Leucine is an essential amino acid known for stimulating muscle protein synthesis and increasing lean body mass. Although BCAAs or Branch Chain Amino Acids contain leucine they are also made up of are made up of two other amino acids, Isoleucine and Valine, but clinical studies have shown Leucine to be the most effective.
Leucine Increases Lean Body Mass
In 2015 a meta-analysis on leucine’s ability to increase lean body mass analyzed 16 studies enrolling a total of 999 subjects and concluded that leucine supplementation significantly increased lean body mass.
This increase in lean body mass has been credited to leucine’s ability to increase muscle protein synthesis similar to the level of whey protein without taking in any calories. One 2014 study showed that a daily dose of 5g of leucine increased muscle protein synthesis to the same level as 25g of whey protein, even 4.5 hours after exercise
Leucine Increases Muscle Protein Synthesis
Leucine has been accredited as a key fasted workout supplement, preventing your body from entering a catabolic state where your losing muscle. By increasing the amount of protein synthesis your body has a positive muscle protein balance and allows muscle growth to take place.
These findings haven’t been limited to certain ages as several recent studies have found that leucine also These findings haven’t been limited to certain ages as several recent studies have found that leucine also increases the amount of mixed muscle fractional synthesis in older populations as well. This increase in protein and muscle synthesis stimulates muscle growth to overcome the anabolic resistance of aging .
Increasing your anabolic level with leucine supplementation, has been shown to significantly increase isometric leg strength especially for older users.
This increase in muscle protein synthesis (MPS) that leucine supplementation provides not only results in strength and lean muscle gains, but also enhances muscle recovery along with improving athlete performance .
In a 2006 study published in the European Journal of Applied Physiology competitive canoeists supplementing with leucine experienced significant increases in power, endurance, and experienced less fatigue than the placebo group.
Research on Isoleucine and Valine has shown less promising data, with isoleucine increasing glucose uptake in animal models , but research showing these same benefits in humans is lacking .
For this reason, you will often see a ratio like (2:1:1) on the nutritional facts label showing the amount of Leucine is in the BCAA blend. Although, many BCAA products provide a dose of leucine, due to including isoleucine and valine your body’s ability to absorb the leucine is limited.
Why You Should Only Take Leucine and Not BCAAs
Research dating as far back as 1966 has shown that the three components of BCAAs compete for absorption in both in vivo and in vitro studies. One study demonstrated that Isoleucine and Valine inhibit the absorption of leucine and vice versa, but unfortunately our bodies enzymes prefer binding to Isoleucine and Valine over Leucine resulting in our bodies only absorbing a fraction of the most effective component in the BCAA complex. This is why Muscle and Joint Recovery™ only contains an effective dose of Leucine.
How Leucine Works
Leucine is metabolized in the liver and in muscle cells where the majority of it is broken down into acetoacetate and acetyl coenzyme A along with a small portion (2-10%) taking form as HMB (β-Hydroxyl- β-methyl butyrate).
Acetyl-coenzyme A is the main product of the breakdown of leucine and serves an important role in many biochemical reactions involving the metabolism of protein, carbohydrates and lipids, but is most wildly known due to its role in producing a high level of energy via the Krebs Cycle. Due to the cleavage of a highly exothermic bond, a single acetyl group yields 11 ATP which is immediately utilized by your muscles during intense exercise.
Acetyl-Coenzyme A is the reason behind the increases in protein synthesis, lean muscle gains, and enhanced performance associated with leucine supplementation.
What about HMB?
The secondary product of this process, HMB is a molecule that has recently been incorporated into more and more pre- workout formulas. HMB has been proposed to increase the amount of skeletal muscle while also increasing strength and power, and although some studies have supported this claim, most of the benefits were limited to untrained individuals as HMB supplementation showed a low effectiveness in strength-trained athletes low effectiveness in strength-trained athletes .
Due to providing an sonly a benefit to a handful of users , along with studies demonstrating a benefit having mythological flaws, we have decided not to include HMB as an ingredient