L-Carnitine

About L-Carnitine (Injectable)

L-Carnitine is a naturally occurring amino acid derivative that transports long-chain fatty acids into the mitochondria, where they are oxidized (“burned”) for energy. Injectable L-carnitine bypasses the poor oral bioavailability of the compound and is researched for fat oxidation, endurance, athletic recovery, increasing intramuscular carnitine stores, and long-term mitochondrial support. Timing of administration is goal-dependent (see below).

Dosing Guide

— Pre-Mixed Injectable Solution (500 mg/mL; 10 units = 50 mg) —

Reconstitute: Not required — L-carnitine is supplied as a pre-mixed injectable solution.
Administration: Subcutaneous injection.
Timing (goal-dependent): For fat oxidation, endurance, or a “lipotropic” protocol — take fasted, 30–60 minutes before cardio. To increase intramuscular carnitine stores, for athletic recovery, or long-term mitochondrial support — take with carbohydrates, a meal, or post-workout nutrition to improve retention and utilization.
Storage: Store per manufacturer instructions; refrigerate after opening and avoid freeze-thaw cycles.

Schedule: Once daily (higher doses may be split into morning and evening).
Cycle Length: 12-week cycle, followed by a 6–12 week washout period.
Goal: Fat oxidation, endurance, recovery, and mitochondrial support.

Standard Protocol

Phase	Dose	Syringe (U-100)
Weeks 1–2	50 mg	10 units (0.10 mL), 1x/day
Weeks 3–8	100 mg	20 units (0.20 mL), 1x/day
Weeks 9–12	150–200 mg	30–40 units (0.30–0.40 mL), once daily or split AM/PM

Note: At the Weeks 9–12 dose, splitting into a morning and evening injection can improve comfort and absorption.

Benefits

• Enhances fat oxidation by shuttling long-chain fatty acids into mitochondria.
• Supports endurance and exercise performance.
• Improves recovery from training; studied for reduced muscle soreness and tissue damage markers.
• Increases intramuscular carnitine stores when paired with carbohydrate intake.
• Supports long-term mitochondrial and metabolic health.
• Commonly used in “lipotropic” fat-loss protocols.

Side Effects

While side effects are not common, you may experience:

• Irritation, redness, or soreness at the injection site
• Nausea or stomach upset
• Fishy body odor at higher doses (a known effect of carnitine metabolism)
• Headaches
• Diarrhea (more common with oral use)

Contraindications

• Do not use when pregnant or nursing.
• Use caution with hypothyroidism — carnitine may interfere with thyroid hormone action.
• Use caution with seizure disorders; carnitine has been associated with increased seizure frequency in susceptible individuals.
• Those with kidney disease should consult a physician — carnitine clearance is renal.
• Elevated TMAO from chronic high-dose carnitine is under study for cardiovascular relevance; use cycles and washouts as directed.

Stacking Suggestions

• AOD-9604 – For complementary fat-metabolism research
• MOTS-c – Mitochondrial-derived peptide for metabolic homeostasis
• 5-Amino-1MQ – NNMT inhibitor studied for fat-loss support
• NAD+ – For cellular energy and mitochondrial support

Research Sources

PubMed-linked citations for verification. Many studies are animal/in-vitro.

1. L-carnitine supplementation in recovery after exercise. Nutrients. 2018;10(3):349. PMID: 29534031
2. Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans. J Physiol. 2011;589(Pt 4):963-73. PMID: 21224234
3. L-carnitine — metabolic functions and meaning in humans life. Curr Drug Metab. 2011;12(7):667-78. PMID: 21561431
4. Carnitine: a nutritional, biosynthetic, and functional perspective. Mol Aspects Med. 2004;25(5-6):455-73. PMID: 15363636