Carnitine L-Tartrate Supplementation for Powerlifters: The Science Behind the
Hype
By
Joseph Crozier
Like thousands of others, I was looking for a magic bullet, a secret
supplement no one else was taking, that would lead me to newfound levels of
strength and athleticism. When I read that l-carnitine l-tartrate (LCLT) could
help me burn fat, recover from exercise, favorably affect my hormone levels, and
deliver more oxygen to my muscles, I was intrigued.
When I read that all of this was backed up with peer-reviewed academic
research, I drove to my local GNC and laid my money on the table. It was only
then that I decided to read the research myself and only then that I discovered
that all the research was funded by Lonza, a company that manufactures LCLT. So,
is LCLT research biased? From what I’ve found, it is, but that doesn’t
necessarily mean it’s wrong. In this article, we’ll take a look at what LCLT is,
why powerlifters specifically may or may not want to take it, and what current
science there is to support this conclusion.
Carnitine is responsible for the transport of long-chain fatty acids (or,
simply put, fat) into the energy producing factories of your cells known as the
mitochondria (1). Theoretically, l-carnitine could be taken in supplement form
to aid in fat metabolism. However, research on the subject has had mixed
results. One problem is that l-carnitine is not easily storable in its natural
form. It attracts moisture and is easily degraded. A possible solution for this
problem is to use l-carnitine l-tartrate, a salt of l-carnitine, which is stored
more easily as a solid. Within the past few years, several key studies have been
published by the University of Connecticut on the use of LCLT as a
performance-enhancing supplement, all of which yielded promising results.
Over the past six years, a series of four research reports were published in
various academic journals on the effects of LCLT. The reports covered a range of
topics such as hormonal responses to resistance exercise (2), recovery from
exercise stress (3), muscle oxygenation (4), and varying doses of LCLT that may
be effective (5). However, all of the studies shared similar themes that need to
be examined more closely when applying the findings to athletes in our sport.
In every report, athletes performed 15–20 repetitions of the squat exercise
at a resistance equal to 50 percent of their one repetition maximum (1RM).
Subjects performed all reps on the Plyometric Power System, which is very
similar to a Smith machine. All participants had experience with the squat
exercise for at least one year prior to testing, and all participants were of
similar age. In every report, 8–10 athletes were included. Furthermore, in three
of the reports, subjects took 2 grams of LCLT daily while regularly meeting with
a registered dietician to help standardize dietary behaviors. Lastly, every
report was funded by a grant from Lonza Inc., a company that produces LCLT.
Beyond the conflict of interest present due to sponsorship, the most glaring
problem that I see is sports specificity. Rarely do powerlifters train at 50
percent of their 1RM for 15–20 repetitions, and, if training is performed at a
heavier load, how will that affect LCLT use? In fact, the authors specifically
chose a load of 50 percent because “excessive muscle damage might affect
capillary integrity and subsequently mitigate the effects of LCLT on muscle
blood flow” (4). Simply put, if you plan on doing any actual powerlifting, LCLT
may not work at all.
Another important factor to consider is that subjects were regularly meeting
with dieticians and
consistently performing exercise testing three hours after lunch. This is
important when you consider that muscle, carnitine use, and fat oxidation rates
are lower during exercise with higher muscle glycogen (carbohydrates stored in
the muscle) (6). Because many well-fed powerlifters are carrying extra muscle
glycogen, this may limit the effectiveness of supplemental carnitine as well.
This, in fact, is the most important concept—l-carnitine is certainly
involved in fat oxidation in muscle cells. The only question is whether typical
well-fed athletes will absorb the LCLT and use it to increase performance.
According to the University of Maryland Medical Center, carnitine is produced in
the liver and kidneys by breaking down the amino acids lysine and methionine
(1). These amino acids are found in many foods including meat and cheese. In
addition, up to 75 percent of dietary l-carnitine may be absorbed from food in
contrast to only 5–18 percent of l-carnitine in supplement form (7). On top of
these statistics, athletes whose dietary fat levels vary may not be the best
subjects for carnitine supplementation research (8).
So, back to our main question…should powerlifters supplement with LCLT? For
lifters with deficiencies in some key amino acids or muscle glycogen, those
carefully monitoring their dietary fat, or those who don’t plan on doing fairly
intense and heavy lifting, LCLT supplementation could help. Otherwise, there are
more effective supplements no matter what
Lonza might tell you.
References
1. Debusk R (2002) Carnitine (L-Carnitine). Retrieved: January 2, 2009.
From: University of Maryland Medical Center website
http://www.umm.edu/altmed/articles/carnitine-1-000291.htm.
2. Kraemer WJ, Volek JS (2003) The effects of L-Carnitine L-Tartrate
supplementation on hormonal responses to resistance exercise and recovery.
Journal of Strength and Conditioning Research 17(3):455–62.
3. Volek JS, Kraemer WJ (2002) L-Carnitine L-Tartrate supplementation
favorably affects markers of recovery from exercise stress. American Journal of
Physiology: Endocrinology and Metabolism 282:474–82.
4. Spiering BA, Kraemer WJ (2008) Effects of l-carnitine l-tartrate
supplementation on muscle oxygenation responses to resistance exercise. Journal
of Strength and Conditioning Research 22(4):1130–35.
5. Spiering BA, Kraemer WJ (2007) Responses of criterion variables to
different supplemental doses of L-Carnitine L-Tartrate. Journal of Strength and
Conditioning Research 21(1):259–64.
6. Roepstorff C, Halberg N (2004) Malonyl-Coa and carnitine in
regulation of fat oxidation in human skeletal muscle during exercise. American
Journal of Physiology: Endocrinology and Metabolism 288:133–42.
7. Evans AM, Fornasini G (2003) Pharmacokinetics of L-Carnitine.
Clinical Pharmacokinetics 42(11):941–67.
8. Ransome JW, Lefavi RG (1997) The effects of dietary L-Carnitine on
anaerobic exercise lactate in elite male athletes. Journal of Strength and
Conditioning Research 11(1):4–7.
Joseph Crozier is a competitive powerlifter and personal trainer. He holds
the APA-WPA 20–23-year-old, 165-lb raw world record in the squat, deadlift, and
total. In the USPF competition, he deadlifted 545 lbs at 165 lbs, conventional
and raw. Joseph has his bachelor’s degree in exercise physiology from California
State University (CSU), Chico and is currently in the masters of kinesiology
program there as well. He also works as a personal trainer at FitOne Athletic
Club in Chico, California, and teaches intermediate weightlifting classes at
CSU, Chico.
Elite Fitness Systems strives to be a recognized leader in the strength
training industry by providing the highest quality strength training products
and services while providing the highest level of customer service in the
industry. For the best training equipment, information, and accessories, visit
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