Leucine: the muscle powerhouse

Article by Caitlin Arnold, a vegan Accredited Sports Nutritionist, Strength & Conditioning coach and bodybuilder at Plant Physique. Her passion is helping vegans achieve their health and fitness goals with evidence-based guidance and expertise. 

What Is Leucine and Why Is It Important?

Leucine is one of nine essential amino acids that our body must obtain from food.

It is most well known for its muscle-building properties – specifically as a catalyst for muscle protein synthesis. So when it comes to growing muscle, if you don’t have enough leucine it’s like trying to start a car without a key.

Leucine is most prominently found in animal-products, like chicken, beef, pork, tuna, dairy and eggs. So for non-vegan bodybuilders and strength athletes, leucine isn’t something that they need to focus on.

Consequently, leucine is not a well known topic because getting enough leucine happens easily for meat-eaters.

But vegetarians and vegans should take care to get consistent and adequate doses of leucine to optimise their muscle growth, repair, and recovery.

How Much Leucine Do Athletes Need?

To optimise muscle growth, you want to eat an adequate amount of protein each day split relatively equally across 3-6 meals, with 2.5-3g of leucine in each of those meals.

But unlike animal proteins, the challenge is that plant proteins often have less than 1g of Leucine.

Frequency & Dosage is Key

Best Plant-Based Sources of Leucine

Thankfully, there are a few exceptions. Primarily, these are soy-foods and some legumes which have slightly higher quantities of leucine:

• 150g of firm tofu has roughly 2.5g
• 50g of raw textured vegetable protein (TVP) has 2g
• 1 cup of cooked soy, haricot, or adzuki beans has 1-1.6g
• 40g of Soy Protein Isolate has 3g
• 100g of Vital Wheat Gluten has 5.4-6.8g (like this Seitan Steak recipe)

Include soy-foods regularly in your diet each day to ensure you’re consuming leucine regularly.

Supplementing with Leucine

The reality is that most people don’t consume soy in every meal. This makes it difficult for vegans who are trying to build muscle to get enough leucine and frequently enough to optimise their muscle growth.

A solution is to supplement with 2-3g of leucine powder at each main meal that doesn’t contain soy. This could be useful primarily for vegan athletes and those wanting to make sure they’re getting as much muscle growth as possible.

Some vegan Leucine products include:

• Bulk Nutrients L-Leucine Powder
• NOW Foods, Sports L-Leucine Powder
• EVLution Nutrition L-Leucine2000
• AminoZ L-Leucine

Key Takeaways

Leucine is one of nine essential amino acids that our body must obtain from food. When it comes to growing muscle, if you don’t have enough leucine it’s like trying to start a car without a key.