Amino Acid
L Carnitine
Also known as: LC, L-Carnitine HCl, L-carnitine hydrochloride, Levocarnitine HCl
L-carnitine is a naturally occurring compound synthesized from amino acids that plays a crucial role in transporting long-chain fatty acids into mitochondria for energy production. Evidence supports modest benefits for exercise performance and recovery in carnitine-deficient individuals, though benefits in healthy populations are limited.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every L Carnitine product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Nootropics Depot Acetyl L-Carnitine HCL (ALCAR) Capsules | 94 A | $0.22 |
| 2 | Nutricost Acetyl L-Carnitine Powder | 94 A | $0.08 |
| 3 | Nootropics Depot Acetyl L-Carnitine ALCAR Powder | 94 A | — |
| 4 | Pure Encapsulations Acetyl-l-Carnitine | 92 A | $0.75 |
| 5 | Integrative Therapeutics Acetyl L-Carnitine | 87 A | $1.35 |
| 6 | Life Extension Optimized Carnitine | 87 A | $0.78 |
| 7 | BulkSupplements L-Carnitine HCl Powder | 86 A- | $0.04 |
| 8 | Momentous Brain Drive | 86 A- | $1.50 |
| 9 | Bluebonnet Nutrition ACETYL L-CARNITINE 500 mg | 85 A- | $0.68 |
| 10 | Integrative Therapeutics ProThrivers Wellness Brain | 83 A- | $1.07 |
| 11 | Pure Encapsulations RevitalAge Ultra | 81 A- | $2.60 |
| 12 | Pure Encapsulations RevitalAge Nerve | 80 A- | $1.22 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much L Carnitine should I take?
The typical range is 1-3g daily. 3 months (sperm development cycle)
When should I take L Carnitine?
Divided doses. Either way.
Which form of L Carnitine is best?
L-Carnitine L-Tartrate — Good for fertility. Other forms in the catalog: Acetyl-L-Carnitine, Combination, Powder, Capsules, Tablets, Liquid.
Is L Carnitine safe?
Commonly reported: Fishy body odor, GI upset, Nausea. Serious warnings: May increase TMAO (gut-heart), Seafood smell. Dialysis patients use with caution
Which L Carnitine supplement scores highest?
Nootropics Depot Acetyl L-Carnitine HCL (ALCAR) Capsules, at 94/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Primary uses
- Sperm motility
- Sperm energy
- Male fertility
- Mitochondrial function
- Energy metabolism and fat oxidation
- Exercise performance and endurance
- Muscle recovery
- Cardiovascular health
How it works
- Provides energy for sperm motility
- Supports sperm mitochondria
- May improve sperm parameters
- Acetyl form crosses BBB
Dosage
- Typical range
- 1-3g daily
- Timing
- Divided doses
- With food
- Either way
- Duration
- 3 months (sperm development cycle)
- Special populations
- Male fertility, sperm motility issues, oligospermia
Forms
- L-Carnitine L-Tartrate
- Acetyl-L-Carnitine
- Combination
- Powder· 70/100
- Capsules· 70/100
- Tablets· 70/100
- Liquid· 70/100
Safety
Common side effects
- Fishy body odor
- GI upset
- Nausea
Contraindications
- Seizure disorders (may lower threshold)
Products containing L Carnitine
Top-scoring supplements in our catalog that list L Carnitine on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Good evidence for male fertility, particularly sperm motility
Grade B: Some human trials support key claims; further confirmation needed.
L Carnitine compared head-to-head
Related in Amino Acid
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.