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Find the Best L-carnitine Supplement of 2025: Reviewing Top Brands

If you dabbled in fitness supplements, you have probably had at least heard the name L-carnitine. Popular among elite athletes and fitness enthusiasts alike, the compound has recently been gaining popularity as a longevity supplement as well. But what is it?

The compound comes in several forms: L-carnitine, acetyl L-carnitine, L-carnitine tartrate, and propionyl-L-carnitine. It is found in various foods and is also synthesized in the body from the amino acids lysine and methionine. The compound is involved in fatty acid transport to mitochondria for oxidation and thus has potential benefits for improving athletic performance, supporting blood sugar control, and weight loss.

If you want to try out L-carnitine and make sure you are taking a high-quality product, we have done the research for you. Read on to find the best L-carnitine supplements on the market as well as the science behind the compound. I will also include my opinion on L-carnitine as someone who has a Master’s in Science and a wellness girly who trains like it’s my actual job and tries to optimize her health in every aspect.

Best acetyl L-carnitine supplement: a shortlist

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Which L-carnitine supplement is the best?

We have chosen ProHealth Longevity Acetyl L-Carnitine as our number one option. We appreciated the third-party testing with the certificate of analysis available on the website. The product is also free from dairy, egg, soy, wheat, gluten, fish, shellfish, tree nuts, or peanuts, making it suitable for a wider audience.

ProHealth focuses on longevity supplements, so its L-carnitine capsules use an acetylated form, which may be absorbed better. We also appreciated the customer feedback; the majority found the product high quality, effective, and easy to take, making it a considerable choice even at a higher price point.

Best acetyl L-carnitine supplement: an overview

Our research team has looked into and helped select each of the supplements on this list. Read on to learn more about our top picks, key features, user experience, and more.

1. ProHealth Longevity — best overall L-carnitine supplement

ProHealth Acetyl-L-Carnitine

ProHealth Longevity Acetyl L-Carnitine capsules pack 500 mg of the compound per capsule. The product is marketed for enhancing cognitive function, supporting cellular metabolism, having antioxidant and cardiovascular benefits, and helping to preserve muscle mass.

The product is third-party tested and manufactured in an FDA-registered, GMP-certified facility. The capsules do not contain dairy, egg, soy, wheat, gluten, fish, shellfish, tree nuts, or peanuts. The brand recommends a daily intake of 1–3 capsules in the morning on an empty stomach or as directed by your healthcare professional.

A container with 120 capsules costs $25.99 ($0.22 per capsule).

Acetyl L-carnitine
500 mg

Who might benefit the most from ProHealth Acetyl L-Carnitine capsules?

People who are looking for a carnitine supplement that has undergone third-party testing and has accessible certificates of analysis may want to consider this product. Those who are looking for capsules with minimal ingredients and free of major allergens may also want to consider this product.

Key features of ProHealth Acetyl-L-Carnitine capsules

  • 500 mg of acetyl L-carnitine per capsule
  • Free of major allergens
  • Third-party tested
  • Certificate of analysis accessible on the website
  • Free U.S. shipping for orders over $30
  • 100-day money-back guarantee

Company review

ProHealth Longevity was founded by Rich Carson, who was diagnosed with chronic fatigue syndrome. On a quest to regain his vitality, Rich entered the supplement field, which led him to want to share his knowledge and experience to help others facing the same issues.

The brand’s motto, “Commerce with Compassion,” stems from its desire to help everyone live their best lives. ProHealth aims to offer the highest-quality supplements on the market and has quickly become one of the most trusted brands in the field. With a focus on longevity, the company offers numerous supplements for those looking to support their health.

Brief summary about ProHealth Acetyl L-Carnitine capsules

We picked this product due to its high quality and straightforward formula, which does not include additional unnecessary ingredients or fillers. Each capsule contains 500 mg of acetyl L-carnitine and is free of major allergens. We also appreciated third-party testing with an easily accessible certificate of analysis online.

2. Momentous — best acetyl L-carnitine for professional athletes

Momentous Acetyl-L-Carnitine

Repping an NSF Certified for Sport badge, Momentous Acetyl L-Carnitine is manufactured to adhere to the highest industry standards and be suitable for professional athletes who undergo doping tests.

