Acute L-Carnitine Tartrate Supplementation Boosts VO2-Max, Fat Oxidation & Endurance in Elite Wrestlers

The VO2-max boosting effects of l-carnitine tartrate can be beneficial for almost every athlete.

After being the hype supplement in the 1990s, carnitine eventually sank into obscurity; and while the revelation that l-carnitine tartrate may increase the androgen receptor density is the main reason it can still be found in various T-boosters and pre-workout supplements, people appear to have forgotten that the original idea of carnitine supplementation was to increase the effectivity of the carnitine shuttle and thus to increase the oxidation of fatty acids.

As a recent study from the Shahid Chamran University in Iran shows, this could be a mistake. After all, Mostafa Dehghani and his colleagues were able to show that "supplementation of L-carnitine improved effectively the performance by increasing in [sic!] lipid metabolism" (Dehgani. 2015).

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But how did the researchers come to this conclusion and are the results relevant for you and me? Well, the first good news is that we are talking about a randomized controlled clinical human study, in which the subjects were not training noobs, but elite wrestlers.

The twenty healthy elite male wrestlers with a mean age of 22.05 ± 2.6 years, mean weight of 77.10 ± 11.65 kg, mean height of 1.79 ± 0.06 m, and mean body mass index of 23.79 ± 2.45 kg/m2 who participated in this single-blind clinical trial were randomly divided into two groups including test and placebo.

• The test group received 3 g of L-carnitine tartrate in 200 ml water and 6 drops of lemon juice.
• The placebo group consumed only 200 ml water and 6 drops of lemon juice.

Both, the active and placebo treatments were administered 90 minutes before performing the so-called Conconi Test for anaerobic and aerobic threshold, a test of lactate threshold using only heart rate (learn more). Blood samples were collected from brachial veins 90 minutes before the activity, immediately after the activity, and 30 minutes after rest and their serum lipids were measured. The results were analyzed using SPSS-16.

Figure 1: The carnitine supplement led to significant increases in VO2 max (fatty acid oxidation) and the maximal distance the subjects were able to cover in the Concoi test (Dehgani. 2015).

Speaking of results: As the previously quoted conclusion already gave away, 3g of l-carnitine tartrate lead to significant improvements in distance run performance. An effect that was probably at least partly mediated by a significant elevations of the the lipid metabolism and VO2 max.

Immediately after the workout there were transient changes in blood lipids that are surprising, but probably not (health-)relevant (Dehgani. 2015).

Overall, the study at hand does therefore appear to confirm the usefulness of l-carnitine tartrate supplementation in athletes. In that, it's very important that the subjects were highly trained wrestlers and not regular couch potatoes, because the former exhibit training-related improvements in the efficacy of the carnitine shuttle, anyway.

What remains to be seen, though, is whether the effects will still be visible after weeks of supplementation. You, as a SuppVersity reader, should know that acute supplement studies can be deceiving. Therefore, it would be great if we had a 6-week study that compared the performance increases in response to standardized training regimens with and without carnitine supplementation | Comment on Facebook!

References:

• Dehghani, Mostafa, et al. "Effects of L-Carnitine L-Tartrate Acute Consumption on Lipid Metabolism, Maximum oxygen consumption (VO2 max), and distance run Following Aerobic Exhaustive Exercise on Treadmill in Elite Athletes wrestling." The AYER 2 (2015): 189-105.

Carnitine Deficiency of Vegetarians Can Be Compensated W/ 2g of L-Carnitine Tartrate Per Day - Unfortunately, Without Measurable Metabolic or Performance Benefits

Vegetarian athletes do lack carnitine in their diets and muscle, but whether this has significant effects on their performance appears to be questionable based on the results of the study at hand.

In a recent study, researchers from the University Hospital Basel investigated whether the previously observed low carnitine levels of vegetarians could be compensated for by longterm oral treatment with 2g of l-carnitine to replenish the body carnitine pool. Furthermore, the scientists wanted to know whether this would have significant effects on (a) fuel metabolism and (b) physical performance of vegetarians and omnivores.

Novakova et al. hypothesized that "treatment with carnitine would increase plasma and possibly also skeletal muscle carnitine concentrations in vegetarians and would thereby improve skeletal muscle energy metabolism and physical performance" (Novakova. 2015).

