Overview
L-Carnitine (injectable) is an essential amino acid derivative that plays a non-negotiable role in shuttling fatty acids into cellular mitochondria for energy production.
What problem it targets: It targets sluggish fat metabolism, low workout endurance, high post-exercise muscle soreness, poor brain focus, and androgen receptor insensitivity.
What It Does
• Shuttles fatty acids into the mitochondrial furnace: Transports long-chain fatty acids across the inner mitochondrial membrane via CPT-1 so they can be burned for fuel (beta-oxidation).
• Bypasses terrible oral bioavailability: Oral carnitine has less than 15% bioavailability and produces TMAO in the gut; injectable L-carnitine ensures 100% systemic utilization without gastrointestinal upset.
• Upregulates androgen receptor density: Clinical studies show regular L-carnitine administration increases the density of androgen receptors on muscle cells, enhancing muscle protein synthesis.
• Realistic expectations: Daily injectable doses (200–600 mg) paired with carbohydrates or exercise dramatically enhance muscle fullness, sweat rates, fat burning, and recovery over 3 to 4 weeks.
Reconstitution
| Vial size | BAC water or Solvent | Concentration |
|---|
| 600 mg | + 0.60 mL | 1000 mg/mL |
| 1200 mg | + 1.2 mL | 1000 mg/mL |
Protocol
| Phase | Frequency | Dose | Notes |
|---|
| Standard | M/W/F | 500–1,000 mg | Community dose. |
| High | M/W/F | 1,200–1,500 mg | Fat oxidation range. |
| Pre-WO | Before exercise | 500 mg | Timing-specific. Cycle: 8–12 weeks on / 4 weeks off. Max: ongoing maintenance with quarterly 2-week breaks. Timing: Pre-workout (preferred, 30–60 min before) or daily anytime. By sex: Unisex fat-metabolism cofactor, same protocol for men and women; no meaningful sex difference. Generally well tolerated. |
Handling & Stacking
Injection site
IM preferred or SubQ. Upper outer thigh for volume.
Storage
- Freeze-dried: -4°F.
- Reconstituted: 36–46°F.
- Best used within 28 days.
- There's no real community potency figure here; L-carnitine's a stable small molecule, so the honest limit on a reconstituted multidose vial is sterility at ~28–30 days refrigerated, not potency.
Side effects
Fishy odour (TMAO conversion). Generally well tolerated.
What to expect
- Exercise performance and fat utilisation improvement within 2–4 weeks.
- Reduced post-workout fatigue.
- Works best in caloric deficit or with GLP- 1 therapy.
- Supply math 600mg → 60 vials | 1200mg → 30 vials (8-wk @ 1500 mg × 3/wk)
Pairs well with
GLP-1 agonists (fat oxidation during caloric deficit); LC526 / LC216 (lipotropic stack); NAD+ (mitochondrial stack)
Avoid
Hypothyroid medication, separate by 4 hrs. Warfarin (may potentiate)
Safety & Patient Education
Contraindications
Component allergies (B12, riboflavin, lecithin, choline, methionine, lidocaine) Hypothyroid medication, separate by 4 hours Severe hepatic impairment (choline metabolism) Pregnancy and lactation, specific compounding required Bleeding disorders or anticoagulants (relative), bruising risk Severe renal impairment (carnitine accumulation) Seizure disorder (case reports of seizure exacerbation) Hypothyroidism without dose separation
Warnings
Compounded products, composition varies; request the pharmacy’s COA B12 (cyanocobalamin) contains cobalt, allergy possible Methionine elevates homocysteine in some individuals L-Carnitine: TMAO conversion concern in CV disease (controversial, baseline lipids) Injection-site reactions common with phosphatidylcholine
Drug interactions
Warfarin: L-carnitine and choline blends can potentiate, monitor INR if combining Levothyroxine: separate by 4 hours, choline/B-vitamins affect absorption Anticoagulants / antiplatelets (DOACs, aspirin, clopidogrel): bruising risk with phosphatidylcholine Insulin / antidiabetics: B-complex may shift glucose, recheck log if dosing changes Methotrexate, trimethoprim, phenytoin: deplete folate / B12; coordinate with prescriber Lidocaine blends (LC526): avoid other caines same session, additive cardiac effects Stimulants / phentermine: additive CV load with high-dose lipotropics, monitor BP/HR Warfarin (potentiation), thyroid medication (separate by 4 hours)
Labs
Compound-specific: CBC + CMP baseline; no compound-specific markers routinely required Baseline B12, folate, MMA, homocysteine (methylation markers) TSH at baseline (B12 deficiency masks hypothyroidism) Liver enzymes (choline metabolism) Hematocrit (B12 raises RBC, polycythemia risk in some)
Stop criteria
New seizure activity
Patient education
Fishy odor from choline/L-carnitine is normal, not allergic Inject slowly to reduce stinging Don’t use with warfarin without physician guidance (potentiation risk) Request exact ingredient list and concentrations from your compounder
References
researchdosing · peptidedosages · DailyMed · PubMed · ClinicalTrials · Drugs.com
