The best l carnitine supplement will depend on your health goals. For example, if you are looking for improved athletic performance and reduced muscle aches and fatigue, you should choose L carnitine tartrate. If you want better brain health and antioxidant protection, you should choose acetyl L carnitine. Last but not least, many people claim that free carnitine is best to promote fat loss.
Keep in mind, you will get overlapping benefits from all of these three forms of carnitine. Additionally, the form they come in and quality can differ. In this post, learn about the best L carnitine supplement brands, the benefits of L carnitine, and potential risks.
As with anything, make sure to check with your healthcare provider before starting any new supplements or L-carnitine products.
Table of Contents
Criteria for choosing the best L carnitine
There are several considerations that went into choosing the best L carnitine supplements for this post. Here is a review of these factors:
- Purity: above all, pure L-carnitine is the most important quality measure for choosing L-carnitine supplements. As such, supplements that have questionable additives or unproven ingredients were left off of this list. That is why L-carnitine powder was chosen as the best L-carnitine because there are zero additives in the ones here.
- Third-party inspection: the companies that voluntarily undergo inspections for quality and purity made the list here. Specifically, companies that have Good Manufacturing Practices certification were chosen here when possible because they have independent testing on all of their supplements.
- Cost: price is an important consideration for many people, so the supplements that rank highest on this list are also more cost-effective.
- Effectiveness: by evaluating rating reviews and company reputation, the effectiveness of each brand was determined for this list.
- Additives: supplements with unnecessary or questionable additives were left off of this list. For example, some supplements contain added calcium. Not all people benefit from additional dietary calcium, so these were left off of the list as well.
- Individual health goals: some L-carnitine benefits brain health the most, while others seem to benefit exercise and body sculpting more. Both were taken into consideration when including the supplements here.
Best L Carnitine Supplements Overview
If you don’t have time to read the whole post, here is a summary of the top 4 Recommended L carnitine brands. Additional brands and forms are included further in the post.
- Best overall: Nutricost Acetyl L Carnitine powder stands out as the best L carnitine because it contains pure acetyl L carnitine with absolutely no additives or fillers. Additionally, it is the best L carnitine for brain health and the most budget-friendly. In other words, it checks all the boxes for quality and effectiveness.
- Best for athletic performance: Now L Carnitine Tartrate powder is the best for muscle health and exercise performance because it contains pure L carnitine tartrate, known to help with reducing muscle fatigue and enhancing exercise. It also has no additives or fillers and is vegetarian and vegan.
- Best doctor-recommended brand Douglas Laboratories Acetyl L carnitine capsules are pharmaceutical grade L carnitine supplements that meet strict manufacturing practices and are highly trusted by healthcare professionals.
- Best for metabolism: Dr. Martin’s Nutrition L-Carnitine Natural Free Form While all L carnitine forms are linked to improved weight loss and body composition, this natural, free-form carnitine supplement gets overwhelmingly positive reviews for helping aid with weight loss and reducing body fat.
Best L Carnitine Overall
Nutricost acetyl L carnitine powder is the best L carnitine supplement because it contains the form of carnitine, known as acetyl L carnitine, that is best for brain health. It is also the most budget-friendly brand while also meeting all the strict quality criteria. For example:
- It contains no additives or fillers
- Free of allergens like dairy, wheat, soy, gluten, corn
- Has overwhelmingly positive reviews
- Is the best budget: a great value with 100 servings per container and under $20
- Each serving contains 1 gram of pure acetyl L-carnitine powder or the equivalent of 1000mg servings plus no additives
- GMP-certified and GMP-compliant in an FDA-registered facility
If you want to be assured that you are getting pure L carnitine, make sure to choose the powder form like this one.
Cons: carnitine powders tend to clump up because they are hygroscopic-which means they attract water to them. Some people complain that the taste of mild fishiness is a characteristic taste of L-carnitine, however. To most people, the flavor is mild and can be disguised in an electrolyte drink.
Best L Carnitine for Athletic Performance
NOW Supplements, L-Carnitine (L-Carnitine Tartrate) pure powder is the best L carnitine for physical performance. This is because it contains the form of L-carnitine called L-carnitine tartrate, which is absorbed quickly into the body [R]. It is also a vegan L carnitine form, making it suitable for both vegetarians and vegans.
Containing nothing but pure L-carnitine tartrate, Now L-carnitine delivers exactly what you want without the risk of any harmful additives as well. Other benefits of this supplement include:
- Allergen-free, including dairy-free, egg-free, soy-free, corn-free, nut-free, and gluten-free
- GMP certified, meaning third-party-inspected at all steps of manufacturing
- A USA company
- Contains the trademarked form of carnitine called Carnipure, which means it is guaranteed pure L-Carnitine
- Reasonably priced
Unlike many carnitine supplements that are promoted for athletic performance, this one stands out because it is pure. Most carnitine on the market contains fillers, additives, or undesirable compounds that may deter you from the benefits you are looking for. Powder forms of carnitine like Now Supplements are free from these.