The product is marketed to support energy production and brain function as well as provide antioxidant support.

Each capsule contains 500 mg of acetyl L-carnitine. Momentous recommends taking one capsule a day. The brand states that after a few weeks of consistent use, users may start experiencing increased mental clarity and focus.

To ensure adherence to the label and quality, each batch is third-party tested.

A one-time purchase of 60 capsules costs $24.95 ($0.42 per capsule).

Acetyl L-carnitine
500 mg

Who might benefit the most from Momentous Acetyl L-Carnitine?

People who are participating in professional sports may want to choose Momentous due to its NSF certification.

Key features of Momentous Acetyl L-Carnitine

  • 500 mg of acetyl L-carnitine per capsule
  • Third-party tested
  • NSF Certified for Sport
  • Certificate of analysis accessible on the website
  • Free U.S. shipping for orders over $375
  • 30-day money-back guarantee

Company review

My colleagues have done a thorough review of Dr. Huberman’s beloved Momentous supplements. The brand is committed to delivering high-quality products that are not only marketed to increase your well-being but also your physical performance. All products are formulated with the participation of professional athletes and are NSF Certified for Sport, have the Informed Sports certifications, and are also third-party tested for label accuracy. Momentous aims to be a go-to brand that is known for its quality and reputation.

The founder of Momentous, Matt Wan, was around some of the world's most elite trainers from a young age, which influenced his business model and introduced him to the needs of professional athletes. Momentous collaborates with scientists, coaches, dietitians, and other experts in the health and sports field.

Brief summary about Momentous Acetyl L-Carnitine

We appreciate the thorough testing of Momentous’ products, not only is each batch third-party tested, but it also has a certification that it is suitable for professional athletes as it does not contain any restricted substances. Each capsule contains 500 mg of acetyl L-carnitine without any additional ingredients.

3. Nutricost — best affordable acetyl L-carnitine

Nutricost Acetyl L-Carnitine

Nutricost’s Acetyl L-Carnitine capsules contain 500 mg of the compound per capsule. They are made without any unnecessary additional ingredients and are third-party tested to ensure adherence to the label.

The capsules are also non-GMO and free from gluten and soy. The brand recommends one capsule daily.

A one-time purchase of 180 capsules costs $24.95 ($0.14 per serving).

Acetyl L-carnitine
500 mg (per capsule)

Who might benefit the most from Nutricost Acetyl L-Carnitine

People who are looking for a third-party tested acetyl L-carnitine supplement at an affordable price may want to opt for this product.

Key features of Nutricost Acetyl L-Carnitine

  • 500 mg of acetyl L-carnitine per capsule
  • Third-party tested
  • Gluten- and soy-free
  • Non-GMO
  • 60-day money-back guarantee

Company review

Nutricost is a supplement brand offering a wide range of products at an affordable price. The company aims to help reach various health goals while focusing on high-quality products with science-backed ingredients.

Their product range involves vitamins, minerals, and physical performance supplements catering to health enthusiasts, athletes, and people wishing to improve their overall wellness.

Brief summary about Nutricost Acetyl L-Carnitine

Acetyl L-Carnitine capsules by Nutricost are marketed to boost energy and physical performance while remaining relatively affordable. Each serving delivers 500 mg of the active compound.

4. Thorne — best acetyl L-carnitine for sports enthusiasts

Thorne Acetyl-L-Carnitine

Thorne’s Acetyl L-Carnitine, formerly known as Carnityl, contains 500 mg of the compound per serving. Thorne recommends taking 2–3 capsules daily.

The product is gluten-, dairy-, and soy-free and is derived from natural flavors and colors.

Although Thorne has received an NSF Certified for Sport certificate, the third-party testing results for the Acetyl L-Carnitine supplement are not displayed on the product’s page.

A 60 capsule container costs $27.15 ($0.45 per capsule).

Acetyl L-carnitine
500 mg (per capsule)

Who might benefit the most from Acetyl L-Carnitine?

People who are looking for a carnitine supplement that is free from artificial additives may want to choose this product.

Key features of Acetyl L-Carnitine

  • 500 mg of acetyl L-carnitine per capsule
  • Gluten-, dairy-, and soy-free

Company review

Thorne is a health and wellness supplement brand committed to science-backed formulas and high-quality products. The brand emphasizes a personal approach to supplements, so it offers quizzes, tests, and consultations on its website to help customers choose the most suitable products.

Throne has bundles that undergo rigorous testing to be NSF Certified for Sport and suitable for professional athletes.

Brief summary about Acetyl L-Carnitine

Acetyl L-Carnitine by Thorne is marketed to support cognitive function and mood. The formula contains only the main active ingredient, and two or three capsules are recommended, depending on personal needs and medical guidance. However, the third-party testing certificate is not displayed and readily accessible for this product on its page.

5. Double Wood — best customer-rated acetyl L-carnitine

Double Wood Acetyl L-Carnitine

Double Wood has marketed its acetyl L-carnitine capsules to support physical and cognitive performance. L-carnitine, which plays a role in fatty acid oxidation, may boost endurance and stamina during resistance training.

The recommended serving size is two capsules daily, delivering 1,000 mg of the active compound. The product is soy- and gluten-free and non-GMO. To ensure adherence to the label and quality, it is also third-party tested with certificates of analysis available on their website.

A container with 150 capsules costs $19.95 ($0.27 per serving).

Acetyl L-carnitine
500 mg (per capsule)

Who might benefit the most from Double Wood Acetyl L-Carnitine?

Those who value quality and transparency supported by third-party testing and are budget-conscious may consider Double Wood.

Key features of Double Wood Acetyl L-Carnitine

  • 1,000 mg of acetyl L-carnitine per serving
  • Third-party tested
  • Soy- and gluten-free
  • non-GMO
  • Certificate of analysis available on the website

Company review

Double Wood Supplements is focused on producing high-quality, research-backed supplements aimed at mental and physical well-being. The brand has established itself in the field due to its commitment to quality and transparency. All products are third-party tested, and certificates of analysis are available on the website.

Furthermore, the brand believes that health supplements should be accessible to all; hence, their products tend to be more affordable than competitors.

Brief summary about Double Wood Acetyl L-Carnitine

Acetyl L-Carnitine by Double Wood is a minimal ingredient supplement that has undergone thorough third-party testing and has easily accessible certificates of analysis, which we appreciated. The daily two-capsule serving packs 1,000 mg of acetyl L-carnitine.

Comparing the best L-carnitine supplements

BrandCarnitine typeCarnitine amount per servingPrice Price per servingDaily serving
ProHealth LongevityAcetyl L-carnitine500–1,500 mg$25.99$0.221–3 capsules
MomentousAcetyl L-carnitine500 mg$24.95$0.421 capsule
NutricostAcetyl L-carnitine500 mg$24.95$0.141 capsule
ThorneAcetyl L-carnitine1,000–1,500 mg$28$0.472–3 capsules
Double WoodAcetyl L-carnitine1,000 mg$19.95$0.272 capsules

How we choose the best L-carnitine supplements

To shortlist the best L-carnitine supplements we paid attention to the following criteria.

Safety and qualityDoseType of carnitine Price
Third-party tested and cGMP-compliantThe amount of active compoundL-carnitine form usedValue for money
  • Safety and quality. We checked for third-party testing and certificates of analysis to ensure adherence to the label. We also appreciate manufacturers who use cGMP-certified facilities to increase safety and minimize cross-contamination.
  • Dose. We looked at the amount of L-carnitine per capsule and per serving.
  • Type of carnitine. L-carnitine can come in several forms, so we checked each product for the form of carnitine and aimed to include products with similar forms.
  • Price. We looked at price per package and per serving to help you choose a product within your budget.

What is L-carnitine?

Carnitine is an essential nutrient that plays an important role in energy production. In short, L-carnitine transports long-chain fatty acids into the mitochondria, where they can be turned into energy through a complex biochemical chain of events.

