Training Hard But Not Seeing Muscle Growth? Here’s Why Protein Matters!

Written by Mackayla Brennan

Content writer and Nutrition student 

Mackayla Brennan is a health and nutrition content writer at Hercules Supplements. She focuses on creating evidence-based content on digestion, gut health and nutrition, helping everyday Australian's translate complex research into practical dietary advice.

Many individuals train consistently but still struggle to see meaningful muscle growth. Despite putting in hours at the gym, progress can feel slow or even non-existent.

One of the most common reasons for this lack of progress is insufficient protein intake. Protein plays a critical role in muscle repair and growth, and consuming the appropriate amount helps support the body’s ability to build lean muscle and recover properly from training. Without enough protein, even the most dedicated training routine may fail to produce the results you expect.

You’re Not Eating Enough Protein

Protein is made up of amino acids that act as building blocks for cells and tissues in the body. The human body relies on 20 different amino acids, but only part of this group can be synthesised internally.

The rest, called essential amino acids, must be obtained through the diet. When you consume protein, your body digests it into these amino acids. Once absorbed, they’re put to work in critical functions such as repairing tissues, supporting immune health, and even providing energy when needed.

Skeletal muscle, like other tissues, is in a constant state of turnover, breaking down and being rebuilt. To grow new muscle, your body must take in more protein than it loses to complete this process. This balance is often referred to as achieving a positive nitrogen balance, since protein is rich in nitrogen. Without sufficient protein intake, the body may be forced to break down existing muscle tissue to free up amino acids for vital processes. Over time, this can reduce strength and muscle mass and severe case can cause osteoporosis.

How Much Protein Do You Actually Need?

Research suggests that individuals interested in muscle growth should aim for a protein intake of 1.6 - 2.2 g/kg/d. For example, a 70 kg person would need between 112 g and 154 g of protein daily to fully support muscle building and recovery. Meeting this target consistently can be challenging through diet alone, which is why many people use high-quality protein supplements to help reach their daily intake goals.

Signs You’re Not Getting Enough Protein

It is important to understand the signs that your body is not getting enough protein.

You're training hard but your muscles are not responding 

Protein provides the amino acids required to support muscle protein synthesis, the process responsible for repairing and building new muscle tissue. When protein intake is inadequate, this process becomes less efficient, making it difficult for muscles to adapt and grow in response to training.

For many individuals, this is one of the earliest and most frustrating signs of insufficient protein intake.

You're constantly sore and have a slower recovery 

Skeletal muscle is in a constant state of turnover, breaking down and being rebuilt, especially after resistance training. This natural cycle of damage and repair is what allows muscles to grow stronger over time. Without adequate protein, this repair process becomes less efficient, which can contribute to prolonged soreness, slower recovery, and reduced training performance.

You feel tired even though you had a good quality sleep

Protein is a crucial energy source for the body and plays a role in physiological processes such as hormone regulation and enzyme production. When protein intake is too low an individual can feel weak and unusually exhausted even after a good quality sleep.

Ensuring adequate protein intake helps support energy levels and overall physical recovery

Where Most People Go Wrong

Here are a few common mistakes people do:

1. Skipping breakfast

2. Not tracking intake

3. Consuming low protein meals

Easy Fix

To avoid the signs of low protein intake, it is important to ensure you are consuming sufficient protein each day. Increasing your protein intake can support muscle repair, promote muscle growth, and contribute to healthy weight management.

Paying attention to the signs of inadequate protein intake can help you identify when dietary changes may be necessary. Addressing these signs early allows the body to recover more effectively from training and maintain optimal muscle function.

In many cases, meeting daily protein requirements through whole foods alone can be challenging, particularly for individuals with higher training demands. Adding a high-quality protein supplement like Hercules Supplements plant protein can be a convenient way to increase daily protein intake and support muscle recovery and growth.

Frequently Asked Questions

What happens if I do not consume enough protein?

Not consuming enough protein each day can contribute to fatigue, reduced recovery, increased hunger, and loss of muscle mass and strength over time. Protein plays an important role in muscle repair, immune function, and overall health, so consistently low intake can make it harder to maintain performance, body composition, and energy levels.

How much protein do I need?

The amount of protein you need depends on your body weight, training routine, and overall goals. For muscle growth, many people aim for around 1.6 to 2.2 grams of protein per kilogram of body weight each day. That means a 70 kg person may need between 112 and 154 grams of protein daily to support recovery and lean muscle growth.

What are the signs that I am not getting enough protein? 

It is important to recognise the signs that your body may not be getting enough protein. Common signs can include feeling constantly tired, struggling to recover properly, ongoing muscle soreness, and training hard without seeing the muscle response or progress you expect.

References 

Doherty, C. (2025) What Happens to Your Body When You Don’t Get Enough Protein. Verywell Health. https://www.verywellhealth.com/protein-deficiency-symptoms-11754340

Stokes, T., Hector, A., Morton, R., McGlory, C., & Phillips, S. (2018). Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training. Nutrients, 10(2), 180. https://www.mdpi.com/2072-6643/10/2/180/pdf

Wellbeing Nutrition. (2026, February 9). Signs You’re Not Getting Enough Protein to Build Muscle. Wellbeing Nutrition. https://wellbeingnutrition.com/blogs/sports-performance/10-signs-you-re-not-getting-enough-protein-to-build-muscle

What Is Nitrogen Balance? Journal Of Nutrition. (2023, September 13). Journal of Nutrition. https://journalofnutrition.org/encyclopedia/what-is-nitrogen-balance/