Cons: some people say this supplement product tastes sour or bitter like lemons, but that it is not unpleasant and easy to disguise.
Best Doctor-Recommended L-Carnitine
Douglas Laboratories Acetyl-L-Carnitine 500 mg- Trusted by healthcare providers, Douglas Laboratories Acetyl L-Carnitine is pure acetyl L-carnitine with 120 capsules per bottle. Each capsule contains 500 mg of carnitine.
- Surpasses GMP standards and manufacturing regulations.
- A trusted company for 65 years by healthcare professionals
- Allergen free
- Contains 120 servings at 500 mg per serving
Other ingredients include cellulose, hydroxypropyl methylcellulose, vegetable stearate, and silica.
Douglas Laboratories has a large team of medical advisors who help provide input on their formulations and supplements. Packaging and bottles are fully recyclable and the company supports the Terracycle recycling program which is working to reduce global waste.
Capsule forms like this L carnitine work well for people who don’t want to mess with powders or are sensitive to the taste of L-carnitine.
Cons: more expensive than some carnitine supplements.
Best L Carnitine Capsule for Metabolism
Dr. Martin’s Nutrition L-Carnitine Natural Free Form L Carnitine supplement gets the highest reviews for effectiveness related to fat burning and weight loss. While no research specifically states that free-form L carnitine is better than other types of carnitine for this purpose, thousands of reviewers seem to agree that this brand does the trick.
Another major perk of this brand is the low cost and consistent quality as rated by reviewers. It’s my personal go-to carnitine for its convenient capsules. Its features include:
- Best L carnitine capsule for budget and quality.
- Best L Carnitine Capsules because it is pure L-carnitine
- 100 servings per container and less than $10 per month supply
- Contains L-carnitine 500 mg per capsule
- Made in the United States
- Free L-Carnitine
- other ingredients: gelatin, magnesium stearate, and silica
People even claim it’s good for their fibromyalgia pain and for thyroid disorders. While all capsules contain some amount of stabilizers and fillers, this supplement contains natural silica, which is even found in water. Magnesium stearate is also generally recognized as safe.
Also a great supplement for mental clarity and helps reduce fatigue for many people.
Cons: capsules are large, so some people may have a difficult time swallowing them.
Best L carnitine gummies
Snap L-Carnitine Tartrate Gummy 30 servings per container
- An all-natural pre-workout gummy that may help improve exercise stamina
- L-carnitine is an antioxidant so it supports post-workout recovery
- L carnitine is known to support a healthy metabolism, prevent fatigue, and aid repair in nearly every cell in the body.
- 90-day guarantee of product satisfaction
- Allergen free
- Its other ingredients are safe and natural, and include Isomalt, Maltitol, Pectin, Natural Berry Flavors, Black Carrot Extract, Adipic acid, Citric acid, and sodium citrate
- Manufactured in an FDA-registered and GMP-certified facility
Cons: As with most gummy supplements, the dose is lower than most other carnitine supplements. It is also more expensive than many of the supplements of L carnitine available today. Additionally, if you eat too much, the sugar alcohol content could have a laxative effect.
Best Liquid L-Carnitine
NOW Sports Nutrition, L-Carnitine Liquid, is a very popular liquid form of L-carnitine because it is triple strength 3000 mg per serving with citrus flavor and overwhelmingly positive reviews. Although this supplement does contain some calcium and potassium, there are no appreciable amounts of it. For this reason, this product made the list. Additionally, this product gets overall very good reviews for taste and some reviewers say it tastes tropical.
- A 16-ounce bottle with 32 servings per bottle- over 90 servings if you use a lower dose
- Ingredients: Vitamin B-12 (as Cyanocobalamin), Vitamin B-5 (from D-Calcium Pantothenate), Calcium, Potassium, L-Carnitine (L-Carnipure™) (Free-Form Base), Stevia rebaudiana Extract (Leaf) (min. 80% Rebaudioside-A)
- Other Ingredients: Distilled Water, Vegetable Glycerin, Malic Acid, Citric Acid, Natural Orange Flavor, Natural Vanilla Flavor, Potassium Sorbate (as preservative) and Lemon (Citrus limon) Oil.
- Free of allergens, and no sugar, salt, starch, yeast, wheat, gluten, corn, soy, milk, egg, shellfish or artificial colors/flavors.