It is a naturally occurring amino acid derivative synthesized in the body but also available from foods, primarily red meat, dairy, and some plant products, such as whole wheat. The compound is available in several forms: L-carnitine, acetyl L-carnitine, L-carnitine tartrate, and propionyl-L-carnitine.

The daily requirement is about 15 mg of carnitine, which comes both from food sources and endogenous synthesis. Numerous L-carnitine supplements are available for those wanting to increase their intake. However, most healthy individuals are able to synthesize sufficient amounts of carnitine in their bodies, even on vegetarian diets.

How to decide on the right L-carnitine supplement for you

To choose the best L-carnitine supplement for your needs, you may want to consider the following criteria.

  • Amount per serving. While the recommended daily value for carnitine is not established, supplements typically range between 500 and 1,500 mg per daily serving. Higher doses, such as 3,000 mg a day, may cause side effects such as nausea, vomiting, abdominal cramps, or diarrhea.
  • Quality. Look for third-party testing and certificates of analysis to ensure adherence to the label and quality.
  • Price. Supplements can vary greatly in price, so have a budget in mind before shopping. More expensive does not always mean better.

Benefits of using carnitine supplements

L-carnitine is claimed to have several various health benefits. While some, like improved physical performance and weight loss, have some supporting evidence, others remain inconclusive.

Physical performance

L-carnitine tartrate is the form most commonly used in sports supplements due to its potential to boost exercise performance and recovery and reduce muscle soreness.

A study involving 14 recreational athletes aged 24–28 used a carbohydrate solution with or without 2.0 g of L-carnitine tartrate twice a day for 24 weeks. The supplementation groups showed 11% better work output, 38% higher muscle activation, and 44% lower muscle lactate content than the control groups when performing the same performance trial task.

Another study was done on eighty healthy participants aged 21 to 65. Forty participants received L-carnitine tartrate supplementation for five weeks, while the equal-sized placebo group did not. Both groups completed a maintenance exercise training program that culminated in a high-volume exercise. At the end of the five weeks, the L-carnitine tartrate supplementation groups had improved perceived recovery and soreness and were also able to blunt declines in strength and power. The results were independent of age and gender.

Weight loss

L-carnitine is commonly used to support weight loss due to its potential to boost exercise performance and improve recovery.

One meta-analysis of 9 randomized controlled trials found that subjects who received L-carnitine lost significantly more weight than the control group. However, it is hard to say if both groups adhered to the same diet and exercise regimens and whether L-carnitine or a calorie deficit played a bigger role in weight loss.

Another meta-analysis of 37 clinical trials found that L-carnitine supplementation showed significantly decreased total body and fat mass. However, waist circumference and body fat percentage did not change significantly. Based on the analyzed studies, the authors suggested 2,000 mg per day as a considerable intake.

Cardiovascular health

Although the evidence is still scarce, there is some to suggest that L-carnitine may have some cardiovascular benefits.

A meta-analysis of 13 clinical trials examining adults with acute myocardial infarction who were either given L-carnitine, 2.7 g/day for five days to 6 g/day for 12 months or placebo, concluded that the L-carnitine supplementation group had an overall 27% lower rates of all-cause mortality. However, L-carnitine did not affect the risk of heart failure.

Insulin sensitivity

There is also a small amount of evidence to suggest that L-carnitine supplementation may help reduce insulin resistance. However, most studies have been done in animals or in vitro.

Another meta-analysis looked at five studies including adults with insulin resistance who were given 2–3 g a day of L-carnitine or a placebo. It found that the measures of insulin resistance were improved. The results were more significant when supplementing for 12 months as compared to three, six, or nine.

Neuroprotective properties

While brands tend to market their products for cognitive benefits, there is a lack of scientific evidence to support such claims. Most of the research has been done in vitro or in vivo in animals, however, the few clinical human trials have produced mixed results.

Acetyl L-carnitine may offer some neuroprotection in conditions that cause central or peripheral nervous system injury in adults.

