How Long Does It Take To Lose Muscle? (+ Tips For Avoiding)

how long does it take to lose muscle

Muscle loss is a real issue when it comes to dieting, inconsistent training schedules, and aging. 

Most of the muscle loss we are faced with is within our control and can be combated with a consistent workout program that focuses on weight training, proper diet, and having realistic goals during a weight loss diet.

Muscle loss can occur in as little as five days, with most muscle loss beginning between 5-14 days of inactivity. The rate of muscle loss can vary based on the individual, the amount of muscle they have to lose, diet, age, and sex.

If you are serious about not losing muscle during a weight loss phase or during periods where you may not be able to train as much, then this article is for you.

I’ll cover:

  • How Quickly Do You Lose Muscle
  • How to Tell If You’re Losing Muscle
  • How to Avoid Losing Muscle

How Long It Takes to Lose Muscle Mass

Muscle loss can occur in as little as five days of inactivity, however, a more typical range would be that muscle loss can begin between 5-14 days of inactivity.

While this may seem alarming (and it is), you can combat this by training at least 2-3 times per week with hard intensity, and tracking your workouts so that you can continually progress yourself and build muscle. 

If you take a few days off (or a week for vacation), be sure to get back into the gym as soon as possible to halt muscle loss and quickly rebuild and progress your training.

With the Fitbod app, you can build custom workouts based on your goals and gym access to maximize your muscle growth. The Fitbod app will ensure you progress your workouts every week to stimulate muscle growth and results.

4 Factors That Determine How Quickly You’ll Lose Muscle

factors that determine how quickly you’ll lose muscle

Below are four factors that can determine how quickly you’ll lose muscle. 

Note: Some of these can be alleviated by weight training 2-3 times a week (or more) on a consistent basis, eating enough protein, not living an inactive lifestyle, and not losing weight too rapidly.

Your Age

It’s no secret that as we age we lose muscle, however, if you are inactive and older, you will lose muscle much faster than a younger individual

Worse, you will have a tougher time regaining the muscle after you lose it. 

This is why it is so important to adopt weight training and be consistent over the course of your life, especially as you age, as the older you get, the quicker the odds are stacking up against you if you don’t work hard to maintain and grow muscle on a consistent basis.  

Your Sex

Research has shown that as we age, females tend to lose muscle slower than males (inactive individuals). 

While this may seem a win for females out there, the same study found that despite slower rates of muscle loss, males tend to still carry more muscle overall, which often results in females still seeing significant decreases in functional strength earlier or at the same rate as males. 

Note: There was a limitation in this study in that none of the subjects had weight trained before, which has been shown to help slow muscle loss as we age significantly, in both men and women.

The Amount of Muscle You Have to Begin With

Individuals who have a lot of muscle tissue starting out will notice quicker rates of muscle loss simply due to them having more to lose. 

They may notice things quicker also since they are used to carrying a lot of muscle and having the benefits of having more muscle (feeling stronger, leaner, etc). 

Individuals who do not have a lot of muscle will often lose muscle slower, simply because they were not very muscular to begin with and had less to lose. 

Less muscular individuals may find, however, that they will feel weaker and more impaired by their muscle loss sooner than more muscular individuals (similar to males vs females).

How Often You Weight Train

We know that muscle loss can happen as soon as 5 days of inactivity, which means that you need to train hard at least twice per week (each muscle group) to avoid losing muscle. 

This would be the bare minimum to avoid muscle loss and just maintain your muscle.

If you are dieting, you may need to train more than that as you are already losing weight (fat, muscle, and water weight) as a result of being in a calorie deficit. 

Stepping up your workouts during this phase can help you avoid muscle loss from undereating.

How Hard You Weight Train

When you are trying to build muscle, you need to train hard, and continually try to progress your workouts. 

When you are only trying to maintain muscle, and are not in a calorie deficit, you can get away with less intense training. 

If you are dieting though (in a calorie deficit) and want to avoid muscle loss, you need to not only train frequently but also train hard to make sure you do not lose muscle from inactivity.  

The body sees a caloric deficit as a way to lose both fat and muscle, so you need to train hard to preserve as much muscle as you can.

Your Protein Intake

The body needs protein, as it is what helps build muscle tissue, repair muscle, and helps signal the body to maintain muscle tissue. 

High levels of protein in the diet can help you build and maintain muscle, which makes protein intake key for muscle retention, both when dieting and not (more on my protein recommendations below). 


