Why is Leucine so Important?


As mentioned in my previous posts (here and here), there are 20 amino acids (AAs) the body utilizes.  Nine (9) of those are the essential AAs while the other 11 are the non-essential AAs.  Among the essential AAs, leucine tops the charts and has been the most researched branched-chain AAs (BCAAs) out there.  It has been known for it’s muscle protein synthesis properties within the bodybuilding world, thus receiving most of the credit to keep those pumping muscles growing!  Here’s some information on what leucine has offer in order to keep those muscles strong and growing when we perform our workouts…

What does leucine actually do for us?

In the research, leucine has shown to have positive properties to aid in muscle protein synthesis (aka muscle growing properties).  Leucine is part of the top three researched BCAAs with isoleucine and valine – but leucine has shown the strongest properties to keep muscle protein stimulation the highest, especially if one’s supplements with it before/during/after a workout!  Leucine highly activates a pathway within the muscles of our bodies called mammalian target of rapamycin, or mTOR.

Mammalian target of rapamycin serves as direct sensor towards leucine – like they say…opposites attract!  When mTOR gets fed by leucine, it creates a flood gate for muscle protein synthesis to occur and to happen faster in order to feed the muscles!  So the more leucine we have available, then the more mTOR pathways can be signaled then…you guessed it…muscle gets built!

How much leucine should I have in my nutrition plan?

Recent recommendations of oral leucine supplementation has shown equal if not superior effects to stimulating muscle protein synthesis than supplementing with whey protein alone.  Use of leucine alone can create the muscle growing effects you expect to see, based on the current research out there.  Here’s some recommended doses from some of the experts:

  • Consume 2.5g (or 5g of total BCAA) within 30 minutes of your workout
  • Consume 5g of leucine (or 10g of total BCAA) in your post-workout shake
  • Consume 5g of leucine before bedtime
  • Consume 2-3g of leucine in between meals

Please note, that you can choose whichever recommendation you’d like as stated above.  I personally like to consume my BCAAs during my workouts and then finish it off after completing my workouts.  There are at times during my work schedule that I will utilize BCAAs in my coffee in the mornings or in some water in the afternoon – it all depends on how I’m feeling that day.  So choose a program that fits your schedule and get that leucine (or BCAAs) in!

What supplement do you recommend trying out?

I’m a big fan of Optimum Nutrition Essential Amino Energy – concord grape and blue raspberry flavor are my favorites!  I’ve tried some others out there including SciVation Xtend BCAAs and BPI Sports Best BCAA but they just don’t fit my tasting – I tend to go for the sweet stuff!  I recently just added Carbon Recover by Layne Norton, where I consume after really intense workouts and know that my body will be more sore than usual the following day.



If you’re tired of just drinking water during your workouts, then try drinking BCAAs with your water instead!  You know that you are constantly feeding your body to help grow those muscles and also stimulate the healing process too – that’s what we do when we workout….we essentially break down our muscle tissue and then rebuild it!  Do some shopping around and test out some leucine/BCAAs products and see what you like best!  Happy eating and remember to enjoy the process in whatever your work may be!  #teambullseyenutrition


  1. http://www.bodybuilding.com/fun/layne39.htm
  2. http://www.bodybuilding.com/fun/supplemental-leucine-how-it-powers-muscle-growth.html
  3. https://www.ncbi.nlm.nih.gov/pubmed/10418071
  4. https://www.ncbi.nlm.nih.gov/pubmed/16265600
  5. https://www.ncbi.nlm.nih.gov/pubmed/20601741

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