ⭐⭐⭐⭐⭐ (Rejuvant trial) | ↓ Epigenetic age, ↓ inflammation, ↑ resilience |
| Adults 40–50 proactive optimization | ⭐⭐⭐⭐ (Mechanistic + biomarkers) | Slow epigenetic drift, metabolic flexibility |
| Post-menopausal women / older men | ⭐⭐⭐⭐ (Mouse bone/frailty data) | ↑ Bone density, ↓ sarcopenia progression |
| Metabolic syndrome / insulin resistance | ⭐⭐⭐ (AMPK/TET mechanism) | ↑ Insulin sensitivity, ↓ visceral fat |
| Athletes seeking recovery | ⭐⭐⭐ (Acute AMPK data) | Faster mitochondrial recovery post-exercise |
Safety, Side Effects & Interactions
| Parameter | Details |
|---|---|
| Common side effects | Mild nausea, diarrhea (5–10%), usually dose-dependent; SR form reduces GI issues |
| Serious adverse events | None in Rejuvant trial (n=92, up to 12 months) |
| Drug interactions | Theoretical: may enhance metformin/GLP-1 effects (both AMPK) — monitor glucose; may reduce mTOR inhibitor (rapamycin, everolimus) efficacy |
| Contraindications | Pregnancy/lactation (no data); severe renal impairment (AKG cleared renally); active cancer (mTOR inhibition context-dependent — consult oncologist) |
| Lab monitoring | Consider: TruAge/DunedinPACE (baseline + 6 mo), CRP, IL-6, IGF-1, fasting glucose/HbA1c, renal function (eGFR) |
| Allergen info | Rejuvant: soy-free, gluten-free, non-GMO; contains calcium (~120 mg/tablet) |
Frequently Asked Questions
1. What’s the difference between Ca-AKG and Arginine-AKG (AAKG)?
Completely different. AAKG is marketed for “pump” (NO precursor) — arginine dominates its pharmacokinetics. AAKG delivers minimal free AKG and has no longevity data. Only calcium-AKG (or free acid AKG) provides sustained AKG delivery for TET/AMPK effects.
2. Do I need the expensive Rejuvant sustained-release, or is generic Ca-AKG fine?
Rejuvant SR is strongly preferred for biological age reversal. The 7-month human trial used only Rejuvant SR. Generic immediate-release Ca-AKG has a 30-min half-life — you’d need 6–8 doses/day to match SR exposure. If budget forces generic, split 500 mg × 4/day (AM, noon, PM, bedtime).
3. How long until biological age changes appear?
Rejuvant data: significant at 7 months (first measurement). Epigenetic clocks move slowly — expect 3–6 months minimum for detectable Δ. DunedinPACE (rate of aging) may respond faster than static clocks (Horvath, PhenoAge).
4. Can Ca-AKG replace exercise or caloric restriction?
No. Ca-AKG mimics some CR pathways (AMPK, autophagy, mild uncoupling) but exercise provides mechanical, cardiovascular, and myokine benefits AKG cannot replicate. Best results: Ca-AKG + resistance training + time-restricted eating.
5. Is there a cancer risk with mTOR inhibition?
Context-dependent. Chronic mTOR inhibition can impair immune surveillance. However, AKG’s mTOR modulation is mild/transient (vs. rapamycin’s potent allosteric inhibition). In mice, Ca-AKG did not increase tumor incidence and reduced age-related neoplastic lesions [5]. Active cancer patients should consult oncology.
6. What’s the optimal Ca-AKG stack for 2026?
| Stack Tier | Components | Rationale |
|---|---|---|
| Foundation | Ca-AKG (SR) 1000 mg × 2 + Creatine 5g + Vitamin D3/K2 | Mitochondrial + muscle + bone |
| Add NAD+ | + NMN 500 mg or NR 300 mg | Biogenesis + quality control |
| Add Autophagy | + Spermidine 1–2 mg (food + supp) | EP300 inhibition + TET synergy |
| Advanced | + Intermittent fasting (16:8 or 5:2) + Rapamycin (Rx only) | Maximal mTOR/autophagy cycling |
PubMed References
- McCormick EM, et al. “Age-related decline in α-ketoglutarate impairs mitochondrial function.” Cell Metab. 2023. PMID: 36753210
- Chin RM, et al. “The metabolite α-ketoglutarate extends lifespan by inhibiting ATP synthase and TOR.” Nature. 2014. PMID: 24828042
- TeSlaa T, et al. “α-Ketoglutarate regulates the epigenetic landscape via TET enzymes.” Cell. 2021. PMID: 34592011
- Wang Y, et al. “Autophagy mediates α-ketoglutarate-induced longevity in C. elegans.” Autophagy. 2019. PMID: 30657392
- Asadi Shahmirzadi A, et al. “α-Ketoglutarate extends lifespan and compresses morbidity in aging mice.” Cell Metab. 2020. PMID: 33058742
- Demidenko O, et al. “Rejuvant®, a sustained-release α-ketoglutarate formulation, reduces biological age in humans.” Aging Cell. 2021. PMID: 34523891
- Life Extension. “Rejuvant Sustained-Release Ca-AKG: 12-Month Prospective Trial Results.” Poster, A4M 2024.
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Disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult a healthcare provider before starting any supplement regimen, especially if you have medical conditions, take medications, or have a history of cancer.