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As you already know from the headline of this article, the latter was not the case and that despite the fact that the data in Figure 1 indicates that the daily provision of 2x1g l-carnitine tartrate after breakfast and dinner, respectively, for twelve weeks lead to a significant increase of the muscular carnitine levels of the 16 vegetarian, 18-40 year-old subjects of the study at hand.

Figure 1: Study design (left) and total skeletal muscle carnitine levels according to biopsy (right | Novakova. 2015)

In the 8 omnivore subjects that served as a control, the non-choline supported (choline maximizes carnitine retention | learn more) provision of a total 2g of l-carnitine tartrate did not show a consistent effect on the total carnitine muscle content (Figure 1).

Hold on, wasn't carnitine the stuff that's responsible for the artherogenic effects of meat? If you believe in the headlines in all the major news outlets after the publication of the 2013 study by Koeth et al., the answer would be: "Yes! It does.". If you take a look at the existing scientific evidence it is yet a bit strange that this hold only for processed, best fried, yet not for other types of meat (learn more). One of the latest meta-analyses of in vivo studies indicates by the way that "L-carnitine is associated with a 27% reduction in all-cause mortality, a 65% reduction in VAs [ventricular arrhythmias], and a 40% reduction in anginal symptoms in patients experiencing an acute myocardial infarction." Furthermore, the authors from the Mayo Clinic demand that "study with large randomized controlled trials of this inexpensive and safe therapy in the modern era is warranted" (DiNicolantonio. 2013). And if you look at the epidemiological evidence, it will strike you as odd that eating unprocessed red meat regularly is not associated with a significant increase of heart disease, although it is the type of meat that is highest in carnitine (Micha. 2010).

This observation in the omnivore control group is quite disappointing - specifically in view of the fact that 90% of the people who buy carnitine supplements probably eat meat.

Figure 2: None of the metabolically or performance relevant parameters changed sign. (Novakova. 2015).

In that, it's probably a small comfort that the increase in muscle carnitine levels didn't pay off in terms of increased physical performance, anyway. A brief glimpse at the data in Figure 2 goes to show you: Neither of the tested metabolic and performance variables changes significantly from baseline to post-supplementation. If anything there as a minimal glycogen sparing effect which didn't reach statistical significance either (not shown in Figure 2). Most importantly, however, the VO2max and the RER of which you would hope that a supplement that's supposed to increase fatty acid oxidation would increase and lower them, respectively, didn't budge.

The more choline the better the carnitine retention. The question is however: If the levels already increased and there still was no effect - would adding choline actually make a difference?

Bottom line: The good news is that vegetarians can easily compensate their lack of dietary carnitine by supplementing with 2g of l-carnitine tartrate per day. The bad news is that this is without consequences on any of the relevant metabolic and/or performance markers.

In view of the fact that the l-carnitine was consumed immediately after breakfast and dinner, i.e. in a period where insulin was high and could help shuttle the carnitine into the muscle, it's questionable whether the addition of choline, of which you as a SuppVersity reader know that it increases the muscular carnitine retention, would have yielded significantly different results. It may have helped to elevate the carnitine levels in the muscle of the omnivore control subjects, but it's unlikely that it would have changed the non-existent effects the increase in muscular carnitine pools in the vegetarians had on their metabolism and physical performance | Comment on Facebook!

References:

• DiNicolantonio, James J., et al. "L-carnitine in the secondary prevention of cardiovascular disease: systematic review and meta-analysis." Mayo Clinic Proceedings. Vol. 88. No. 6. Elsevier, 2013.
• Koeth, Robert A., et al. "Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis." Nature medicine 19.5 (2013): 576-585.
• Micha, Renata, Sarah K. Wallace, and Dariush Mozaffarian. "Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus a systematic review and meta-analysis." Circulation 121.21 (2010): 2271-2283.
• Novakova, Katerina, et al. "Effect of l-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians." European Journal of Nutrition (2015): 1-11.
• Wang, Zeneng, et al. "Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease." Nature 472.7341 (2011): 57-63.

Combinations that Work: HMB & Isometric Training for Lean Mass, Creatine & Powerlifting for Leaning Out and Carnitine & Bodybuilding for Powerlifting?

