What is the mTOR Pathway and Why It is Important

Spend any time looking up how to build muscle fast and you’ll undoubtedly come across something called the mTOR pathway.


But, what is it? Why is it important? And, how do we activate it?


Let’s discuss…

What is the mTOR Pathway?

mTOR stands for mechanistic target of rapamycin. Formerly, mTOR stood for mammalian target of rapamycin.


The mTOR pathway is a protein kinase that plays a key role in mammalian metabolism and physiology, affecting functions and tissues within the liver, brain, brown and white fat, and (of course) muscle.


Kinases are enzymes that catalyze the phosphorylation of serine, threonine, or tyrosine groups in enzymes or other proteins, using ATP as a phosphate donor.


ATP Molecule


Certain diseases, such as diabetes, obesity, depression, and certain cancers can cause dysregulation of the mTOR pathway.

Why is the mTOR Pathway Important?

mTOR regulates cell growth, proliferation, and motility, and is critical to cell survival. It also increases ATP production and creates new mitochondria as well as boosts mitochondrial metabolism.


mTOR also regulates transcription, the initial step in gene expression, and autophagy, a cleanup and recycling mechanism within our cells


mTOR is divided between two complexes mTORC1 and mTORC2, and they are involved in various aspects of growth, metabolism, and disease.


mTORC1 controls the balance between anabolism (the building up of tissues) and catabolism, the breaking down of tissues of the body, and it does so in response to conditions in the environment.

How to Stimulate mTOR for MAX Muscle Growth


In regards to muscle building specifically, mTOR regulates various steps of muscle development and pathways affecting hypertrophy (aka muscle growth).


Hypertrophy itself is impacted by mechanical stress on the muscle fibers, physical activity, availability of nutrients (protein and carbs, primarily), and growth factors.


To build bigger muscles, you ultimately need to be in a net positive protein balance, wherein your body is building more than its breaking down. Spend enough time in this net anabolic state and voila! You build muscle.


So, how do you stimulate the mTOR pathway, and ultimately ramp up muscle protein synthesis to build more muscle?


For starters, you need to perform resistance training, which has been shown to be a powerful stimulator of mTOR.[1]


But, stimulating mTOR (and as result muscle protein synthesis) isn’t enough to guarantee muscle growth. You also need to supply your body with the raw materials it needs to build and repair tissues -- protein, carbohydrates, and fats.


It just so happens that protein and amino acids (especially leucine) are also pretty potent mTOR stimulators in their own right. Insulin (the hormone responsible for shuttling nutrients into our cells) has also been shown to stimulate mTOR and protein synthesis.[2]


Put this all together and you’ve got the basics for a primetime muscle building lifestyle:


  • Perform resistance training (lift weights)
  • Consume enough protein and essential amino acids (like those found in ISOWHEY Max and EAminoMAX
  • Consume a higher carbohydrate diet which raises insulin levels (which not only boosts protein synthesis, but helps reduce muscle breakdown due to the anti catabolic properties of insulin


  1. Burd NA , Holwerda AM , Selby KC , West DW , Staples AW , Cain NE , Cashaback JG , Potvin JR , Baker SK , Phillips SM . Resistance exercise volume affects myofibrillar protein synthesis and anabolic signalling molecule phosphorylation in young men. J Physiol 588: 3119–3130, 2010.
  2. Vander Haar E, Lee SI, Bandhakavi S, Griffin TJ, Kim DH. Insulin signalling to mTOR mediated by the Akt/PKB substrate PRAS40. Nat Cell Biol. 2007 Mar;9(3):316-23. doi: 10.1038/ncb1547. Epub 2007 Feb 4. PMID: 17277771.

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