L-carnitine (Pt. 1)

03 Jul 2017 no comments HAB Extract Categories General Suppliments

We have seen how good circulation is essential to deliver the nutrients our cells need to produce energy. The heart in particular is so metabolically active that it requires a constant supply of energy to pump 60 to 100 times a minute everyday for years. By improving circulation, the ‘Heart and Body Extract’ ensures that the nutrients in the food we consume reach the cell where they can be turned into energy the heart can use. In the words of Dr. Stephen Sinatra, “Our heart muscle is one of the most responsive organs in the body for targeted nutritional supplementation” (1).

In this blog, we will look at a nutrient that is essential to make this conversion from food to energy. We are talking about L-carnitine, a vitamin like nutrient that, while it doesn’t have a direct effect on blood flow, it can help maximize cellular energy production. Together, the ‘Heart and Body Extract’ and L-carnitine can be considered a powerful combination that can benefit our heart health greatly, as we will see. First, we will look at how the body converts our food into energy. Then, we will discuss the different conditions in which L-carnitine has been found to be helpful.

How does the cell convert nutrients into energy?

When it comes to heart health, energy metabolism is critical. Both the food we consume and oxygen are essential for the production of energy. Our food choices should be have this principle in mind. After all, we do not eat only for the sake of pleasure, but to provide the building blocks our body needs to thrive. It is important then to understand how the body converts food and oxygen into energy.

Energy metabolism occurs via three metabolic pathways:

  1. The glycolytic pathway
  2. The krebs cycle
  3. The Electron transport chain of oxidative phosphorylation

All of these are extremely important for cellular health. In the glycolytic pathway, glucose, a simple sugar made by the body from carbohydrates, becomes the body’s main source of energy. However,

glucose only provides short bursts of energy and cannot keep the cell working for long periods of time. Only three molecules of ATP are formed this way. What is more, under conditions of oxygen deprivation, like is the case of ischemic heart disease, the energy that is produced from glucose turns into lactic acid quickly, increasing acid levels in the cell. This can cause cellular stress and a burning sensation in heart muscles like is the case of angina. This form of energy, though important, is not the preferred source of energy for the heart.

Via the other two metabolic pathways, the body can obtain great amounts of energy from fatty acids. When oxygen is present, fatty acids become the preferred energy fuel, producing an astounding 129 molecules of ATP. The burning of fats contributes to 60-70% the heart’s energy. And this is when L-carnitine comes into play, because L-carnitine is the only nutrient that can transport fatty acids across the inner membrane of the mitochondria to begin a process called ‘beta-oxidation’. Without it the body could not metabolize fats, and the heart would suffer for lack of energy.

It is in the krebs cycle that fatty acid metabolism occurs. First, electrons from fatty acids are removed, the electrons then travel through the electron transport chain and make ATP. The energy taken from the electrons is used to attach inorganic phosphate to ATP in order to reform it; oxygen is required for this pathway to function. Co-enzyme A also helps to move energy substrates into the mitochondria by binding to fatty acids and other molecules, thus helping them be transported across lipid membranes.

The importance of oxygen is vital, without it, like is the case of ischemia (lack of oxygenated blood flow to the tissue), or hypoxia (oxygen deprivation to the cell) the recycling of energy slows down and this causes ATP to be used faster than it can be replaced.

What is L-carnitine?

L-carnitine is a vitamin-like nutrient, which means that it can be obtained through diet and it is made by the body too. The word ‘carnitine’ comes from the latin word ‘carnis’ which means ‘meat’. L-Carnitine, therefore, is mainly found in protein. The highest sources are mutton, lamb, beef, other red meat and pork in that order. The quantities in plants are rather low, 90% lower than in meat, so vegetarians may show a higher deficiency of this nutrient. Plants also are low in the other nutrients that are needed to metabolize L-carnitine, methionine and lysine. It is important then for vegetarians to supplement with these nutrients. It is also significant that its production slows down with age, so it is important to obtain it through supplementation as we age.

Biosynthesis of L-carnitine

L-carnitine is derived from two amino acids, lysine and methionine. The body synthesizes these via a series of metabolic reactions involving these two amino acids together with niacin, vitamin B 6, vitamin C and iron.

To make L-carnitine, the body goes through different steps and needs the following nutrients to synthesize it: the amino acids L-methionine and L-lysine , vitamin C, B 6, niacin, and iron. Without these nutrients L-carnitine will not be synthesized properly, thereby the importance of obtaining these from the diet. Apart from this, L-carnitine is produced in the kidneys and liver.

Functions of L-carnitine

Generally speaking, L-carnitine helps maximize efficient metabolic activity by mobilizing ATP and promoting better use of oxygen. The main function of L-carnitine is to facilitate the transport of long-chain fatty acids across the inner mitochondrial membrane to begin the process called ‘beta-oxidation’. Most importantly, L-carnitine is the only carrier that can do this, so its presence in the cell is an absolute requirement for heart health. Energy recycling, like the one we explained in the manufacturing of ATP, is dependent directly on the amount of L-carnitine available in the cell accelerating energy metabolism.

