Research shows that leucine and its two much talked about metabolites, alpha ketoisocaproate, or KIC, and beta-hydroxy-beta-methylbutyrate, or HMB, spare muscle proteins in humans. Leucine is one of three branched-chain amino acids, or BCAAs, and, along with the other BCAAs,
isoleucine and valine, it's involved in muscle protein growth. Leucine's derivatives KIC and HMB are enjoying rising popularity among bodybuilders looking to build mass and strength.
The BCAAs aren't as hightech and new as KIC or HMB, but they still play an important role in sports pharmacology as they help increase muscle protein biosynthesis. During high-intensity exercise your body uses up more leucine than any other amino acid. A bodybuilder training with
high intensity and heavy poundage may require a mini mum of 80 milligrams per kilogram per day of leucine. For a 200-pound lifter the minimum dose should be 5.5 to seven grams a day. Taking leucine, isoleucine and valine one hour before training may provide a moderate anabolic
and muscle-sparing effect, and a well-trained strength athlete can benefit from taking them both before training and in the early stages of recovery.
Leucine is changed into its ketoacid KIC, which then enters muscle mitochondria or the cyrosol of the liver for further changes. Studies have shown that KIC has beneficial actions on the body, including increased muscle protein synthesis, antioxidant action, improved nitrogen
balance, fat loss, HMB synthesis, insulin release, anticatabolic action, ammonia scavenging and immune system stimulation.
One of the most significant actions of MC may be in its ability to suppress ACTH and cortisol. As most athletes know, cortisol is a catabolic hormone that can destroy muscle protein synthesis. Since research has shown that KIC reduces the harmful effects of cortisol, this supplement
gives you another powerful anticatabolic agent. MC, along with other known anticatabolics such as phosphatidylserine and certain antioxidants, is recommended for intermediate and elite-level strength athletes to reduce muscle tissue damage, speed recovery and create the maximum
How much KIC do you need to get a significant anabolic benefit? Two to three grams a day is plenty. The best time to consume MC is right after a workout, during your short-term recovery from training, when the anabolic processes are building. Beta-Hydroxy-BetaMethylbutyrate. The
new kid on the leucine derivative block is a lesser known catabolite, beta-hydroxy-betamethylbutyrate, or HMB. We're only beginning to see research about this compound, hut we do know that HMB is produced from leucine, which means that if you consume leucine, you are in fact making
some HMB. In addition, recent studies clearly show that HMB can be derived 100 percent from KIC, so if you consume MC, then your HMB levels will rise as well. One animal study showed that HMB levels increase by as much as 400 percent when KIC is added to the diet.
Preliminary studies using HMB with weight-trained athletes showed that it helps increase strength and lean muscle mass. One of the companies that sells HMB is Metabolic Technologies, which recommends that lifters consume three grams a day for 60 days to achieve long-term anabolic
The Bottom Line on Leucine Derivatives
So what's the best form of leucine to use? Research shows that the branched-chain amino acid itself is a valuable supplement for athletes involved in strength programs, and the body converts it to KIC and HMB. So a combination of all three BCAAs would seem to be a smart choice.
A dosage of six grams of leucine, two grams of isoleucine and five grams of value a day is optimum when you're training hard. Break it up so you take about one gram of leucine, 200 milligrams of isoleucine and 800 milligrams of valine before each workout and immediately following
training. The cost for a daily dosage of BCAAs is about 80 cents.
When using KIC, you need to take two to three grams daily to experience the many anabolic and anti- catabolic effects. MC is more expensive than leucine and will cost you about $1.50 per day. As for HMB, as indicated above, there's not much peer-reviewed scientific Literature
available to support it yet, and what new research there is on HMB is courtesy of grants from the company that sells it. Obviously, we need more research on this supplement so we can compare it head to head with MC.
HMB is pricey and will cost you twice as much as KIC, about $3.50 per day. Since HMB is made from KIC, and there's a great deal of positive scientific data to support ICC, you'll have to ask yourself what you get for the higher price. That's not to say that HMB is worthless, it
is a useful leucine derivative and not a metabolic end product. Sports nutrition has evolved rapidly over the past few years, giving well-trained drug-free bodybuilders a greater ability to rise to elite levels.
Make no mistake about it, however, the proper use of advanced sport nutrition is a planned and predictable process, and supplements like ICC are tools that must be used in combination with a carefully planned diet and training program.