L-Carnitine Supplements Compared
We currently recommend 4 L-Carnitine supplements. The table below lines them up on what each label actually states: the form, how much is in a serving, how many capsules or servings are in the bottle, and how the extract is standardized. Under the table, each product has its own section on when and how to take it and what it pairs well with.
L-carnitine is a nutrient your body makes from the amino acids lysine and methionine, and gets from red meat. It carries fatty acids into the mitochondria to be burned for energy. Acetyl-L-carnitine (ALCAR) crosses into the brain more readily and is the form usually chosen for focus; L-carnitine tartrate is the form most studied for exercise recovery.
| Product | Form | Serving | Count | Standardization | Also notable | Buy |
|---|---|---|---|---|---|---|
| NOW Acetyl-L-Carnitine | Capsule | 500mg | 200 | Acetyl-L-carnitine | Non-GMO, Kosher | Amazon |
| Nutricost Acetyl-L-Carnitine | Capsule | 500mg | 180 | Acetyl-L-carnitine | Third-party tested | Amazon |
| Nutricost L-Carnitine Tartrate | Capsule | 1,000mg | 120 | L-carnitine tartrate | Third-party tested | Amazon |
| NOW L-Carnitine | Tablet | 1,000mg | 100 | L-carnitine | Vegetarian | Amazon |
How to choose a L-Carnitine supplement
Typical dosage: Acetyl-L-carnitine is typically taken at 500mg to 1,500mg per day, and L-carnitine or L-carnitine tartrate at 1,000mg to 2,000mg per day. Larger amounts are often split into two doses with food to avoid stomach upset.
Things to know: High doses can cause nausea, diarrhea or a fishy body odor. Talk to a doctor first if you have an underactive thyroid or take thyroid medication, take blood thinners such as warfarin, have a history of seizures, or have kidney disease.
Serving sizes aren't always comparable between products. A concentrated extract and a whole-herb powder can list very different milligram amounts for a similar effect, so compare the standardization column, not just the serving.
L-Carnitine
NOW Acetyl-L-Carnitine
500mg acetyl-L-carnitine per veg capsule, Non-GMO and Kosher. 200 capsules.
- Form
- Capsule
- Serving
- 500mg
- Count
- 200
- Standardization
- Acetyl-L-carnitine
- Also notable
- Non-GMO, Kosher
When to take it
Take it in the morning or early afternoon. Some people find acetyl-L-carnitine mildly stimulating, so avoid taking it late in the day.
How to take it
Each veg capsule is 500mg. Most people take 1 to 3 capsules a day (500mg to 1,500mg), split across the day. Take it with food if it upsets your stomach.
What to combine it with
Acetyl-L-carnitine is the form usually chosen for focus, and is sometimes stacked with Lion's Mane. If you take thyroid medication or blood thinners, talk to your doctor first.
L-Carnitine
Nutricost Acetyl-L-Carnitine
500mg acetyl-L-carnitine per capsule, third-party tested. 180 capsules, 180 servings.
- Form
- Capsule
- Serving
- 500mg
- Count
- 180
- Standardization
- Acetyl-L-carnitine
- Also notable
- Third-party tested
When to take it
Take one capsule in the morning or early afternoon. Avoid late evening if you find it stimulating.
How to take it
Each capsule provides 500mg of acetyl-L-carnitine, and the label serving is one capsule. Take it with water, and with food if you have a sensitive stomach. Higher amounts (up to around 1,500mg a day) are usually split into separate doses.
What to combine it with
A common focus routine pairs it with Lion's Mane. Don't combine it with other carnitine products without counting the total dose.
L-Carnitine
Nutricost L-Carnitine Tartrate
1,000mg L-carnitine tartrate per serving (two capsules), third-party tested. 120 capsules, 60 servings.
- Form
- Capsule
- Serving
- 1,000mg
- Count
- 120
- Standardization
- L-carnitine tartrate
- Also notable
- Third-party tested
When to take it
Take it daily. Many people take it with a meal on training days, as L-carnitine tartrate is the form most studied for exercise recovery.
How to take it
The label serving is two capsules (1,000mg of L-carnitine tartrate). Take it with food; some research suggests carnitine is taken up into muscle better alongside carbohydrates. Up to 2,000mg a day is common, split into two doses.
What to combine it with
Mainly used as a workout supplement rather than a nootropic. If your goal is focus, acetyl-L-carnitine is usually the better choice. Avoid stacking several carnitine products.
L-Carnitine
NOW L-Carnitine
1,000mg L-carnitine per tablet, vegetarian (non-animal sourced). 100 tablets.
- Form
- Tablet
- Serving
- 1,000mg
- Count
- 100
- Standardization
- L-carnitine
- Also notable
- Vegetarian
When to take it
Take it once or twice a day, with meals.
How to take it
Each tablet provides 1,000mg of L-carnitine. Take one with a meal, or two split between meals if you want 2,000mg a day. Taking it with food reduces the chance of stomach upset.
What to combine it with
Plain L-carnitine is a general-purpose form; for focus, many people prefer acetyl-L-carnitine instead. Talk to your doctor first if you take thyroid medication or blood thinners.
Read more about L-Carnitine
Acetyl-L-Carnitine vs. L-Carnitine: Which Form Should You Buy? →
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