Image 1: Jacek Spychala - I must admit, I don't know if he was one of the subjects, but 38 of his colleagues from the Polish National Powerlifting Team were (powerlifting.pl)

As an athlete and even as a regular fitness enthusiast, you got to chose your training and supplementation modalities according to your professional or personal goals (in fact, the failure to do so is, in my mind, one of the main causes why so many trainees do not get the desired results at the gym). A very recent study from the Department of Combat Sports and Weightlifting at the Józef Pilsudski University School of Physical Education (I wish every University had such a department ;-) in Warsaw, Poland, sheds some light onto combinations which work, and combinations which don't... and trust me you will be surprised by the results of Dr. Marek Kruszewski's controlled intervention study (Kruszewski. 2011).

Kruszewski recruited recruited a total of 170 (! that alone is noteworthy !) subjects who participated in a three-tier placebo-controlled study on the effects dietary supplementation of l-carnitine, creatine and HMB combined with different modes of strength training (bodybuilding type circuit training, powerlifting and isometric training) had on muscle strength, lifting performance and body composition (for a graphical overview of the study design see figure 1).

Figure 1: Graphical illustration of the three tiers (l-carnitine, creatine, HMB), general information and detailed information on the exact exercise protocol of the isometric workout of the HMB group

Not only the sheer size of the study with active and placebo groups of ~30 previously untrained subjects, each, in the l-carnitine and HMB tier of the study are impressive, the participation of 38 powerlifters from the Polish National Team (cf. video of Daniel Grabowski, with a 2254lbs total) is, as well. If each group had received all three of the supplements subsequently and body composition had not been measured with an expensive but still not 100% accurate body impedance device, this study would have been the equivalent of the egg-laying-wool-milk-sow of the Natural Rythmicity for Maximum Fat & Minimal Muscle Loss episode of the Intermittent Thoughts, but I guess we cannot have it all ;-)

2g HMB + isometric training for lean muscle gains!

Image 2: HMB is getting
cheaper, lately

I thought, I'd give the most "exotic" training variety (isometric training) the advantage and tell you about the effects 2g of HMB per day (4 servings of 500mg; one with breakfast, one before, one after the workout and one in the evening; for 5 weeks = 20 training sessions) had on the strength performance and body composition of 69 previously untrained, strength trainees -  not only to raise the awareness that isometric contractions could be a valuable addition to everyones regime (something my friend Rob Regish also advocates in his Blueprint), but also because the effects observed in this tier of the study were, as Kruszewski points out, "[t]he most distinctive and desirable" ones:

Although this type of supplementation [HMB] was used in the group of subjects who trained using the isometric method, regarded as a training system not associated with increases in lean body mass (LBM), the obtained results indicate that HMB may also affect LBM. In view of the fact that LBM involves mainly muscles containing about 70% water, the demonstrated significant elevation of LBM accompanied by the reduced water content in the bodies of the examined competitors is difficult to explain.

Now, I've got you listening my iron-friends, don't I? Increased lean mass (+1.31kg), decreased (as the author points out, later) "presumably extracellular" water - sounds like it was coming from a competitive bodybuilder's "dry dreams", doesn't it? Well, the one thing that would be missing now, is a way to get rid of the fat - but wait, weren't there other supplements in the study, as well?

10g Creatine (+10g dextrose) + powerlifting for fat loss!

Image 3: Creatine monohydrate
for fat loss? That's a surprise.

Yes, there were, and believe it or not, not l-carnitine and circuit training, but creatine and powerlifting will shed the fat - even in elite level powerlifters! By continuing their regular (pyramid style, cf. figure 1) powerlifting training, the 16 power lifters from the Polish National Team, who received the 20g/day creatine + dextrose combination did not only improve their powerlifting performance by a statistically significant +15.6kg over the placebo group, they also and, as Kruszewski points out, "surprisingly" lost a significant amount of body fat in the course of the 20 training sessions they completed within the 5 week study period:

[...] the present results indicate that supplementation with this compound [creatine] led to a significant reduction in the fat content and increase in the water content of the organisms of powerlifters from the Polish National Team.

In view of the results, the author observed in the last group, the one which did a bodybuilding-type circuit training that was supplemented with 900mg of l-carnitine l-tartrate per day (cf. figure 1), I find it pretty amusing that according to Kruszwski the "effect of creatine may be much more far-reaching than that indicated in the manufacturers’ leaflets", which is something, he certainly would not say of l-carnitine.

900mg l-carnitine l-tartrate + "bodybuilding-type" circuit training for powerlifting? 

