L-Carnitine
Dosage Protocol
L-Carnitine is an amino acid derivative synthesized from lysine and methionine that serves as the essential transporter of long-chain fatty acids across the inner mitochondrial membrane for beta-oxidation. Injectable L-carnitine achieves significantly higher bioavailability than oral forms and is used clinically for carnitine deficiency, cardiovascular disease, and as a metabolic and recovery agent in research protocols.
What is L-Carnitine?
L-Carnitine (β-hydroxy-γ-trimethylaminobutyric acid) is synthesized endogenously in the liver and kidneys from lysine and methionine, with vitamin C as a cofactor. It is concentrated in tissues with high fatty acid oxidation demands — skeletal muscle, cardiac muscle, and brain. Its primary function is the carnitine palmitoyltransferase (CPT)-mediated transport of long-chain acyl-CoAs across the impermeable inner mitochondrial membrane.
Injectable L-carnitine achieves near-complete bioavailability compared to approximately 10–25% oral absorption. Clinical applications include carnitine deficiency (including dialysis-associated deficiency), cardiovascular disease, male infertility, and metabolic support. Injectable protocols are used in longevity and performance medicine for metabolic optimization, with emerging evidence for insulin sensitization and cognitive support.
Dosing Schedule
Parameters documented in published preclinical and clinical research.
| Phase | Dose | Frequency | Duration | Notes |
|---|---|---|---|---|
| IV protocol | 1000–2000 mg in saline | 2–3× weekly | 8–12 weeks | Note: typically supplied pre-mixed at 200–500 mg/mL — no reconstitution needed. Dilute in 100 mL saline for IV. Infuse over 15–30 min. |
| IM | 500–1000 mg | Daily or every other day | 8–12 weeks | IM. Confirm your product is supplied as ready-to-use liquid before attempting reconstitution. |
| Metabolic | 2000 mg IV | 3× weekly | 12 weeks | Higher dose for insulin sensitization research protocols. |
| Maintenance | 500 mg IM | 2× weekly | Ongoing | Lower-frequency maintenance between intensive cycles. |
Safety & Side Effects
Academic References
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[1]
Rebouche CJ. (2004). Kinetics, pharmacokinetics, and regulation of L-carnitine and acetyl-L-carnitine metabolism. Ann N Y Acad Sci. 1033:30–41. PubMed ↗
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[2]
Longo N, et al. (2006). Disorders of carnitine transport and the carnitine cycle. Am J Med Genet C Semin Med Genet. 142C(2):77–85. PubMed ↗
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[3]
Stephens FB, et al. (2006). Carnitine and skeletal muscle metabolism. J Physiol. 570(Pt 3):525–34. PubMed ↗
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[4]
Ruggenenti P, et al. (2016). Ameliorating hypertension and insulin resistance in subjects at increased cardiovascular risk: effects of acetyl-L-carnitine therapy. Hypertension. 54(3):567–74. PubMed ↗