Carnitine is made from the amino acids lysine and methionine, as well as from vitamins C, B3 and B6, and iron. In addition to being a popular fat-burner – it transports fat into the mitochondria of cells, where it’s burned as fuel – carnitine is now known to have many anabolic properties. It can increase blood flow to your muscles, enhance muscle recovery following workouts and increase the amount of testosterone receptors inside muscle cells. The more of these receptors you have, the more likely your testosterone will bind to them and stimulate muscle growth.
FORM: The three most common forms you’ll see are L-carnitine, acetyl-L-carnitine and L-carnitine L-tartrate. L-carnitine is the basic form of the supplement and has been found to enhance fat-burning. Acetyl-L-carnitine (ALC) is present throughout our bodies, especially the central nervous system, and in the brain it provides precursors for the neurotransmitter acetylcholine, which is important for proper brain function and energy-producing reactions. Research shows ALC supplementation can both enhance brain function and protect it against deterioration as you age. It has also been shown to better maintain testosterone levels during physical stress.
ALC is also absorbed into the bloodstream more efficiently than L-carnitine because it passes more freely across cell membranes. As a result, it likely gets into muscle cells more easily than the other forms. You’ll pay for the benefits, though: ALC tends to be much more expensive than the others, yet many bodybuilders believe it’s well worth the extra cash.
L-carnitine-L-tartrate (LCLT) is carnitine and tartaric acid, which is an antioxidant found in grapes and bananas. This form increases blood flow to muscles, enhances muscle recovery and boosts androgen receptor levels. We suggest buying both L-carnitine or LCLT and ALC, and take them according to the following timing suggestions.
TIMING: As with creatine, carnitine is best taken with fast-digesting carbs that boost insulin levels such as white bread, a sports drink or Vitargo (a patented high molecular-weight carb). In fact, research from the UK confirms that taking carnitine while insulin levels are high leads to more of the supplement making its way into your muscles. But you don’t want to eat these types of carbs too often throughout the day because high insulin levels at the wrong time can make you fat. For that reason, taking carnitine with your postworkout shake and carbs is ideal, as is taking a dose when you first wake up to help your body reverse the catabolic state induced by your all-night fast. Immediately preworkout is another effective time to supplement, but since you don’t want fast-digesting carbs at this point, stick with the slow-digesting variety such as oatmeal or whole-wheat bread. This is also a good time to take ALC, which is absorbed better by muscles than L-carnitine or LCLT, regardless of insulin levels. You can use the less-potent versions for your other two daily doses.
SIDEKICKS: Because carnitine depends on insulin to get into muscles, consider taking it with supplements such as cinnulin-PF, alpha-lipoic acid (ALA) and gymnema sylvestre, which can boost insulin release, enhance its actions at the muscle cell and mimic its actions.
Cinnulin-PF is a trademarked water-soluble cinnamon extract with hydroxychalcone, an active ingredient that helps it mimic the effects of insulin in muscle cells. Taking 100-250 mg with carnitine preworkout can increase the carnitine content in muscles without boosting insulin levels at a time when you want them low.
ALA is an antioxidant that enhances insulin’s actions at the muscle cell. Take 300-500 mg with your morning dose of carnitine to aid the uptake of carnitine by the muscles. Gymnema sylvestre should be taken postworkout, when you want insulin levels high. Take 250-500 mg with your carnitine and postworkout meal to further increase the amount of insulin in your blood.
DOSE: The amount of carnitine you take depends on the form. If you’re taking ALC, as little as 1.5 grams per day may be effective because of its enhanced uptake. We suggest you go with 500-2,000 mg per dose for maximum benefit. The research into LCLT has found that just 2 grams per day helps improve blood flow to muscles, muscle recovery and muscle androgen receptor numbers. Stick with 1-2 grams per dose for the best results. To take advantage of L-carnitine’s benefits, we suggest 1.5-3 grams per dose.