Carnitine: The Best Forms to Use For Exercise Performance, Brain Health, and More

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Along with providing information on whether carnitine supplements might be right for you, this article also links to Fullscript where you can buy various forms of carnitine supplements online through Fullscript’s secure healthcare formulary and get free shipping and 20% off the retail price of professional-grade supplements.

Carnitine, a naturally occurring amino acid, plays a crucial role in energy production in our bodies. It comes in various forms, each with its unique properties and health advantages. In this article, we cover the nuances of L-Carnitine, Acetyl-L-Carnitine, and other forms uncovering how these supplements can support different aspects of health and wellness. From enhancing physical performance and aiding in weight management to supporting brain health and improving cardiovascular function, carnitine supplements offer a range of benefits.

Whether you’re an athlete looking for an edge in your training, someone interested in cognitive health, or seeking ways to support heart health, this article will provide valuable insights into how carnitine can be a beneficial addition to your health regimen. Let’s embark.

What Is Carnitine?

Carnitine is a nutrient that plays an essential role in the production of energy in our bodies. It is primarily responsible for transporting long-chain fatty acids into the mitochondria, which are the energy-producing centers within our cells. Once inside the mitochondria, these fatty acids are broken down through a process called beta-oxidation to generate ATP (adenosine triphosphate), the primary energy molecule for all cells.

In simpler terms, carnitine acts like a shuttle service, carrying fatty acids into the cell’s power plants (mitochondria), where they are transformed into energy. This process is vital because it allows our bodies to use stored fat as a source of fuel, particularly during periods of fasting, exercise, or increased energy demand.

Carnitine can be obtained through dietary sources such as meat, fish, and dairy products. Our bodies also have the ability to produce carnitine from the amino acids lysine and methionine, with the help of vitamins and minerals like vitamin C, niacin, vitamin B6, and iron.

What Are The Health Benefits of Each Type of Carnitine?

Carnitine supplements are available in several forms, each with specific properties and potential benefits. Some common forms of carnitine sold as supplements include:

  • L-Carnitine: This is the most common and biologically active form of carnitine, which is naturally found in our bodies. L-carnitine is often used for improving exercise performance, weight loss, and supporting heart health.
    • Exercise performance: L-carnitine supplementation may improve exercise capacity and reduce muscle fatigue. [PMC8704793]
    • Women’s Fertility: The decline of mitochondrial function with age has been proposed to be a main cause of decline of embryo quality and fertility. L-carnitine is thought to prevent cell damage and promote β-oxidation. Research from a study of women receiving L-carnitine in addition to fertility treatments improved the quality of oocytes. [PMID: 29378447]
  • Acetyl-L-Carnitine (ALCAR): This form of carnitine has an acetyl group attached to it, allowing it to cross the blood-brain barrier more easily. As a result, ALCAR is often used for cognitive support, including memory enhancement, mood improvement, and neuroprotection.
    • Cognitive support: ALCAR may help improve cognitive function, memory, and mood in various populations, including older adults and individuals with cognitive impairment.
    • Alzheimer’s: Clinical research shows that taking acetyl-L-carnitine 1.5-3 grams daily for 3-12 months might slow the rate of Alzheimer’s disease progression and improve memory, some measures of cognitive function, and behavioral performance. A review of the studies on Acetyl-L-Carnitine showed beneficial effects on both the clinical scales and the psychometric tests by 3 months and increased over time. [PMID: 12598816]
    • Diabetic Neuropathy: ALCAR has shown potential in supporting nerve health and alleviating neuropathic pain. Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: an analysis of two randomized placebo-controlled trials. [PMID: 15616239]
  • Propionyl-L-Carnitine (PLC): PLC has a propionyl group attached to the carnitine molecule, which is thought to enhance its ability to support heart health. It is often used for conditions related to the cardiovascular system, such as angina, congestive heart failure, and peripheral vascular disease.
    • Peripheral Artery Disease: Propionyl-L-Carnitine supplementation helps improve blood flow and reduce symptoms in patients with peripheral arterial disease and chronic heart failure. Propionyl-L-carnitine at a dose of 1 to 2 g/day, was shown to be effective in intermittent claudication in a randomized trial. [PMID: 7594063] [PMC8413087].
  • L-Carnitine L-Tartrate (LCLT): This form is a combination of L-carnitine and tartaric acid. LCLT is often used for sports performance and recovery, as some studies suggest it may help reduce muscle damage and soreness after exercise.
    • Exercise recovery: LCLT supplementation may help reduce muscle damage, soreness, and inflammation after exercise, leading to improved recovery. [PMID: 11788381]

Food Sources of Carnitine

Rich sources include red meat, poultry, fish, and dairy products, with beef and pork being particularly high in carnitine content. While plant-based foods contain minimal amounts, some, like avocados and soybeans, provide small quantities.

