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L-Carnitine Review - Does This Amino Acid Work? Are lack of effects and no weight-loss deal breakers?

By Summer Banks on Sep 15, 2016
L-Carnitine Review

In the diet industry, don’t mistake marketing for effectiveness. We wanted to know if that was the case with L-Carnitine, so we dug deep into all the details, the ingredient and clinical research. Then, we read tons of reviews and testimonials. Finally, we condensed it to give you the bottom line.


What is L-Carnitine?

To start off with, L-Carnitine is an amino acid. It works to support energy production, heart health and brain function. It is most commonly used to treat patients with a disorder that causes low levels in the body. Depending on the reason for taking it, the dosage instructions will differ.

There’s no specific company behind the amino acid, but there are plenty of well-known ones who sells it. You can buy from just about every vitamin store and online shop. We like that there are proven uses for L-Carnitine and some people actually noticed weight-loss, but read on…

Effective – “Not for All”

First off, L-Carnitine is not effective in all cases, especially when it comes to increased energy, but some people did report improved mental clarity.

“Doesn’t seem to have much effect. Stopped taking after half bottle,” was one experience.

Another shared, “This didn’t do it for me. I didn’t feel a boost in anything. It was pretty much like taking a sugar pill.”

On the flip side:

One person said, “If I don’t get enough sleep they just don’t keep me awake, but on a normal day they help keep me focused and productive.”

“I find this product is helping to reduce my lipid levels and I do experience improved mental clarity,” claimed another.

Weight-Loss – “Not a Big Result”

We also found more than a few reports that weight-loss just wasn’t something many users achieved.

“I didn’t lose any weight or notice any sort of increased performance,” reports a user.

One who tried L-Carnitine said, “I don’t feel energetic, and I haven’t lost any weight, even though I work out.”

Despite the negative claims, there are those who did see results.

One dieter offered, “Always looking for a natural alternative for a weight loss and energy and this seems to be a great one!”

We also found one that claimed, “I have lost weight, however, I am eating a sensible diet, exercising regularly.”

The Science – “Validated?”

There’s plenty of science behind L-Carnitine for the treatment of low levels and even kidney health, but there’s little to no reason to think it will help you lose weight. We assume some companies focus on the function in energy production, but that’s not enough to have a strong effect on your success. Here at DietSpotlight, we want to see the research before suggesting any product.

The Bottom Line – Does L-Carnitine Work?

Have we decided to try out L-Carnitine? Well, we like that there are some proven uses for the amino acid and there are users who noticed weight-loss, but we are hesitant to give the green light because the science just isn’t there. Plus, the number of people who lost nothing is a red flag.

If you’ve got weight-loss on the mind, you may want switch out L-Carnitine with a scientifically tested supplement that works on metabolism. There’s a chance you could take the two together.

Among the best products we’ve seen in 2016 is one called Leptigen. Unlike L-Carnitine, there is a direct connection between the clinically tested ingredients and weight-loss. Customer reviews are absolutely amazing and users, from all over the world, are reporting few, if any, side effects.

Also, it’s a big plus that Leptigen is offered as part of a Special Trial Offer, because the company is confident in the ingredients.

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About the Author:

Summer Banks is an ISSA-Certified Fitness Nutrition Specialist and has reviewed over 2000 diet products. She has years of nursing training, experience as a manager responsible for 15 supplement brands, and completed coursework on Food and Nutrition from Stanford University. full bio.

How Does L-Carnitine Compare?

Previous L-Carnitine Review (Updated December 27, 2012):

What You Should Know

L-Carnitine was discovered in 1905 and is biosynthesized by the amino acids Lysine and Methionine. It transports fatty acids into the mitochondria. In animals it is primarily biosynthesized in the liver and the kidney. It is said to increase energy in the body and said by some to be able to help with weight loss. L-Carnitine is sold as a stand alone supplement and is also an ingredient in a number of weight loss products on the market.


L-Carnitine is biosynthesized by the amino acids Lysine and Methionine.

Product Features

L- Carnitine can be purchased as a stand alone supplement directly from on line stores or in person from drug stores. It is also found as an ingredient in a number of weight loss supplements. It is found in red meat and in dairy products. Some clinical tests have shown that it can have a stabilizing effect on diabetes. This means that if you have gained weight as a result of diabetes and L- Carnitine helps to stabilize your diabetes a pleasant after effect of this may be some weight loss. However anyone with diabetes should never take a stand alone dietary supplement or a weight loss supplement without first seeking the advice of their family physician or diabetes health care professional.

Some athletes take L-Carnitine supplements due to its supposed ability to help increase the energy in the body. However the claims of those manufactures that include L- Carnitine in their weight loss products are more tenuous. Although a couple of very small scale clinical tests have shown than L-Carnitine can lead to weight loss, larger controlled clinical tests are needed to establish these claims as reliable. There is certainly no evidence that L- Carnitine as an ingredient is any more effective than other popular ingredients in weight loss products such as Green Tea Extract.

See Our Featured


  • L-Carnitine is available as a stand lone supplement or as an ingredient in weight loss products.
  • L-Carnitine supplements can be purchased directly on line.
  • L- Carnitine is said to be rich in antioxidants.


  • There is no evidence that L- Carnitine as an ingredient in weight loss supplements is more effective than other ingredients.
  • There has not been enough large scale clinical trials undertaken to back up the claims made for L-Carnitine by some manufacturers of weight loss products.
  • L-Carnitine is found in red meat and dairy products, you do not necessarily need to buy supplements.
  • There is no evidence that L-Carnitine as a stand alone supplement procures superior results in achieving weight loss than other stand alone supplements available for sale.


There simply is not enough reliable evidence available to back up the claims made by some weight loss manufacturers that L-Carnitine helps procure weight loss. We cannot therefore recommend it over and above other weight loss ingredients available.

9 User Reviews About L-Carnitine

Leave comments below
  • 1
    Kasha Mentzer

    My brother suggested I might like this blog. He was once totally right. This submit truly made my day. You cann’t imagine just how a lot time I had spent for this information! Thank you!|


  • 2

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  • 3
    aurelian burton

    what does this product have to do with the kidneys? I think I was told that my level was too high.



    you may eat to much meat and dairy products, it may be difficult to filter, especialy if it is not organic


  • 4

    is it safe to used when brestfeed?


  • 5

    can you please tell me what the benefits of l-carnitine in diabetec children ?


  • 6

    sold in market under what name
    the drug L-CARNITINE?


  • 7
    Darlene Gill

    Can you please tell me the recommened amount of L-Canitine
    that should be taken for me? I am sixty years of age and weigh 150 pounds. How much daily, Please?


  • 8
    brad smith

    is this supplement good for bodybuilders to take for improvement in muscle growth & energy.


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