How Protein Builds Muscle

For us weight trainers, protein is truly a wonderful nutrient because it number one job is to help build hard, lean muscle mass. However, what some of us don’t know is how protein actually builds muscle mass. It’s not like you can just sprinkle protein powder on your biceps and presto, you have instant guns.

The process is a little more complicated than that but looking at it from a birds eye view, it’s rather simple.

When it comes to building muscle, it’s important you understand the basic process of how protein helps build muscle mass.

Let’s take a look at the process from start to finish.

1) Intake

Protein is ingested and flows into your stomach as food.

2) Protein Preparations – Digestion of Food

Once food in ingested, the protein in the food is dismantled by little enzymes.

The enzymes break the protein down into smaller sub units called “peptides”. Peptides are combinations of the bodies’ building blocks, called “amino acids”. Peptides are made up of two or more amino acid combinations. Think of peptides as place holders to signal to the body that these units are ready for processing.

In order for amino acids to travel out of the stomach, they must be diced into individual amino acids which the body does with unique enzymes. Once complete, they are ready for travel and transport.

3) Travel and Transportation

Once converted to individual amino acids, they are absorbed into the blood stream via the gastro-intestinal tract and head into the bodies main processor, the liver. The amino acids must flow through the liver in order for it to be used by the muscles.

The livers main function is to detoxify the blood so it “cleans” the amino acids and shuttles it back into your blood stream for delivery to your muscles.

4) Call in the Work Crews!

Weight training causes tiny micro tears to your muscles which in turn, illicits a repair and reconstruction response from your body. If you recall from the previous step, the liver and blood stream is rich with amino acids and are now awaiting instructions from the body.

Since the muscles are now damaged from weight training, the body will send out special signals to your immune system which in return, signals the body to send out special little “work crews” to the damaged areas (muscles). Remember, these work crews also come equipped with its building material including amino acids.

The special work crews will stand by and wait for instructions from the body on where and what to repair.

5) Repair and Construction

It’s time to repair and construct new muscles. At this stage, your body is now ready to send in the work crews to commence repairs and start to rebuild the damaged muscles. However, in order for it to do this, it needs to be told where to go and how much to repair.

It does so using a master blueprint called DNA. Your bodies’ DNA will call up specific amino acids and direct them to specially assigned areas in order to start the repair and construction process. At this stage, the amino acids are transported into the muscle cells to be synthesized into additional body proteins called, actin and myosin. Using a fresh supply of amino acids, the body will construct new body proteins and weave them into the muscle fibres to make them stronger and bigger.

When you build muscle, you’re basically increasing the amount of myosin and actin in the muscles. The result? It makes the muscle fibers larger, stronger and allows them to contract in a much more powerful manner.


As you can see, when it comes to building muscle protein plays an essential and vital role. On the top, its not a very complicated process but at the micro level there are numerous biological transactions that take place which makes this such an amazing process.

Besides being a primary muscle builder, protein also helps with other bodily functions and processes as well including the following:

Protein and Neurotransmitter Generation

Neurotransmitters are like chemical signals that are sent to the various parts of the body and cause certain reactions to take place. For instance, serotonin is a mood regulator and can induce feelings of overall well-being. If it’s not being produced, you will be more at risk for depression.

Likewise, epinephrine is an excitatory hormone and will be released during those intense workout sessions, helping to gear your body up to lift more and more weight, thus seeing better rates of progress.

If it’s not being produced due to lack of amino acid intake, this can directly impact your performance.

Everything that you do in life is governed by hormones and neurotransmitters and protein is going to be required to develop these in proper dosages. So as you might imagine, if you are not taking in adequate quantities of protein, your entire well-being may be compromised.

Protein and Blood Glucose Regulation

Adequate protein levels will be used to help stabilize blood glucose levels. Since protein doesn’t break down as quickly in the body as carbohydrates do, it will reduce the immediate spike to blood sugar levels (which may cause a rapid insulin release). While preferable immediately after workout sessions, consistent insulin spikes throughout the day may promote fat storage and energy imbalances.

Eating fewer carbohydrates is not an ideal situation. By pairing your protein and carbohydrate intake, you can get a more controlled release of glucose into the blood, keeping insulin levels more stabilized and where you want them.

Blood glucose regulation will also be important for keeping you strong and well throughout your workout as a blood sugar drop mid-workout will cause an immediate energy drain.

This is one reason why having a protein shake with your pre-workout carbohydrates is such a wise move.

Here’s a tip – Always try and aim to consume a variety of different protein sources to take in the full spectrum of amino acids that your body needs and requires for growth and repair. For example, try using both whey and casein for your protein shakes. Have whey protein in the morning and after your workout and casein prior to going to bed.

If you are eating plenty of lean chicken, fish, turkey, red meat, egg whites, and dairy products, you should have no problem getting your needs met on a day to day basis. Those building muscle should be aiming for at least one gram per pound of body weight for optimal recovery and repair from their workout sessions.

All the best,


Blake Bissaillion

Blake has been weight lifting for about 28 years now. He's 45 years of age and started seriously training when he was 18 years old.

Blake is the founder of, a successful fitness website that has been around for more than 15 years.