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Supplement Facts & Directions

Supplement Facts

Serving Size: 1500 milligrams
Servings Per Container: Varies
Amount Per Serving % Daily Value*
L-Leucine 1500 mg

* Percent Daily Values are based on a 2,000 calorie diet.
† Daily Value Not Established
‡ These supplement facts may vary from the product you receive. Please call for exact numbers.

Other Ingredients: None


Free of: Added Sugar, Soy, Dairy, Yeast, Gluten, Corn & Additives.

Directions: As a dietary supplement, take 1500 mg twice daily or as directed by a physician. An accurate gram weight scale is recommended.

Warning: If you are pregnant, nursing, taking any medications, or have any medical conditions consult your physician before use. Keep out of reach of children.

Product Details

What is L-Leucine?

L-leucine, or simply leucine, is an essential amino acid and one of the three branched-chain amino acids (BCAAs), along with l-valine and l-isoleucine. Leucine is one of two exclusively ketogenic amino acids, with the other being lysine. Ketogenic amino acids can degrade directly into acetyl coenzyme A (acetyl-CoA). The body needs Acetyl-CoA to metabolize macronutrients, including carbohydrates, proteins, and fats. It also plays a role in the citric acid cycle by donating its acetyl group for oxidation into energy.

The human body cannot synthesize leucine and requires dietary sources to meet its nutritional needs. Leucine-rich foods include beef, pork, chicken, tuna, cheese, milk, beans, and tofu. Vegans may have a hard time consuming adequate leucine, as many of the food sources are animal-based.

What Are BCAAs?

BCAAs facilitate muscle growth by activating protein synthesis. BCAAs account for 35% of the essential amino acids in muscle proteins and 40% of the amino acids required by human metabolism. All BCAAs include a side chain attached to their chemical structure hence the designation branched chain.

Potential Leucine Benefits

Leucine and Muscle Growth

Leucine is the most potent of the three BCAAs when it comes to protein synthesis. Multiple studies found that BCAA supplements with a higher ratio of leucine promote more protein synthesis for greater muscle growth. Leucine has also shown the potential to decrease appetite and body adiposity. It promotes muscle recovery as well and may inhibit anabolic resistance. Anabolic resistance reduces muscle protein synthesis stimulation and contributes to the loss of muscle tissue. Leucine may also help reduce muscle loss due to illness or aging.

Leucine and Resveratrol

Leucine and resveratrol both stimulate mitochondrial biosynthesis by activating SIRT1 proteins. Taken together, they synergize to produce even greater longevity-enhancing effects.

Leucine and Longevity

Leucine may promote longevity and overall health by activating sirtuin proteins (SIRT1). Researchers believe that SIRT1 activation is a pro-longevity mechanism. Resveratrol, another longevity-enhancing supplement, uses the same mechanism to exert its effects. Leucine is also the most probable compound that explains the health benefits of dairy proteins. One study noted that participants consuming a dairy-rich diet had more SIRT1 activity by 13% in fat cells and 43% in muscle tissues. Leucine also triggers mitochondrial biogenesis, a process that improves mitochondrial function and reduces the damage caused by mitochondrial dysfunction. The latter is particularly important, as mitochondrial dysfunction is one of the primary hallmarks of aging.

Potential Leucine Side Effects

Some individuals may experience nausea or indigestion while taking leucine supplements. Leucine may interact with certain medications and medical conditions. Individuals taking medication for high cholesterol, thyroid conditions, or diabetes should consult with their physician before taking leucine supplements. Individuals with low niacin (vitamin B3) or maple syrup urine disease (MSUD) shouldn’t take leucine supplements.


Tested by Accredited 3rd Party Labs

PureBulk's supplements are tested by accredited third party labs in the USA to ensure their identity, purity and potency. To receive a copy of these test results or any other PureBulk supplement please fill out the COA request form found here.

*NOTE: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

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