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Fat Burner vs L-Carnitine: Which is More Effective?

Isaac Robertson
Published by Isaac Robertson
Fact checked by Donald Christman, BHSc FACT CHECKED
Last updated: September 5, 2022
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The majority of my clients will always ask the question if there are any supplements that we recommend to speed up and boost their fat loss efforts.

Being in the fitness industry for years, it’s generally a question that we answer with products like fat burning and L-carnitine supplements.

But before you just buy the first supplements you can find, let me show you what they do and when people should use them.

What Are L-Carnitine Supplements?

A bottle of L-Cartnitine supplement

L-carnitine supplements usually come in powder or capsule form, and they are designed as a dietary supplementation to support the natural L-carnitine production in your body.

The way it works is as a transporter of fatty acids to the individual cells in your body.

It’s kind of like the FedEx of your body, and any L-carnitine deficiency can reduce the amount of fatty acids available for energy production in the mitochondria of muscle cells and to support brain health.

Some studies have shown that boosts of this amino acid may help your body burn away love handles, making it a suitable weight loss supplement [1].

“L-carnitine is a chemical similar to an amino acid that is produced in the body. The body can convert L-carnitine to other chemicals called acetyl-Lcarnitine and propionyl-Lcarnitine.”


You can increase your L-carnitine intake through animal products like meat and dairy. But to help with weight loss goals, it may work better to get consistent boosts from supplements.

Here are the three most common forms you’ll find on a supplement label:

  • Acetyl L-carnitine
  • Propionyl L-carnitine
  • Carnitine L-tartrate

It’s also important to note that you don’t confuse L-carnitine with CLA (conjugated linoleic acid), which is an entirely different supplement but often mistaken.

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What Are Fat Burners?

A bottle of Fat burner supplement

Fat burners are supplements that combine stimulating and non-stimulating ingredients to support your metabolism and trigger natural burning processes.

In most cases, this involves triggering thermogenesis, which is a process your body uses to slightly raise your core temperature by burning off excess body fat reserves [2].

These supplements often include ingredients like green tea extract, caffeine, forskolin, Yohimbe, and glucomannan, but the formulas can vary a lot in strength.

It’s important to note that these are not designed as a magic weight loss pill.

But they may help to burn off a few grams of body fat a day when combined with a healthy diet and workout routine.

You’ll also find that some fat-burning products contain L-carnitine, allowing you to get an energy boost along with the fat-burning benefits.

Let’s take a closer look.

Fat burners we recommend trying:

3 Main Differences

Supplements close up image

Like I’ve done in other comparison blog posts, I broke this section down into three parts.

1. Benefits

Fat-burning supplements provide a way for folks to:

  • Support natural metabolic processes, and
  • Lose weight.

Performance athletes and bodybuilders also often use them to support the cutting phases of their training plans.

And there is evidence to support their use for mental stamina through stimulants like caffeine, which can have a positive effect on motivation.

The benefits of L-carnitine, on the other hand, include:

  • Increased energy production for your muscles and brain, and
  • Reduced muscle soreness after exercising.

Remember though that it’s not a replacement for a muscle recovery protein shake but rather an extra boost.

The energy release may also help stamina during exercise, which could help build up more muscle mass in the long-term.

2. Side Effects

A woman struggling to sleep

One of the main side effects of fat-burning supplements is that they often function as stimulants on the brain as well.

It’s like having a shot of strong espresso.

This could make you feel jittery and struggle with getting enough refreshing sleep.

That’s why it’s important to get the timing right for these supplements to work at their best.

L-carnitine is generally deemed to be safe for general use by the Food and Drug Administration, and most folks won’t suffer a side effect from a dose up to 2 grams per day.

However, if you have any underlying stomach health conditions or sensitivities, then beware that it may cause some nausea.

3. Suitability And Timing

Because of the limited negative effects of a fat burner and L-carnitine supplement, these are generally suitable for the majority of athletes.

As long as you get your expectations in place and understand that they support a healthy diet and workout routine, then it mainly becomes a question of the best timing.

Our suggestion is to take the recommended dose for your chosen product and then spread it out evenly throughout the day.

That allows you to get more of the benefits to breakdown fat and support your energy levels.

Just avoid taking fat burners too late in the day, as the common stimulants could mess up your sleep.

Choosing For Your Personal Needs

Man lifting a dumb bell

The first thing I would say is that these energy and burner supplements are not suitable all the time. Both men and women have to fix their diet first and then consider how they structure a workout routine.

You should only consider a supplement when that combination is properly in place.

And here’s what you should use to decide.

1. Bodybuilding

The example I’ll use here is a bodybuilder going through a bulking phase where they are on a calorie surplus diet to support the high-intensity weight lifting.

The main goal here is to build up as much muscle as possible in a short space of time. But the increased food intake will also result in a buildup of fat cells.

On the one hand, you could argue that fat-burning supplements might help to control how much your BMI increases.

Personally, my recommendation is to not mix bulking and cutting efforts. However, L-carnitine is a suitable option from a nutrition perspective as it may provide better stamina and less soreness after training.

2. Weight Loss And Cutting

A woman inside an oversized jeans

Once a bodybuilder has bulked up over several weeks, there’s a need to remain in control of body composition.

And that’s where fat burners seem to provide a helping hand.

While you’re going through a calorie deficit as part of your diet, your body will naturally burn fat.

But you don’t want to spend more time in a cutting phase than you have to.

Also Read: Best Nighttime Fat Burners

That’s where a burner supplement comes into play, as even a single percent drop in BSI could make a difference.

3. Daily Work Activities

Our team’s experiences with both of these products have been positive for daily work and life activities.

Not only from a general health benefits perspective, but we have noticed that we feel more energized.

Part of that will come from mental stimulation through ingredients like caffeine, but we’ve had similar results with non-stimulating products.

However, I would suggest that you avoid taking them every day, as you can become used to the effects and not trigger a positive response.

Related Posts:


Does L-carnitine burn belly fat?

Yes, L-carnitine may burn belly fat, but in a limited way. It plays a more critical role in delivering fatty acids for use in cell mitochondria. That means an increased supply could reduce the risk of a bottleneck for flabby stuff being burned away.

Can You Take L-Carnitine on an Empty Stomach?

Yes, you can take L-carnitine on an empty stomach, and nutritionists often recommend it.

The reason is that your body will absorb and process the amino acids a lot quicker. Just keep an eye on symptoms of nausea which are rare in both men and women.

Which One Will You Pick: Fat Burner or L-Carnitine?

While I always tell clients to stay far away from any supplements that promise to give you a slim body while sitting on the couch with a box of donuts, L-Carnitine supplements can support a good exercise routine.

Our experience and research into the health benefits are supported by nutritionists and dietitians that we work with.

Try out these weight management supplements, and then report back to us how well they worked out.


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