You may or may not have heard about the supplement L-Carnitine which is highly marketed as a weight loss supplement. I thought I’d take on a little investigation to see what I could find out about it.

Well let me tell you this article was not an easy one to research. There are a lot of conflicting studies and the most reputable agree that there is no clear evidence to show that L-Carnitine can help with weight loss.

What is L-Carnitine?

Well L-Carnitine is the biologically active form of the nonessential amino acid know as carnitine. Carnitine is made in the liver and kidneys to transport fatty acids into our muscle cells and provide us with energy.

Can L-Carnitine Help with Weight Loss?

This is the part that is tricky. Although the old school studies showed that L-Carnitine supplementation does not help with fat, carbohydrate, and protein metabolism during moderate intensity exercise, there is some benefit in reducing the metabolic stress of exercise.

In other words, L-Carnitine helped reduce the stress response to exercise and allow muscles to recover more quickly. Some modern research has also indicated that L-Carnitine enhances aerobic power, has anti-oxidant properties and also enhances blood flow to the muscles.

Can We Get Carnitine From Food?

Well other than the pure form in supplements, the foods with the highest concentration of carnitine are red meat (steak and ground beef), pork, cod, and dairy products (cheese, ice cream, milk). Generally our diets will therefore consist of 20 to 200mg/day and our body can only absorb a maximum of 2g at one time.

Interesting Note:

Canada has a strict regulation against importation of L-Carnitine as a supplement into the country. My research indicates that there is no major reason for this other than the fact that no organization has taken the initiative to register L-Carnitine as a natural product with Health Canada.

Are there Side Effects of L-Carnitine Supplementation

I was not able to find any scientific document of L-Carnitine having negative side effects other than possibly affecting people who have underactive thyroids (on the flip side it is currently being researched to help people with overactive thyroids). Some people have indicated that with extremely high doses of 5 or more grams per day caused diarrhea.


The jury is still out on L-Carnitine. It is an interesting supplement as new studies are showing that it can help reduce oxidative stress from exercise which means that it can help with muscle recovery and growth. With more muscle growth that would mean a higher metabolic rate and in turn fat loss if exercise is continued. If you are in the states you may want to try it out and see how it works for you otherwise a wait and see approach is the only option especially to those in Canada.

For those in the US, two of the best sellers of L-Carnitine are:

Have you taken L-Carnitine and found it to be helpful for you? Please leave a comment below: