
Resistance training often first comes to mind when it comes to building muscle. However, if you want to build muscle mass and strength successfully, working out is not enough. You need to fortify your efforts with a rich protein source to support its synthesis in the body.
While a balanced diet can ideally support your protein needs, sometimes you need a little extra boost from nutritional supplements. If you’re looking for a way to promote muscle formation in your body, then L-Leucine might just be what you need.
L-Leucine at a Glance

L-Leucine is the dietary supplement form of leucine, a branched-chain amino acid (BCAA) found in protein. It is well-known for its roll in stimulating muscle growth. Compared to other BCAAs like isoleucine and valine, it can activate the growth pathways needed to stimulate skeletal muscle synthesis by up to ten times.
Since it is an essential amino acid, your body cannot produce leucine which means you need to supplement it in your diet by eating protein sources such as egg whites, chicken, beef, pork, tuna, soy-based products, beans, eggs, and dairy products.
Including leucine in your diet, even if you’re not a bodybuilder will help your muscles grow and thrive resulting in many health benefits such as:
- Increased Metabolic Rate. Muscles are known to burn rather than store energy. This means the more lean muscles, you the bigger your energy requirements are. This eventually results in you your body’s burning more fat.
- Ease of Performing Daily Activities. The more lean muscles you have, the stronger you are likely to be. This means you can perform daily tasks more efficiently.
- Better Body Composition. Lean muscles make for an awesome-looking physique. Not only will your body look toned but your clothes will also fit better.
How It Works
Leucine stimulates muscle growth by activating the muscle-building pathway called the mechanistic target of rapamycin or mTOR. The increase in leucine levels in the body signals mTOR to build muscle because there are sufficient nutrients and amino acids to support it.
It should be noted however that you need to reach the leucine threshold if you want your muscles to grow. In other words, you need to have enough leucine to support the growth of your muscles.
L-Leucine Benefits

- Muscle gain. L-leucine is a popular supplement among bodybuilders thanks to its muscle gaining effects. Research suggests that when combined with a good variety of protein-rich food in your diet, supplementing with L-leucine can promote muscle growth and enhance athletic performance.
- Reduced muscle loss. As you age, your skeletal muscles deteriorate which can cause weakness ad decrease stamina. L-leucine helps improve muscle synthesis in older adults which slows down age-induced muscle loss.
- Improved athletic performance. Apart from promoting muscle growth, l-leucine also improves endurance and power in athletes and helps improve functional performance in older adults.
- Improved muscle recovery. People are prone to muscle soreness following intense physical activity. With the help pf l-leucine, your body can recover more efficiently.
- Stabilized blood sugar. Studies are suggesting that l-leucine can play a role in stabilizing sugar levels in the body when taken together with glucose.
Dosage Recommendations
L-leucine is available in doses ranging from 2,000 mg to 5,000 mg. It is usually taken alone or alongside low-protein meals.
When taking l-leucine, it is best to start taking low doses first to assess your tolerance and then work your way up.
Safety Considerations
While consuming leucine supplements is safe and free from side effects, taking it as a supplement entails precaution.
Leucine toxicity can cause delirium and neurologic compromise. High intake of l-leucine can also aggravate the symptoms of pellagra in people with niacin deficiency. Moreover, its high doses of leucine can also increase the levels of ammonia in the blood.