- Vegetarian/Vegan Product
- More affordable than Designs for Health
Important consideration when buying Now L-carnitine liquid: You should start with a third of a tablespoon (1 teaspoon) dose if you are new to taking carnitine
Cons: Is in a plastic bottle instead of a glass bottle and contains stevia, which some people dislike. The form of vitamin B12 would be better if it was methylcobalamin.
Notes on taking: You should start with ⅓ the recommended dose for people who are new to carnitine.
LivOn Lypo Spheric acetyl l carnitine liposomes help to improve carnitine absorption according to the company. No evidence specifically describes the benefits of lypo spheric carnitine, but liposomes do help improve the absorption of many nutrients, including vitamin C.
This supplement’s features include:
- A new method of enhanced Acetyl L-Carnitine is Liposomal Encapsulation Technology. This means it allows your body to absorb more Acetyl L-Carnitine.
- Like other acetyl-L carnitine, it promotes a healthy brain, nerve cell function, and neurological health
- Supports healthy workouts and muscle health
- Active ingredients: phosphatidylcholine and acetyl L-carnitine
- Other ingredients: purified water, alcohol, potassium hydroxide, xanthan gum
- Excellent source of choline
- The formula contains NO: Gluten, Dairy, Sugar, or Hexane
- Approved for Zone/Paleo diets
- Comes in convenient single-serve packets
- A certificate of analysis is available from the LivOn Lab per request
Add a small amount of water or your favorite cold beverage and consume.
Cons: more expensive than most brands. Contains soy because it has phospholipids in it.
What is L carnitine?
L carnitine is an amino acid compound that is made from two essential amino acids called lysine and methionine. These form amino acids can be low with people on restrictive diets, especially vegans.
Experts know that L-carnitine is critical for health because it helps transport fatty acids into our energy-producing parts of the cell called the mitochondria.
This means that L-carnitine is essential for mitochondrial health, for helping make energy, and even for promoting fat loss and lean muscle growth.
While our cells make L carnitine, there are a lot of reasons that you may not have enough L carnitine to feel your best [R]. In other words, L carnitine is a conditionally essential amino acid and may require supplementation for some people.
Examples of reasons that you may be low in carnitine are:
- Being a vegan or vegetarian
- Having a restrictive diet or avoiding meat, chicken, fish, liver, eggs, or animal sources of foods
- Kidney dialysis
- Inherited carnitine deficiency
- Ketogenic diets
- Seizure medications
- Some cancer medications
Benefits of L carnitine supplements
As a critical component of cellular energy, L-carnitine has the potential to help with a vast array of health conditions. Here is an overview of current research and how L-carnitine may help with each of these.
Increased muscle mass
L carnitine helps to improve protein muscle content through its beneficial effects on metabolism [R].
It may help retain muscle because it acts as an antioxidant in muscle tissue, although no one knows for sure how carnitine works to keep muscle strength.
Reduces body fat
A large systematic review of 37 research studies found that supplemental L-carnitine reduces body fat mass and body weight, especially in overweight and obese adults [R].
This logically makes sense because L-carnitine is critical to helping burn fat within the mitochondria of our cells.
These results were published in the peer-reviewed Clinical Nutrition European Society for Enteral and Parenteral Nutrition journal.
However, a reduction in body fat and body weight as well as BMI is only seen in people with elevated BMI levels over 25 kg/m2.
In other words, L-carnitine is more likely to help with weight loss if you are overweight or obese.
Improves exercise measurements
An appealing feature of L-carnitine supplements is that it may help improve your exercise efforts.
In fact, adding L-carnitine to exercise routines helps to reduce muscle aches and soreness. All the while, it also increases the body’s total antioxidant capacity and reduces post-exercise pain from resistance exercise [R, R].
L-carnitine may also enhance aerobic exercise capacity by increasing maximal oxygen uptake and increasing power output [R, R]. The dose needed to improve exercise tolerance and capacity is typically between 2-4 grams per day.
All told, it’s no wonder that people turn to L-carnitine supplements as a stimulant-free sports nutrition supplement and to help improve workouts.
Reduces some kinds of pain and fatigue
As an antioxidant and critical component of cellular energy, L-carnitine also helps alleviate some types of chronic pain and fatigue as well. Impressively, L-carnitine even helps to alleviate nerve pain called neuropathy [R]. This fascinating supplement promotes nerve regeneration.
By reducing inflammation, L-carnitine may also help to reduce pain in diseases like osteoarthritis [R].
People with chronic fatigue syndrome also tend to have low L-carnitine levels in their bodies [R]. While not a lot of research has focused on the effects of L-carnitine on energy levels, one study showed a reduction in fatigue with the use of L-carnitine in multiple sclerosis patients [R].
