L-Carnitine Benefits: Does It Work For Weight Loss? (Overview, Results, and Side Effects)

Are you looking to achieve your weight loss goals? Is L-Carnitine the answer? We uncover the truth.

Are you struggling to achieve your weight loss goals? Maybe you are looking for that miracle fat loss ingredient that can help you reach your perfect weight? If so, then you may be interested to hear more about L-Carnitine.

L-Carnitine is most commonly known for its ability to boost your training efforts and physique, helping those who use it to achieve bigger muscle pumps and increased endurance levels in the gym.

What is less known is that Acetyl-L-carnitine can also burn fat through fatty acid oxidation.
In the following article, we will look more closely at this essential ingredient.

Not only to see what benefits it offers and how it can help you lose weight but also to know whether it is safe to use or not.

If you are looking for that little extra helping hand to achieve your dream body, we suggest that you continue reading.


What Is L-Carnitine?

Originally described as a vitamin and now often referred to as an amino acid, the truth is that it is neither.

L-Carnitine or Levocarnitine are instead naturally occurring amino acids structure found in nearly all of the body’s cells. It plays a crucial role in energy production.

L-Carnitine is produced naturally within the human body.

Unfortunately, those who eat a plant-based diet or suffer from genetic conditions may find themselves deficient in this compound. They may require additional supplementation.

Different Types of Carnitine

While L-Carnitine is the most common form, there are other forms available that can be found in your body, the foods you eat, and in various supplements.

These include:


D-carnitine is an inactive form that may cause a carnitine deficiency as it has been shown to inhibit the absorption of other more essential varieties.


Acetyl-L-carnitine is often called ALCAR, and it is the most effective variety for promoting good brain health.

Research has found that Acetyl-L-carnitine may benefit people with neurodegenerative diseases like Alzheimer’s and Parkinson’s disease (1).


Propionyl-L-carnitine is a particular variant that may help with circulatory problems like peripheral vascular disease and high blood pressure.

Increasing your intake of this variant has been shown to cause an increase in trimethylamine n oxide production that can help improve blood flow (2).

L-carnitine L-tartrate

L-carnitine L-tartrate is the variant most commonly found in sports supplements.

It has a rapid absorption rate and may help with recovery and reduce muscle soreness post-exercise (3).

What Does L-Carnitine Do To Your Body?

Around 98% of L-Carnitine is stored in your muscles, although a trace can be found in your liver and blood (4). The primary role of L-Carnitine is energy production.

Fatty acids are transported into your mitochondria and converted into ATP that is burned as energy. Your skeletal and cardiac muscles then use this energy.

During this process, Toxic compounds are removed, which will help prevent the accumulation of these toxins.

Lactic acid is one of the removed byproducts, which means that you won’t experience that painful burning sensation when you workout.

How Does L-Carnitine Help You Lose Weight?

Acetyl-L-carnitine influences lipid metabolism, which means that it can burn fatty acids for energy.

Fat is burnt during this process. This will offer numerous exercise and additional workout performance benefits, such as preventing muscle failure, fatigue, and sluggishness.

With this in mind, you would think that it would make sense that L-Carnitine supplements could help you lose fat? Unfortunately, research has found that this may not always be the case.

In one study of 38 women over eight weeks, L-Carnitine supplementation alongside regular exercise resulted in no discernible reduction in weight (5). During this study, those who took the supplements also experienced side effects such as nausea and diarrhea.

Another four-week study looking at the fat-burning effects of taking L-Carnitine was also disappointing. Those who took the supplement alongside a 90-minute stationary bike workout did not see an increase in fat burned (6).

However, there have been some promising results seen during scientific studies. Another analysis of nine separate studies concludes that when older adults or obese patients take L-Carnitine, they could lose an average of 2.9 pounds (1.3 kg). This was more than those given a placebo (7).

If you want to experience similar weight loss results, then it is recommended that you aim to consume at least 2 grams per day.

What Are The Health Benefits Of Taking L-Carnitine?

Along with its proven ability to produce energy from fatty acids, L-Carnitine supplementation also has the following health benefits:

Heart Health

Adequate energy production is essential for normal heart function, which is what L-Carnitine excels at.

Scientific studies have found that Acetyl-L-carnitine supplements could help reduce blood flow pressure and the inflammation that can lead to cardiovascular disease (8).

One study found that 2 grams of this powerful compound could cause a 10-point drop in systolic blood pressure (9). It indicates a long-term improvement in overall heart health.

Another study found that taking L-Carnitine supplements reduced the number of heart failures and deaths (10).

Brain Function

Research indicates that one form of Acetyl-L-Carnitine’ could benefit mental function.

Animal studies have found that this particular compound could help prevent age-related mental decline (by preventing brain cells’ death) and may improve learning markers (11).

Research on humans has shown promising results, with research showing a reverse brain function decline associated with Alzheimer’s and other brain diseases (12).

Improve Exercise Performance

Although the evidence is mixed, there is plenty of scientific research showing how L-Carnitine supplements can improve exercise and sports performance long term.

It is achieved by improving mitochondrial function and increasing cellular energy.

What is clear from the research available is that higher dosages or those given over a longer-term have resulted in the most significant fat-burning effects experienced.

L-Carnitine’s effects on offer may take a while to appear. Some users only experienced the benefits after supplementing for many weeks or even months. Supplements that contain caffeine or creatine are different as the advantages are quickly experienced.