Food SourceServing SizeCarnitine Content (mg)
Beef (cooked)3 ounces (85 grams)81 mg
Pork (cooked)3 ounces (85 grams)24 mg
Chicken (cooked)3 ounces (85 grams)3-5 mg
Fish (cod, cooked)3 ounces (85 grams)4-7 mg
Whole Milk1 cup (240 ml)8 mg
Cheddar Cheese2 ounces (56 grams)2 mg
Ice Cream1/2 cup (118 ml)3 mg
Avocado1 medium (200 grams)2 mg
Soybeans (cooked)1/2 cup (90 grams)2 mg
Bread (whole wheat)2 slices (56 grams)0.5 mg

In comparison to food sources, carnitine supplements come in several forms, including L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine. These supplements are used to address specific health concerns or deficiencies and offer a more concentrated dose of carnitine.

Are L-Carnitine Supplements Safe?

L-Carnitine supplements are generally safe when taken in recommended dosages, typically up to 2,000 mg per day for most adults. Side effects, if any, are usually mild, including digestive discomfort or a fishy body odor. Long-term or high-dose use should be under medical supervision, particularly for individuals with existing health conditions or those taking certain medications. Overall, L-Carnitine can be a safe component of a health regimen when used appropriately.

Medication Interactions With L-Carnitine

  • Thyroid Hormones: L-Carnitine may interfere with the thyroid hormone, particularly in patients with hypothyroidism. It can reduce the effectiveness of thyroid hormone replacement therapy.
  • Anticoagulants (Blood Thinners): L-Carnitine might increase the effects of anticoagulant drugs, potentially leading to an increased risk of bleeding.
  • Chemotherapy Drugs: Some evidence suggests that L-Carnitine might affect the efficacy of certain chemotherapy drugs.
  • Valproic Acid (and other Seizure Medications): L-Carnitine is sometimes used to counteract the side effects of valproic acid, a medication used for seizures, but it can also affect how the body processes this drug.
  • Certain HIV Medications: L-Carnitine may interact with some drugs used in the treatment of HIV/AIDS, affecting their efficacy.
  • Diabetes Medications: Since L-Carnitine can affect blood sugar levels, it may interact with diabetes medications, requiring adjustments in dosages.
  • Blood Pressure Medications: L-Carnitine might interact with blood pressure medications, potentially affecting blood pressure control.

Supplement Interactions With L-Carnitine

  • Antioxidants (like Vitamin E and Vitamin C): L-Carnitine may enhance the effectiveness of antioxidants. This combination is often used in supplements targeting overall health and anti-aging.
  • BCAAs (Branched-Chain Amino Acids): When combined with L-Carnitine, BCAAs may support improved muscle recovery and energy metabolism, but they can also affect how L-Carnitine is used by the body.
  • Coenzyme Q10 (CoQ10): Both L-Carnitine and CoQ10 are involved in energy production. Combining them could enhance their effects, but it’s essential to monitor for overstimulation.
  • Choline: Since L-Carnitine and choline are both involved in fat metabolism, combining them may enhance this effect, but it can also increase the production of TMAO (trimethylamine N-oxide), a compound linked to heart disease.
  • Omega-3 Fatty Acids: These can be combined with L-Carnitine for potential synergistic effects on heart health and energy levels, but they should be used cautiously together to avoid excessive blood thinning.
  • Alcar (Acetyl-L-Carnitine): While both are forms of carnitine, combining them isn’t usually necessary and could lead to an excessive intake of carnitine.
  • Caffeine and Stimulant-Based Supplements: Combining these with L-Carnitine might lead to increased energy levels, but can also cause overstimulation or interfere with sleep.
  • Iron Supplements: L-Carnitine may interact with iron, potentially affecting its absorption and efficacy.

