The instructions for using L-carnitine can be expressed in an absurdly simple and concise way: DO NOT take it.
The basis for such categoricalness is the uselessness of this popular supplement for the goals that are used as the main levers of its sales: weight loss and muscle gain.
For most people, L-carnitine is known as an effective fat burner, and 99% of those who ask the question “how to take L-carnitine?” hope to lose weight with its help.
However, scientific research does NOT confirm its effectiveness for weight loss, muscle gain, and improving other performance indicators in sports.
There is only a narrow circle of individuals for whom carnitine may be recommended for medical reasons.
This category does NOT include either athletes or girls dissatisfied with the fullness of their bellies, cheeks, and thighs.
Sounds not very convincing? Then read on.
Main thoughts:
The best form of carnitine is considered to be acetyl-L-carnitine, and the worst is D-carnitine
Instructions for using L-carnitine
If the prelude to this article seemed unconvincing, it is very important that before taking L-carnitine (for weight loss, muscle gain, or anything else), you listen to the following recommendations:
1 Familiarize yourself with the material What is L-carnitine and what is it for?. This is a fairly detailed scientific review of this supplement, its properties, and side effects. Despite being a natural supplement, it has one quite serious side effect.
2 If you want to understand how to take L-carnitine for weight loss or body drying, then read our material Truth and LIES about the effectiveness of L-carnitine for weight loss. There we show how sellers lie to sell it to you, as well as provide scientific evidence and opinions from authoritative portals about its uselessness.
3 If you are hoping to gain more muscle mass with the help of L-carnitine, then take the time to study the scientific evidence of its INeffectiveness for this in the material How effective is L-carnitine for gaining muscle mass?
4 Come back here, and if the desire to experiment with carnitine hasn’t disappeared, read on.
Recommendations from scientists on who and how to take L-carnitine
First of all, it is important to understand that carnitine is not a supplement recommended for general consumption.
Scientists state that the bodies of healthy children and adults synthesize sufficient amounts of it from the amino acids lysine and methionine to meet daily needs, so there is no need for additional intake 7-9.
This is also true for athletes, whose diets are rich in protein containing the aforementioned two amino acids 10.
The opinion of scientists on the advisability of taking L-carnitine in sports is succinctly expressed in the following statement:
“20 years of research on carnitine do not confirm its effectiveness in increasing muscle strength or mass, endurance, or recovery speed, and there is no scientific justification for its additional use by athletes.“
Scientists believe that there is no need for athletes to take additional L-carnitine, as their diet provides enough protein for its natural synthesis. The exception is vegetarian athletes.
There are several groups of people for whom it may be recommended to take L-carnitine supplements due to a high risk of deficiency:
1 Vegans and vegetarians (especially athletes)
In the diets of vegans and vegetarians, there are no animal products necessary for ensuring the internal synthesis of carnitine. Physical activity increases the load on the heart and muscles. A deficiency of carnitine can lead to the development of side effects.
The level of carnitine in the body is determined by how much is obtained from food (mainly from meat and dairy products), as well as the natural synthesis within the body. In vegetarians and vegans, its level in the body is 2-6 times lower than in omnivores 5,6.
In omnivores, about 75% of all carnitine in the body comes from food 1.
For vegetarians, it would be justified to take L-carnitine in the form of supplements, but studies on the benefits of additional intake for this category are lacking.
Recommended: Vegetarianism/Veganism and Sports: RISKS
2 People with disorders in the synthesis and absorption of carnitine
Failure of the natural production mechanism of carnitine in the body can occur due to:
- genetic disorders,
- certain diseases of the liver, kidneys, brain,
- the intake of certain medications (for example, very commonly – anticonvulsants and the popular sports drug Mildronate).
Some medications can interfere with the absorption of carnitine and lead to its deficiency.
A good example is the heart medication Mildronate, which reduces the level of L-carnitine by 18% after 4 weeks of use, and with long-term use leads to the development of its deficiency 6.
The bodies of premature infants often cannot synthesize L-carnitine, and it is prescribed to them in the form of supplements.
The synthesis of carnitine within the body can also be disrupted in certain rare genetic diseases. In this case, additional intake is also necessary.
Carnitine is used to treat nerve pain due to diabetes or neuropathy, and is also prescribed after undergoing cancer treatment.
In all the cases mentioned, the involvement of a doctor is important.
3 Pregnant women and elderly people
The intake of carnitine in the form of supplements is also recommended for pregnant women, especially after the 12th week (at a dosage of 500 mg per day) 2 and for elderly people over 70 (at a dosage of 2 g per day) 3,4.
Categories of individuals who may be recommended additional intake of L-carnitine: vegetarians and vegans, pregnant women, elderly people, those with impaired internal synthesis of carnitine. Athletes are not included in this list.
Which carnitine is better to take: from natural products or from tablets?
If you belong to one of the risk groups for carnitine deficiency, you have a choice: to take carnitine as a special supplement or to eat more foods that contain it.
Carnitine is a natural substance found in animal products, primarily meat and fish (hence its name “carnus” – flesh). The redder the meat, the more carnitine it contains.
The best natural sources of L-carnitine are:
- beef: 81 mg per 85 grams;
- pork: 24 mg per 85 grams;
- fish: 5 mg per 85 grams;
- chicken: 3 mg per 85 grams;
- milk: 8 mg per 230 ml.
Carnitine from natural foods is absorbed significantly better than from tablets: about 60-80% of carnitine from food is absorbed, while only ~15% from tablets 12.
Additionally, our body can produce carnitine from two amino acids, methionine and lysine. Therefore, if the diet contains enough complete protein, there is no point in taking supplements.
