Meldonium vs L-carnitine: what to choose and for whom

The query «meldonium or carnitine» most often comes from people looking for an agent for endurance, weight loss or «heart support». The editorial team explains why for an athlete this comparison ends at the WADA rules, in which situations L-carnitine may make sense, and when the decision about meldonium can be made only by a doctor.

Who asks this question and why

Among those who compare meldonium and L-carnitine, several groups can be distinguished. The first is athletes and amateurs interested in endurance and recovery. The second is people losing weight who hope to «burn fat» more effectively. The third is patients with cardiovascular diseases or their relatives, who have heard about «cardioprotective» properties.

For each group the answer is different. For the first the deciding factor is the anti-doping status. For the second - realistic expectations of weight-loss supplements. For the third - a doctor's decision and evidence-based medicine, not advice in a sports-nutrition shop.

It is also important to understand that these two substances are not interchangeable «versions of one agent». As we explained in the article «Meldonium vs L-carnitine: what is the difference», meldonium lowers the carnitine level, while the L-carnitine supplement replenishes it. That is, they work in opposite directions of one pathway.

So the correct question is not «which of the two is better», but «do I need to affect carnitine metabolism at all, and am I allowed to». The answer to it largely determines the choice too.

For athletes: why meldonium is ruled out

Since 2016 meldonium has been on the WADA Prohibited List as a metabolic modulator and is banned at all times - both in and out of competition. For any athlete who may be tested, the question of choice here is settled by the rules.

The experience of 2016, when dozens of athletes got positive tests, showed another important thing: the substance can be detected for a long time after intake is stopped. So even a «past» course taken as prescribed by a doctor can have consequences. Athletes with medical indications for any banned drug should consider a therapeutic use exemption (TUE) together with their doctor and federation.

Besides the rules, there is a scientific question too. There are no convincing independent studies that would show that meldonium improves athletic performance in healthy people. Its popularity in sport was largely based on theory and on practice, not on randomised studies.

L-carnitine, on the contrary, is permitted. Athletes should only bear in mind the general risks of supplements - possible contamination of the product with banned substances - and choose products with independent doping-free certification. The WADA restrictions on intravenous infusions should also be taken into account.

For whom L-carnitine may be useful

People with confirmed carnitine deficiency.Primary deficiency is a rare genetic disorder of the OCTN2 transporter. Secondary deficiency can develop with haemodialysis and against the background of some drugs. In these cases carnitine is a medicinal product prescribed by a doctor.

People who train and want to improve recovery.According to the review by Fielding and co-authors (2018), L-carnitine tartrate in a number of studies reduced markers of muscle damage and soreness after exercise. The effect is moderate, and it should be considered an addition to proper sleep, nutrition and training planning.

Vegetarians and vegans.Their carnitine level is somewhat lower, because the main dietary sources are meat and dairy products. However, the body is able to synthesise carnitine on its own, and there is usually no overt deficiency in healthy vegetarians. A supplement may be considered but is not mandatory.

People losing weight.Here expectations are often inflated. Meta-analyses show a small effect on body weight, not comparable to the result of a calorie deficit. Carnitine does not «burn fat» on its own: fatty acids are oxidised when the body needs energy.

How to take L-carnitine so that it makes sense

The key to understanding the supplement is the study by Wall and co-authors (2011). Carnitine content in muscle increased only when L-carnitine was taken together with a large portion of carbohydrates that stimulated an insulin release, and only after several months. In the study participants received 2 g of L-carnitine tartrate with 80 g of carbohydrates twice a day for 24 weeks.

In practice this means several things. First, a short course «for a month» is unlikely to change the carnitine content in muscle. Second, taking it on an empty stomach before cardio «to burn fat» has no scientific basis. Third, a daily 160 g of extra carbohydrates is far from suitable for everyone, especially people on a calorie deficit.

In studies on recovery, L-carnitine tartrate was most often used at doses of 1-3 g a day over several weeks. It makes sense to take it with food. The acetyl-L-carnitine form is studied mainly in the context of the nervous system, not athletic performance.

• choose a product with a stated form (tartrate, acetyl, base) and content per serving;
• take it together with food that contains carbohydrates;
• assess the effect after several weeks, not days;
• if there is a «fishy» body odour or digestive upset, reduce the dose or stop taking it.

Meldonium as a medicinal product: its place and limitations

Meldonium is registered in a number of countries, including Ukraine, as a medicinal product, most often for the combined therapy of ischemic heart disease and disorders of cerebral circulation. The decision on its prescription, dose and duration is made by a doctor, taking into account current clinical guidelines, in which meldonium is, as a rule, absent.

It is worth understanding that in international cardiology guidelines (in particular those of the European Society of Cardiology) meldonium is not part of standard treatment regimens. This is due to the lack of large independent randomised studies with hard endpoints, such as mortality or heart attacks.

The editorial team does not support self-administration of meldonium «for energy» or «for the heart» without a diagnosis. Among the possible adverse reactions are allergic manifestations, digestive upset, tachycardia, changes in blood pressure and agitation. In patients with severe liver and kidney diseases the drug is prescribed with caution.

People who already take meldonium as prescribed and at the same time do sport at a level where doping control is possible must inform their doctor and consider a TUE procedure or an alternative. Ignorance of the status of a substance does not release one from responsibility under anti-doping rules.

Editorial conclusions

For an athlete who may be tested, the choice between meldonium and L-carnitine is unambiguous: meldonium is banned, L-carnitine is permitted. For amateurs and those losing weight, L-carnitine may be a moderately useful auxiliary agent provided expectations are realistic and it is taken correctly.

Meldonium is a medicinal product whose place is determined by a doctor. It is not «enhanced carnitine» and is not suitable for self-administration with the aim of improving performance.

For more on the mechanisms of both substances, read the article «Meldonium vs L-carnitine: what is the difference». We also recommend the editorial pieces «Creatine vs Beta-alanine: what to choose and for whom», on the WADA Prohibited List and on the contamination of sports supplements.

References

1. World Anti-Doping Agency. The World Anti-Doping Code International Standard: Prohibited List. Montreal: WADA; оновлюється щорічно.
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3. Dambrova M, Makrecka-Kuka M, Vilskersts R, et al. Pharmacological effects of meldonium: biochemical mechanisms and biomarkers of cardiometabolic activity. Pharmacol Res. 2016;113(Pt B):771–780.
4. Wall BT, Stephens FB, Constantin-Teodosiu D, et al. Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans. J Physiol. 2011;589(Pt 4):963–973.
5. Fielding R, Riede L, Lugo JP, Bellamine A. L-Carnitine supplementation in recovery after exercise. Nutrients. 2018;10(3):349.
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7. Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.