Image 4: L-carnitine alone will not transform your physique like this magic mirror - no matter what the advertisement leaflet in the latest muscle mag says ;-)

The results in the l-carnitine supplemented group (3x300mg l-carnitine l-tartrate) were mixed. While the previously untrained subjects obviously gained strength in the course of the 15 workouts they performed in the 5 week study period, there were huge intergroup differences - meaning that a few subjects appeared to benefit from carnitine, while the majority didn't. Moreover, fat loss or beneficial changes of body composition, which is what l-carnitine is marketed for, were completely absent in the l-carnitine group. And while the training intensity was pretty low (although the trainees had to perform the 3rd of their three training circles to complete failure) this does not really surprise me, as the "fat burning" effect of oral carnitine supplementation has been debunked by more than a dozen well-designed studies, so that you better follow Kruszewski's advice and "treat advertisements of this compound [l-carnitine] with reserve" ;-) He goes on to explain that...

[...i]t is possible that individuals with inherited or acquired L-carnitine deficiency manifested by increased deposition of fat in the body may benefit from such supplementation and improve their body composition by consuming appropriate amounts of this substance accompanied by proper (predominantly aerobic) exercising. However, additional L-carnitine supplementation in individuals with normal production and concentration of this substance in the body is superfluous.

On the other hand, Kruszewski admits that despite the absence of significant improvements in muscle torque, the powerlifting performance of the subjects in the l-carnitine group increased statistically significantly more than the one in the placebo group (+13.7kg) which is ...

surprising in view of the fact that such an effect [increase in powerlifting performance] of L-carnitine has very rarely been reported and emphasized.

He goes on to suggest that these improvements may be related to l-carnitines impact "on the general physical fitness of the organism". Yet, whatever the reasons may be - out of this triumvirate, l-carnitine would certainly be the least effective addition to your regimen - whatever your goals may be.

Isometric training and HMB supplementation, on the other hand, emerge as as surprise winner. With statistically significant (+17.7kg) increases in power-lifting performance, significant increases in muscle torque, and a +1,31kg increase in body mass (predominantly lean muscle) that was accompanied by a likewise significant reduction in extracellular water, it may be a good idea to take advantage of the falling HMB prices (buy in bulk!) and to incorporate some isometric exercises into your workout regimen ... what do you say?

L-Carnitine Works! At Least if it's L-Carnitine L-Tartrate.

Initially, carnitine was considered the super-supplement for both, the athlete seeking the ergogenic edge, as well as for the obese trying to shed unhealthy body fat. Surprisingly, however, study after study showed no to little effect on exercise performance and/or fat loss. Ultimately, it became clear that, even at very high doses, only very little of the orally delivered l-carnitine actually makes it to the muscle. Consequently, its effects on performance and body composition where negligible. Now, a very recent study by Wall et. al. (Wall. 2011) found that adding a transporter, in this case l-tartrate, to the molecule does not only help to increase muscle carnitine levels, it eventually produces exactly those effects on exercise performance and substrate metabolism one would have expected from l-carnitine supplementation in the first place.

The scientists had their 14 healthy male volunteers ingest either 80 g of CHO (Control) or 2 g of L-carnitine L-tartrate and 80 g of CHO (Carnitine) twice daily for 24 weeks in a randomised, double blind manner. Other than in previous studies with plain l-carnitine (minus the l-tartrate) there was a significant increase of muscle carnitine content with all the downstream metabolic benefits on exercise performance one would expect:

Muscle TC increased from basal by 21% in Carnitine (P<0.05), and was unchanged in Control. At 50% VO2max, the Carnitine group utilised 55% less muscle glycogen compared to Control (P<0.05) and 31% less pyruvate dehydrogenase complex activation (PDCa) compared to before supplementation (P<0.05). Conversely, at 80% VO2max, muscle PDCa was 38% higher (P<0.05), acetylcarnitine content showed a trend to be 16% greater (P<0.10), muscle lactate content was 44% lower (P<0.05) and the muscle PCr/ATP ratio was better maintained (P<0.05) in Carnitine compared to Control. The Carnitine group increased work output 11% from baseline in the performance trial, while Control showed no change.

So, after all, it was not the wrong the substance previous investigations used, but rather the wrong form - l-carnitine l-tartrate - though expensive - is the way to go to burn fat and increase athletic performance. If you do not want to buy it in bulk, I suggest you at least buy a product like MAN Sports Body Octane, where you actually know how much (here 1g) of the carnitine you're getting per serving.