test-What’s the Difference Between L-Carnitine and Acetyl L-Carnitine?
Memory and Brain Support
What’s the Difference Between L-Carnitine and Acetyl L-Carnitine?
Amy Sunderman, MS, RD • March 12, 2024

Discover the benefits and differences between L-Carnitine and Acetyl L-Carnitine

When it comes to popular amino acid supplements, L-carnitine and acetyl L-carnitine cause quite a bit of confusion. Given their similar names and the fact that they’re both slightly different forms of the same amino acid, it’s easy to understand the mixup. But don’t worry: we’re here to explain!

The short answer when it comes to the difference between these two is that L-carnitine is popular among exercise enthusiasts or people looking for help with weight management because of its role in helping the body convert fat into energy. Acetyl L-carnitine, also commonly called ALCAR, goes a step further. While acetyl L-carnitine may also help turn fat into energy, it’s also able to cross the blood-brain barrier to support brain energy and function.

The blood-brain barrier is a protective mechanism that blocks pathogens or toxins from passing through the endothelial membrane. Though it is highly selective, often blocking passage of beneficial molecules and compounds, some amino acids, like acetyl-L-carnitine, are able to make it through to deliver its brain health benefits.

What is L-Carnitine?

L-carnitine is an amino acid that can be found in foods like beef, chicken, fish, dairy and other natural sources. L-carnitine dietary gaps are commonly compensated for with L-carnitine supplements.

L-Carnitine Vs Acetyl L-Carnitine Infographic by Swanson Health

So, how does L-carnitine work? Think of an old-timey steam locomotive, which burns coal to create steam. Adding coal fires up the pistons and keeps the train moving down the track. L-carnitine’s role is not dissimilar to the individual in charge of shoveling coal into the locomotive’s furnace, but instead of shoveling coal into a furnace, L-carnitine transports fatty acids to the mitochondria of cells (where energy is produced) to be burned off and used for energy to fuel the body and keep you moving throughout your day.

This explains why many turn to L-carnitine to enhance their weight management and exercise regimens, as it is excellent at promoting the mobilization of fat from storage deposits to be burned as energy as well as boosting body-building workouts.

What is Acetyl L-Carnitine (ALCAR)?

A different version of the same amino acid as L-carnitine, acetyl L-carnitine is commonly utilized to support brain health due to its ability to cross the blood-brain barrier. Hence, acetyl L-carnitine supplements are used to boost brain energy and focus, a healthy mood, memory health and more.1 Acetyl L-carnitine is also sometimes used to promote male reproductive health.

How Does Acetyl L-Carnitine Affect the Brain?

Once it passes through the blood-brain barrier, acetyl L-carnitine helps to promote synthesization of a primary neurotransmitter in the brain known as acetylcholine. Acetylcholine’s primary role is to allow for communication between nerve cells. By boosting acetylcholine synthesization, acetyl L-carnitine plays an essential role in supporting memory health, focus and alertness, improved sleep and muscle contractions.

Should I Take L-Carnitine or Acetyl L-Carnitine?

This depends on your goals. If you’re strictly looking for a supplement to promote enhanced fat burning for your weight maintenance regimen, L-carnitine supplements may be the answer. However, if you’re looking for broader results that include various brain health boosting features, acetyl L-carnitine may be a better choice.

L-Carnitine Dosages for Adults

  • To Support Proper L-Carnitine Levels: Studies suggest that taking 990 mg orally in supplement form, two to three times daily may support proper L-carnitine levels for those who may have lower levels.2
  • L-Carnitine to Promote Heart Health: Research on the effects of L-carnitine for those with heart concerns has focused on taking between 1.5 to 3 grams orally every day for up to 34 months.2
  • L-Carnitine for Kidney Function: For those with kidney health in mind, studies have used a dosage of between 0.64-3 grams daily for three weeks to one year.2

Acetyl L- Carnitine Dosages for Adults

  • Acetyl L-Carnitine for Memory Health: Studies have focused on an oral dosage of between 1,500-2,000 mg of acetyl L-carnitine for a period of three months for memory health.1
  • To Support Male Reproductive Health: To boost testosterone levels in men, research has focused in on two grams of acetyl L-carnitine as well as two grams of propionyl L-carnitine each day for six months.1
  • Acetyl L-Carnitine for Energy: Research has delved into the effectiveness of using acetyl L-carnitine to boost energy as we age, which includes a dosage of two grams twice daily for 180 days.1

As you can see, while L-carnitine and acetyl L-carnitine are closely-related amino acids, they each have their own role to play in helping to boost the health of your body. Hopefully, this will give you a greater insight into which one is right for the specific health goals you’re looking to achieve. Whether you’re looking to burn fat in order to fire up your workouts with an L-carnitine supplement, or leaning towards an acetyl L-carnitine supplement to offer an added brain health boost to the equation, these amino acids will both make a great addition to any health and wellness regimen.

Amy Sunderman, MS, RD, Director of Science & Innovation Registered Dietitan

About Amy Sunderman, MS, RD
Director of Science & Innovation, Registered Dietitian, Swanson Health

Amy is a registered dietitian, nutritionist and author with over 20 years of experience in the supplement industry. Amy is passionate about dietary supplements and the health benefits they offer. She enjoys working to find novel nutritional ingredients with strong clinical research behind them to drive innovation and provide health-promoting products to consumers.

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.


1 Acetyl L-Carnitine. WebMD. Read source

2 L-Carnitine. Center for Internal and Integrative Medicine. Read source