We recommend: What to replace protein with at home? 30 natural protein-rich foods
L-carnitine tablets are only necessary in special cases: for example, if the synthesis within the body is disrupted due to certain diseases.
The advantages of carnitine in supplement form are significantly higher dosages: the carnitine content in them is thousands of times higher than the amount you would get even by eating only meat throughout the day.
On average, an omnivorous person consumes about 1 mg of carnitine per day. In tablets, the amount is 1-4 grams. Adjusting for poorer absorption, we get about 250-500 mg, which is also significantly more than from food alone.
Another question: do you need that much???
As we have already established, it depends on the degree of deficiency, not on the desire to lose weight or gain mass.
If L-carnitine worked as a fat burner, then perhaps loading it in large doses would be beneficial.
Scientists say that when taking L-carnitine in such doses in tablet form, its concentration in the muscles does not increase 11.
Draw your own conclusions.
Carnitine from natural products is absorbed 4-5 times better than from supplements. Good natural sources of carnitine are meat and fish.
How to take L-carnitine: dosage
The standard dose of L-carnitine is 500–2000 mg per day.
However, it should be noted that different forms of L-carnitine have different concentrations of the active substance.
To summarize the available information on dosages used in various studies, we get the following:
- Acetyl-L-Carnitine: This is one of the best forms of L-carnitine for heart and brain health. The dosage ranges from 600 to 2500 mg per day.
- L-Carnitine L-Tartrate: This form is most commonly used in sports due to its high absorption rate. The dosage varies between 1000–4000 mg per day.
- Propionyl-L-Carnitine: This is the best form for improving blood flow in those who suffer from frequent high blood pressure or other cardiovascular issues. The recommended dosage is between 400–1000 mg per day.
The average dosage of 2000 mg for all forms of L-carnitine is considered safe in terms of side effects with long-term use.
Although the concentration of the active substance varies among different forms of L-carnitine, a dosage of 2000 mg per day for all forms is considered safe for use.
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In what form is it better to take carnitine? The best carnitine
There are several forms of carnitine, each used for different purposes and containing different amounts of the active substance:
- Acetyl-L-Carnitine (ALCAR) – penetrates well into the brain and is used in medicine to treat certain neurological diseases, particularly Alzheimer’s disease;
- L-Carnitine L-Tartrate – most commonly used in sports nutrition due to its high absorption rate. It may be beneficial for reducing muscle soreness and speeding up recovery 25.
- Glycine-Propionyl-L-Carnitine – stimulates the production of nitric oxide, known for its properties to improve blood flow 24, and is used in medicine to treat vascular diseases and high blood pressure.
- D-Carnitine – an inactive form that can lead to a deficiency of carnitine in the body as it hinders the absorption of other forms 23.
Different forms of carnitine contain different amounts of the active substance. The equivalent dosages are as follows:
(630-2500 mg of acetyl-carnitine) = (1000-4000 mg of L-carnitine L-tartrate) = (1000-4000 mg of Glycine Propionyl L-carnitine).
Acetyl-L-Carnitine is recognized as the best form of carnitine due to its good absorption and suitability for most purposes.
D-Carnitine is considered the worst type of carnitine, and its use should be avoided.
The best form of carnitine is considered to be acetyl-L-carnitine, while the worst is D-carnitine.
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How to take L-carnitine: recommendations from bodybuilding.com
L-carnitine is best taken with carbohydrates
Bodybuilding.com:
“New studies suggest that to maximize the effect of taking carnitine, it is necessary to ensure a high level of insulin in the blood: this facilitates its entry into muscle cells, where it is actively used. On the other hand, L-carnitine in the muscles enhances the action of insulin, helping to deliver more glucose to muscle cells for energy.“
When is it better to take carnitine: before or after a workout?
There is no scientific evidence for the effectiveness of L-carnitine. Scientists unequivocally state this.
Accordingly, whenever you take it, it is unlikely that the effect will change.
For comparison, here are the recommendations from Bodybuilding.com:
“It is best to take L-carnitine immediately after a workout, but it can also be taken at any other time with carbohydrate or protein-rich food. In combination with other fat burners, it is better to use acetyl-L-carnitine.
Carnitine is best taken with 30-40 grams of carbohydrates and 20-40 grams of protein, preferably during a meal. These recommendations apply to all forms of carnitine: L-carnitine, L-carnitine L-tartrate, or propionyl-L-carnitine.”
Decide for yourself whom to believe.
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How to take L-carnitine for weight loss
Scientists do not recommend doing this due to the lack of conclusive evidence of its benefits for this purpose.
In contrast, sellers have more data.
Bodybuilding.com’s opinion on this matter:
“The most effective strategy for taking L-carnitine for weight loss, according to the author of bodybuilding.com, is as follows: 2-3 doses of acetyl-L-carnitine throughout the day with other fat burners on an empty stomach and 1 dose of L-carnitine L-tartrate with food after a workout.”
We doubt that this recommendation is worth trusting.
How often should you take carnitine?
Bodybuilding.com:
“At this time, there is no scientific basis for the periodicity of carnitine intake. Regular intake will ensure a constant effect.”
Also, regular intake will ensure a constant flow of profit…
Recommended: Is Protein Useful for Weight Loss?
Conclusion
Before seeking an answer to the question “how to take L-carnitine?”, it is more appropriate to try to understand “is it worth your money?”
A very narrow group of people is at risk of carnitine deficiency, excluding athletes.
Carnitine from natural products is absorbed significantly better than that sold in tablets and is sufficient for most people to meet their daily needs.
Carnitine in tablet form may only be recommended for use in special medical cases when the body is unable to synthesize it. But it is not suitable for weight loss or muscle gain.
