Supplements

L-Carnitine Update

Dwayne N. Jackson, PhD

With summer quickly approaching most of us are scrambling to drop those last few pounds that accumulated over winter. Although dieting and caloric restriction is key to achieving a toned physique, they can also make losing fat difficult—leaving you hungry and fatigued.

A study published in the Nutrition Journal recently reported that supplemental l-carnitine blunts hunger and fatigue induced by extreme caloric restriction, resulting in greater weight loss. In this randomized and blinded control trial metabolic syndrome subjects who received l-carnitine (4 g/day intravenous) during a 7-day diet intervention lost over 3 lbs more than those in the placebo group. These results were coupled with measures of better insulin regulation and decreased feelings of hunger and fatigue during fasting in the carnitine group.

ACTION POINT: This latest study provides another scientific reason to use l-carnitine supplements to help with weight loss. Although they used intravenous delivery of l-carnitine in this study, several other investigations show that special forms of l-carnitine like acetyl-l-carnitine (ALCAR) or l-carnitine l-tartrate (LCLT) have high oral bioavailability. We recommend taking 2-3 grams of ALCAR or LCLT, 2 to 3 times daily between meals. On training days, take 1 dose post-workout with a protein shake or meal.

Recover and Reload with CLA

Conjugated linoleic acid (CLA) supplements are generally touted for their fat-burning properties, but the most recent data published in the Journal of Sports Sciences shows that CLA is far more than just a weight loss aid.

In a recent placebo-controlled, cross-over trial, scientists from Taiwan reported that subjects who took CLA for 8 weeks (3.8 g/day) had a 75% greater increase in glycogen storage after a single (60-minute) bout of high-intensity cardio exercise followed by a high carbohydrate reloading meal. This finding was supported by a 79% increase (over placebo) in the immediate post-exercise insulin response and a 150% increase in immediate post-exercise muscle glucose transporter type 4 (GLUT 4) expression—GLUT 4 expression remained elevated by 56% over placebo at 3 hours post-exercise.

What does this mean for bodybuilders? Well, first, CLA seems to boost the insulin response after exercise—insulin is a key regulator for transporting glucose and other nutrients into muscle cells.  Second, elevated GLUT 4 combined with high insulin will ensure heightened glycogen storage in fatigued muscles. This sets up a condition for faster recovery. Finally, these data suggest that CLA might enhance carbo-loading strategies commonly used during bodybuilding contest preparation.

ACTION POINT: In line with this study, we generally prescribe taking up to 2 grams of CLA, 3 times daily with meals. On training, days take 1 dose immediately after training with your protein shake and 25-60g of fast sugar like dextrose.