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How Can You Tell If You’re Losing Muscle?

how can you tell if you’re losing muscle

If you suspect you are losing muscle, you can use the below methods to help determine if you may be losing muscle. 

Take Body Measurements

If you want to track muscle loss/gain, you will need to do more than just step on a scale. Some of the best methods for doing this are having a DEXA scan or taking skinfold measurements. 

Both of these methods can be a reliable way to track the amount of muscle (or the changes in muscle tissue).

Other methods like bioelectrical impedance scales can be used too, however, these are often unreliable, so this may not be the best option (even though they are widely available). 

Another way to do this is to take circumference measurements (ie use a tape measure to measure various areas of your body), and analyze those measurements with your body weight and with pictures to make a hypothesis on whether or not you are losing muscle, or just losing fat.

Monitor Your Performance In Training

If you find you are getting weaker and not able to do the same weights and reps as in prior weeks, and/or your overall performance is slipping, this may be a good indicator of muscle loss. This rate of decline should be looked at over the course of 2-3 weeks, as sometimes we just have an off week.

The exception to this is when you are dieting and actively trying to lose weight. 

Ideally, you will not lose too much strength or performance, however, if you find you are losing weight, and losing performance (strength, power, fitness), then you may be dieting too aggressively or have been dieting for too long.

Monitor Your Rate of Total Weight Loss

When losing weight, you want to make sure you do so at a pace that helps you retain as much muscle as you can in the process. 

When losing weight, you want to aim to lose .5-1lbs per week for people who are generally lean, as anything faster than that may result in you losing weight (fat, water, and muscle tissue) too fast, and could result in higher proportions of muscle being lost. 

If you are someone who starts a diet and has higher levels of body fat, you may be able to aim for .75-1.5lbs of weight loss per week.

It is also important to remember that your rate of weight loss (weight on the scale) is slower the deeper you get into a diet, as you tend to have more fat and water weight to lose at the beginning of a diet than at the end. 

Look At Body Pictures

If you lose weight, you should be able to see more of the underlying muscle, and still have muscle size and tone. 

If you find that you are losing weight on the scale, but look generally the same (other than just being smaller in size, but no visible definition changes in the muscle) you may in fact be losing equal amounts of muscle and fat (not good). 

5 Tips to Avoid Losing Muscle

tips to avoid losing muscle

1. Lift Weights at Least 2-3 Times a Week

Lifting weights 2-3 times a week.  This is just a minimum.

2. Train a Muscle Group at Least Twice Per Week

You want to make sure to train a muscle at least twice per week, or every few days to avoid being inactive for too long. 

3. Eat Enough Protein

Catherine Gervacio, Registered Dietitian and nutrition writer for Living Fit , says to aim to consume .8-1g of protein per pound of bodyweight per day, with higher intakes being possible during periods of calorie restriction (dieting), up to 1.3g of protein per pound per day.

4. Do Not Lose Weight Too Rapidly

This is an issue with crash diets, as people tend to lose high amounts of muscle and fluids, with some fat loss, and then end their diet and are left with some fat loss, a lot of muscle loss, and a crashed metabolism. 

5. Supplement with Creatine (When Dieting)

Creatine has been known to be a helpful supplement for building muscle and improving performance in the gym, and it has also been studied to determine if it can help slow muscle loss in patients with wasting diseases. 


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Frequently Asked Questions

How Long Does it Take to Regain Muscle Mass?

Generally speaking, you can expect to regain muscle mass after a period of inactive at the same rate or similar rate as gaining muscle mass in general. This means that most people can aim to gain .5-1lb of muscle mass per week, whereas some more muscular individuals may find their rate is slightly slower.

Can Muscles Turn Into Fat?

No, muscle cells do not turn into fat cells. When you are inactive, you will lose muscle tissue, which is an independent process of fat loss or gain.

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About The Author

Mike Dewar

Mike holds a Master’s in Exercise Physiology and a Bachelor’s in Exercise Science. He’s a Certified Strength and Conditioning Specialist (CSCS), USA Weightlifting Advanced Coach, and has over 10+ years of experience working with collegiate athletes, national level lifters, and beginners alike. Mike is Founder of J2FIT Strength and Conditioning, a growing global training company with gyms in New York City, Cincinnati, and online offering personal training, online custom coaching programs.