Regardless, the supposed exercise performance-enhancing benefits of l-carnitine include:

  1. Improved muscle recovery after exercise by increasing circulation and nutrient-rich blood flow, and less muscle soreness (DOMS) post-exercise (13, 14).
  2. An increase in oxygen supply to your muscles (15).
  3. More stamina, because of the increase in nitric oxide production, will increase blood levels and flow around your body. It also helps delay discomfort and reduces fatigue (16).
  4. Increased red blood cell production will increase oxygen and other nutrients transported around your body (17).

There are claims that L-Carnitine supplementation can aid your workout performance by helping to improve both cognition and better brain function.

It will help as it will help keep you focused while working out.

Type 2 Diabetes

Those who have lower L-Carnitine levels have a greater risk of encountering diabetes (18). Therefore it makes sense to supplement with this compound to increase the levels found in your body.

Research has found that using L-Carnitine supplements may be beneficial for those who have type 2 diabetes.

Not only can this compound reduce the symptoms and associated risk factors, but it can also help combat diabetes by improving your body’s ability to use carbs (19, 20).

This is due to the increased production of an enzyme known as AMPK, otherwise known as Activated Protein Kinase.

When Is The Best Time To Take L-Carnitine Supplement?

Most healthy adults won’t need to consume additional Carnitine from their diet or through supplements. It is because your liver and kidneys produce sufficient amounts of lysine and methionine, both of which are amino acids.

While it is possible to increase your intake by consuming animal products, it is thought to experience even more significant benefits of l-carnitine; you may want to consider supplementing it to experience even greater profits. It is essential if you are looking at using it to burn fat.

What Types of L-Carnitine Supplements Are Available?

There are various types of L-Carnitine supplements, including pills, powders, and liquids. Capsules and liquids are the better options because the body quickly absorbs them. Taking them on an empty stomach will also increase absorbability.

You should consume between 30-40 grams of carbohydrates when supplementing with L-Carnitine to experience the best results.

For L-Carnitine to work effectively, your insulin levels need to be elevated. Another l-carnitine’s benefit is that more glucose will be delivered to your muscle cells when your insulin levels are raised. This will help boost energy and your workout performance.

L-Carnitine can also be stacked with caffeine and taken as a pre-workout. It is stimulant-free, so that it can be taken with coffee or green tea without any issues.

How Much L-Carnitine Should I Take For Weight Loss?

The recommended dosage is between 2 grams to 4 grams per day. It would be best if you also split the doses evenly.

The best time to take it is in the morning and before working out.

For How Long Can You Supplement L-Carnitine?

In one study, patients were given a 3-gram dose of L-Carnitine every day for 21 days without experiencing any issues (21).

L-Carnitine has been used daily for patients with severe kidney disease for 52 weeks without problems.

What Are The Side Effects Of L-Carnitine?

If you stick to the recommended dosage, then L-Carnitine is safe for the majority of people. However, some will experience digestive problems. These problems may include:

  • Stomach cramps
  • Nausea
  • Vomiting
  • Diarrhea

There are also reports that L-Carnitine supplements can cause the user to experience a “fishy” odor in their urine, breath, and sweat.

Studies have found that consuming too much L-Carnitine may lead to an increased risk of encountering long-term cardiovascular problems, such as atherosclerosis, which is a build-up of plaque on your artery walls (22).

To avoid these potential problems, you should prevent dosages over 3 grams per day.

It is unclear whether it is safe to supplement with L-Carnitine while pregnant or breastfeeding.

When taking a new supplement, always seek advice from a health care professional, especially if you are considering supplementation every day.


It is worth noting that despite the promising results of numerous studies, research is needed to ascertain whether L-Carnitine supplementation is an effective way of reaching your diet goals.

At present, research is mixed regarding the benefits offered by this amino acid derivative.

Supplement manufacturers will claim that L-Carnitine in supplement form will offer numerous benefits. Just remember that these companies have a business interest and are looking to profit from their supplements.

Unfortunately, while there are benefits of L-Carnitine to be experienced, for example, a more significant number of red blood cells produced, improved brain function, and lower blood sugar levels. You need to look out for a few side effects, significantly if you exceed 3 grams per day.

For older adults or athletes looking for a supplement to help with sports performance, then L-Carnitine could be a solid option, especially if you have low L-Carnitine levels.


Does L-Carnitine affect sleep?

L-Carnitine will not affect your sleep. Supplementing with L-Carnitine has been shown to reduce inflammation and potentially improve both the quality and length of sleep (23).

Does L-Carnitine raise blood pressure?

L-Carnitine will not raise blood pressure, with the opposite shown in most cases.

Supplementing with L-Carnitine has been shown to metabolize blood lipids, reducing insulin resistance and blood pressure (24).

Can I take L-Carnitine on an empty stomach?

Research indicates that you take L-Carnitine on an empty stomach as it is more easily absorbed (25).

Does L-Carnitine suppress appetite?

L-Carnitine is not known as an appetite suppressant; it is better known as a fat burner and performance enhancer.

What foods contain L-Carnitine?

Animal products are some of the best sources of L-Carnitine. Generally speaking, the redder the meat, the higher its carnitine content.

The following foods are the best L-Carnitine sources: Beef, Pork, Fish, Chicken, and Milk.