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L-Carnitine: For Exercise Performance & Fertility

L-Carnitine 1000 mg Tablet by NOW

L-Carnitine is a non-essential amino acid that helps to maintain overall good health by facilitating the transfer of fatty acid groups into the mitochondrial membrane for cellular energy production.* It naturally occurs in red meat and other animal source foods, but we recommend supplementation to obtain optimal levels of this amino acid. NOW® L-Carnitine is the purest form, clinically tested, and vegetarian (non-animal sourced).

  • Purest Form, Clinically Tested
  • Boosts Cellular Energy*
  • Transports Fatty Acids*

Suggested Use: Take 1 tablet 1 to 2 times daily. Store in a cool, dry place after opening.

Amount Per 1 Tablet Serving

L-Carnitine … 1g (1000mg)** (Carnipure™) (from L-Carnitine Tartrate

Acetyl-L-Carnitine (ALCAR): For Brain and Nerve Health

Acetyl-L-Carnitine 500 mg Capsule or Powder

Carnitine is an amino acid that helps transport fat into the mitochondria where it is converted into ATP (cellular fuel).*

Acetyl-L-Carnitine (ALC) is a modified form or carnitine that can cross the blood-brain barrier, where it helps to manage oxidative damage, supports mitochondrial function and helps to maintain normal neurotransmitter activity.* Clinical studies suggest that Acetyl-L-Carnitine helps to maintain optimal neurological health.*

Propionyl-L-Carnitine: For Cardiovascular Benefits

Optimized Carnitine

Acetyl L-Carnitine HCl … 800mg
Acetyl L-Carnitine Arginate Di-HCl … 300mg
Glycine Propionyl L-Carnitine HCl … 300mg

L-Carnitine L-Tartrate: For Exercise Recovery

L-Carnitine Tartrate by Klaire Labs

This more stable form of L-carnitine is less susceptible in a dry form to the effects of moisture than pure L-carnitine. Supplies 500 mg of elemental L-carnitine per capsule and is free of synthetic D-carnitine. Suggested Use: Take 1 capsule, 1 to 4 times daily with food or as directed by a healthcare professional.

Amount Per 1 Capsule Serving

L-Carnitine … 500mg* (as L-carnitine tartrate)‡

Food First!

Although this article discusses supplements in detail, don’t forget that we are absolutely committed to the “Food First” approach to nutrition. When it comes to your health, the totality of your eating habits far surpasses the impact of individual nutrients or any single supplement you consume. Even though this article doesn’t delve into the broader picture of your overall diet, it’s crucial to keep this element at the forefront of our minds. Your food needs to provide all the vitamins, minerals, fiber, and phytochemicals to nourish your body systems down to the cellular level.

Food choices, rather than supplements, are the most critical factors for a healthy gut microbiome. These trillions of tiny inhabitants in your gut affect your brain waves; they orchestrate your immune system. They possess the power to create molecules that can switch genes on or off and are even capable of synthesizing neurotransmitters. Opting for organic foods and steering clear of plastic packaging (including those labeled BPA-free) is a smart move to limit toxin exposure. The sum of all these parts leads to a powerful conclusion: the ultimate key to your health lies in the quality and balance of the food you consume. Supplements are secondary.

To Sum It Up

The various types of carnitine supplements, including L-Carnitine, Acetyl-L-Carnitine, and Propionyl-L-Carnitine, each offer unique benefits that can meet different health and wellness goals. L-Carnitine is known for carrying fatty acids into the mitochondria to promote energy production. It has potential to aid in fertility, weight management and exercise performance. Acetyl-L-Carnitine stands out for its cognitive and neurological benefits, making it a popular choice for those looking to support brain health. Propionyl-L-Carnitine is particularly noted for its cardiovascular benefits, including improving blood flow and addressing heart-related conditions.

This Article is Not a Substitute for Medical Advice

Dietary supplements are not designed to diagnose, treat, cure, or prevent any disease. The Supplement Sciences website seeks to provide comprehensive access to the most relevant supplement information along with convenient online ordering. We do not provide medical advice and cannot guarantee that every product suggested is completely without risk. Since each person is unique in their health history and medication use, it is important to discuss supplements with your personal physician. Specifically, pregnant women and individuals being treated for cancer or liver or kidney problems must consult their physician about every nutritional supplement they plan to take. People taking medications for the treatment of HIV or with a history of organ transplant must not take supplements without consulting with their physician.

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