Two grams L-carnitine daily protects athletes' muscles
A daily dose of 2 g L-carnitine protects athletes' muscles from breaking down, according to a human study that sports scientists at the Islamic Azad University in Iran published in the Asian Journal of Sports Medicine. Whether the anticatabolic effect of L-carnitine speeds up muscle building? The researchers did not look at this, but who knows...

L-Carnitine
Your body's cells convert nutrients into energy in their mitochondria. You could say that mitochondria are molecular power plants. And if mitochondria are power plants, then L-carnitine molecules are the trucks that transport the coal fermentable biomass. That's why sports scientists are so interested in L-carnitine supplementation.

Study
The researchers divided 22 physically active young men into two groups. One group took a placebo for two weeks; the other group took a supplement containing 2 g L-carnitine. At the end of the two weeks the researchers got the men to run for 15 minutes.

The researchers also analysed the subjects' blood: before supplementation started [Base], just before they started running [Pre], just after they finished running [Post] and again 2 [2 h] and 24 hours [24 h] afterwards.

Results
The running session boosted the concentration of the enzymes LDH and CK in the men's blood, but the increase was noticeably less in the men who had been given carnitine. LDH and CK are markers for muscle damage. It seemed that L-carnitine supplementation reduced muscle damage.

Conclusion
"The present study demonstrates that an acute bout of exercise can induce oxidative stress in active healthy young men", the researchers wrote in the last paragraph of their publication. "Two-week daily oral supplementation with L-carnitine has some alleviating effects on lipid peroxidation and muscle damage indices in favour of increased antioxidant capacity."

Source:
Asian J Sports Med. 2014 Jun;5(2):123-8.