Another function of L-carnitine is the removal of ammonia, and lactic acid from our tissues which have shown to have negative effects in the brain and heart. For this reason L-carnitine is recommended after strenuous exercise. Exercise can lead to high levels of lactic acid in the body, and L-carnitine can help the body clear high levels of lactic acid from tissues and blood.

L-carnitine is also an antioxidant and free radical scavenger and has the ability to chelate iron.


L-carnitine is the most available and least expensive of all forms. However, because the free form of L-carnitine is very unstable, it makes it not suitable for tablets or capsules. This has led to research to find ways to make it more stable. Several forms have been synthesized: fumarate, tartrate, citrate, lactate and amino carnitines (new molecules with specific amino acids attached to L-carnitine molecules). Between the fumarate and the tartrate versions, the former appears to be absorbed better than the latter. L-carnitine fumarate has a 58% content of L-carnitine and 42% of fumaric. Both of these compounds are naturally occurring substances in living organisms.

A newer version of the L-carnitine is the amino-carnitines, they are the result of bonding certain amino-acids like glycine, arginine, lysine, and taurine with L-carnitine derivatives. These combinations have been found to increase L-carnitine’s metabolic performance. The resulting molecule is being called amino-carnitine. Combining L-carnitine with these amino-acids provides an interesting synergistic effect on how much of each nutrient is made available, making both more readily used by the body.

Two of these amino-carnitines are acetyl-L-carnitine arginate and acetyl-L-carnitine taurinate. These amino-carnitine combinations are effective because, in general terms, when our bodies are low on L-carnitine they are also low on its amino-acid precursors. Since these precursors are also essential they must be obtained from the diet. In addition, they help us synthesize L-carnitine.

Another reason why these new forms of L-carnitine are so effective is that they have similar properties, therefore they can get better results when bonded together. Arginine taken with L-carnitine aids in the delivery of L-carnitine to ischemic regions of the heart and muscles. The amino-carnitines also work together with D-ribose. The combinations enhance each of the nutrients properties and assist in energy recycling in heart cells. This makes them suitable for heart disease, peripheral vascular disease, diabetes, fibromyalgia and chronic fatigue. For athletes it can also be beneficial because they increase exercise capacity by reducing muscle fatigue, increasing recovery and overall energy.

A specific form of L-carnitine known as propionyl-L-carnitine (PLC) is an L-carnitine derivative that along with the base L-carnitine and acetyl-L-carnitine forms a component of the body’s L-carnitine pool. A dietary version of this PLC is called Glycine-Propionyl-L-Carnitine (or GlycoCarn). It has been shown to be a powerful vasodilator, improving the blood supply to the heart, muscles and other tissues. In some studies it was shown that this form of L-carnitine is rapidly taken up by heart, muscle, kidney and other tissue and what is not needed is secreted through urine.

In a study done with 42 subjects, results showed that supplementation with GPLC helped muscles retain L-carnitine during and after physical activity, as well as the levels of nitric oxide (a powerful vasodilator).


Dr. Sinatra recommends 3,000 mg of GPLC a day, or 500-1000 mg capsules three times a day, between meals. This dosage of GPLC showed to reduce oxidative damage (free radical stress) and triglyceride levels, while increasing nitric oxide levels.

Why carnitine deficiency?

Although L-carnitine is found throughout the diet and is synthesized by the body, it is very common to find deficiencies in this very important nutrient. Deficiencies can be caused by genetic defects, poor diet, co-factor deficiencies of vitamin B 6, folic acid, iron, niacin and vitamin C, liver or kidney disease, and use of some drugs, especially the anti-convulsants.

People with deficiencies can have symptoms like muscle fatigue, muscle cramps, and muscle pain following exercise, also, muscle disease, or cardio-myopathy. This can be seen under the microscope in the presence of fat deposition and abnormal mitochondria in the cells because that is where L-carnitine has its greatest efficacy. Renal failure is also associated with deficiencies, severe malnutrition, and liver cirrhosis and of course, heart disease. Dr. Sinatra believes L-carnitine offers its most greatest use for the heart.

Concluding, “L-carnitine is a heart and muscle specific supplement that must be considered if you have any cardiac or vascular conditions” (1). Together with its derivative, propionyl-L-carnitine , L-carnitine is a key nutrient for the heart. These co-factors not only enhance free fatty acid metabolism but also reduce the intra-cellular buildup of toxic metabolites, particularly where the heart muscle is not getting enough oxygen.

In what follows, we will look at how L-carnitine can improve different heart conditions that have to do with energy metabolism malfunctions.


(1) Sinatra, Stephen T. The Sinatra Solution: Metabolic Cardiology. Laguna Beach, CA: Basic Health, 2011. 101-143. Print.