Expert opinion

I hope you enjoyed the honest yet commercial part of the article and reading about the best products on the market. However, if you are anything like me, you probably want a slightly unhinged and totally honest opinion. I have a Master's degree in Science with Biomedical Sciences as my major, so I have a solid background in human physiology and cellular processes. I am also a big fitness and wellness enthusiast who tries to optimize my well-being with science-backed protocols and supplements and trains at least five times per week. So, I get both the struggle of trying to improve your health and performance and understanding the science behind it.

Although carnitine is an essential nutrient, as I mentioned in the article, most healthy individuals who eat meat and dairy can easily synthesize the required (around 15 mg) daily amount of carnitine.

L-carnitine tartrate has scientific evidence for supporting short-term exercise recovery and reducing post-workout fatigue in athletes and healthy individuals. There is also some evidence that daily supplementation with L-carnitine combined with resistance training improved lifting volume in lower body exercise and reduced fatigue, but not upper body strength, after 9 weeks. Most studies did not see an improvement in aerobic capacity (cardio-based exercise performance) or significant body composition changes, maybe because carnitine is mostly stored in muscle.

Regarding weight loss, most studies have only observed L-carnitine to support weight loss in individuals with obesity but not in healthy individuals. It is also hard to determine whether the effects were due to the supplements or whether the participants improved their diet and lifestyles, thereby losing weight.

Essentially, carnitine may benefit people who do not eat meat and dairy, thus struggling to get in enough essential amino acids for its production in their day, or elite athletes. Keep in mind that athletes already follow a workout and nutrition plan made by experts, they also probably prioritize sleep, recovery, and live a pretty healthy lifestyle. For them, L-carnitine tartrate may be that extra bit of recovery support they need. Like a sprinkling of sesame seeds on a stir fry, however, all the other ingredients are already top-class.

For an average individual looking to improve their athletic performance and recovery, proper nutrition, sleep, and mobility exercises would probably offer more significant benefits than taking L-carnitine. The supplement can be beneficial, but it is not a band-aid solution for the areas you are slacking in. So, unless you think buying a supplement will make you more likely to adhere to healthy habits and lifestyle, it is probably not worth it for the average person.

Types of L-carnitine supplements

There are several types of L-carnitine available on the market, and each may have slightly different properties.

  • L-carnitine. The most common and most affordable type. Most studies are done using L-carnitine.
  • Acetyl L-carnitine. The acetylated form of L-carnitine is mostly used in studies for brain disorders and Alzheimer's disease, as well as physical performance and weight loss.
  • L-carnitine tartrate. Most commonly used in sports supplements and studies on physical performance.
  • Propionyl-L-carnitine. Rarely present in supplements, this form is mostly used in cardiovascular health research.

What makes a high-quality L-carnitine supplement?

To ensure the quality of an L-carnitine supplement, look for third-party testing and accessible certificates of analysis on the website. Furthermore, cGMP and NSF certifications also reflect manufacturing quality.

You may also want to prioritize non-GMO products. You should also carefully check for additional ingredients and avoid artificial flavors and colors.

Integrating L-carnitine into your routine

It is always best to consult a healthcare professional before adding a supplement to your regimen. However, here are some general tips for implementing L-carnitine into your routine.

  1. Take with meals. Taking L-carnitine with meals may reduce potential stomach discomfort. It may also be better absorbed when taken with food.
  2. Timing for exercise. If you are taking L-carnitine for athletic performance and recovery, it may be useful to take it 30–60 minutes before a workout.
  3. Consistency. One of the key factors in seeing benefits, if any, is taking L-carnitine consistently.
  4. Dosage. Follow the dosage guidance on the package or as advised by your doctor, and do not exceed the recommended amount.

Best L-carnitine supplement — conclusion

L-carnitine is a popular supplement with potential benefits for weight loss and physical performance enhancement. However, most scientific evidence is still inconclusive.

Most people who eat red meat and dairy get enough carnitine from their diet. However, if you choose to supplement, consult your doctor if possible, and be picky about the supplement you choose. Consider your goals and pick the supplement that most fits your lifestyle and preferences. While brands market some products as having cognitive and neuroprotective benefits, most of the research only provides evidence for L-carnitine potentially supporting weight loss and exercise performance.

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