Additionally, many people who take L-carnitine have positive testimonials about how it improves their energy levels.
L-carnitine may even help boost brain serotonin and other neurotransmitters, making it a possible benefit for people suffering from depression or mood disorders [R]. In fact, a systematic review of 11 studies found acetyl L-carnitine beneficial for depression with similar effectiveness to established treatments [R].
Additionally, one study found that memory loss was slowed in people with dementia who received L-carnitine compared to placebo over a 6-month period [R].
The heart requires a lot of energy known as ATP to pump. As a critical aspect of energy production, L-carnitine can help certain heart conditions.
In 17 clinical studies of patients with heart failure, L-carnitine supplements helped improve cardiac output, and cardiac function, and decreased a marker of heart failure severity called BNP (brain-type natriuretic peptide) [R].
Impressively, L-carnitine is related to a 65% reduction in abnormal heart rhythm called ventricular arrhythmias in people who had previously suffered from heart disease [R]. Angina, or heart pains, were reduced by 40% compared to placebo as well.
However, not all heart conditions may benefit from L-carnitine supplementation, so make sure to first check with your doctor before starting L-carnitine.
Lack of carnitine may slow down the gut movements of the intestines. This means that if you are low in carnitine, you may be more likely to suffer from constipation. Some research shows that L-carnitine helps to increase the health of the gut by reducing the growth of harmful bacteria called Clostridium species [R].
Although much more research is needed to determine if L-carnitine helps reduce constipation, many reviewers state that it increases their bowel movement frequency.
Carnitine helps the intestines to absorb fat and even helps to digest fibers to promote a healthy microbiome as well [R].
May improve eye health
Carnitine is present in eye tissue and may protect eye health. This is because research shows that L-carnitine may help reduce symptoms of age-related macular degeneration, glaucoma, and dry eye syndrome [R, R].
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May help with fertility
Men with infertility may benefit from L-carnitine supplementation because it increases sperm quality according to 1 small study [R]. Although more research is needed, L-carnitine holds promise in this area.
Risks of L-carnitine
L carnitine supplements are very safe and cause little to no side effects.
Occasionally, nausea or dyspepsia can happen at high doses [R].
There is some concern that L carnitine can raise the levels of a compound called TMAO (Trimethylamine-N-Oxide) [R].
However, L-carnitine supplements do not appear to raise the risk of cardiovascular disease per se. Additionally, L-carnitine has some protective effects for the heart [R].
In fact, low l-carnitine levels are related to increased rates of cardiovascular disease [R].
The best time to take L-carnitine
The most important consideration when taking L-carnitine is to take it on an empty stomach because it will compete for absorption with other compounds in your diet [R].
It is best to take L-carnitine before you exercise because it absorbs rapidly. Many people also take it in the morning to help provide an energy boost.
Forms of L-carnitine
As mentioned earlier, the form of carnitine you choose may have a greater health impact on certain health goals than others. Here is an overview of how to choose your L-carnitine supplements.
- Acetyl L carnitine- is an ester form of L-carnitine that is best for brain health because it easily crosses the blood-brain barrier. This form of carnitine is also referred to as ALCAR. It also is a stronger antioxidant than other forms of carnitine [R]. Slightly slower to absorb, so it is less often used for exercise-enhancing. But it also works great for exercise performance and muscle health too.
- Free L-carnitine- is thought to be optimally absorbed into the body, although this is a health claim on labels that hasn’t been proven in research.
- L-carnitine tartrate (also known as L-carnitine L-tartrate) is most often used for exercise because of its quick absorption. It also has benefits for promoting weight loss and fat burning.
- D-carnitine is best to avoid this form of carnitine because it interferes with natural carnitine in the body [R].
- Propionyl carnitine is an ester form of L-carnitine. It is harder to find as a supplement, but research shows it may be useful for improving circulation, heart health, and exercise enhancement [R].
- Carnitine HCL: this form of carnitine is used in supplements, although no research specifically states that it is better than any other form of carnitine.
Disclaimer: The information on this website has not been evaluated by the Food & Drug Administration or any other medical body and is shared for educational purposes only. While The Healthy RD’s posts are backed by research, you are unique. So you must seek care from your own dietitian or healthcare provider. This post is not meant to diagnose or treat any conditions. Consult your doctor or healthcare provider before making changes to your supplement regimen or lifestyle.
Heidi Moretti, MS, RD is The Healthy RD. A registered dietitian for 23 years as well as a book author of the new book Gut Fix and The Whole Body Guide to Gut Health, Heidi has a passion for functional nutrition and natural medicine. She has researched supplements and natural medicine throughout her career. One of her biggest loves is helping people gain function and vitality by tackling the root causes of illness.