how long should you bulk for

How Long Should You Bulk For? Advice For Skinny Beginners

Are you currently bulking, but putting on more fat than you are muscle? Then this post is for you! Because today, I will be explaining how long you should bulk for as a skinny beginner.

Lean bulking for a minimum duration of 4 months and an optimal duration of 8-12+ months will maximise muscle gains and minimise fat gains. Additionally, it is recommended to end your bulk when you have reached 15-20% body fat.

As an ex-skinny guy, I am no stranger to the frustrations of bulking. I’m either not gaining weight, or I’m gaining too much fat!

What a nightmare!

That’s until lean bulking completely changed my approach to gaining muscle.

And that’s why today, I will be sharing my research and experience with you.

So let’s dive right in!

Be Cautious Of Generalised Bulking Recommendations

Do a quick browse on the internet, and you may come across some generalised recommendations to bulk for 3 to 4 months.

But you should take this figure with a very large pinch of salt.

In other words be cautious!

This is because lots of factors will determine how long you should bulk for.

These factors include:

  • Bulking goals- where some people want to pile on as much mass as physically possible (you can see how long it takes here), others want to stay relatively lean.
  • Bulking method- a dirty bulk will maximise muscle and fat gains, whilst a lean bulk will provide muscle gains with minimal fat gains (more on this later).
  • Personal discipline- the more disciplined you are in following a training and nutrition plan, the faster you will achieve your goals.
  • Training level- skinny newbies will gain muscle faster than seasoned trainees.

All 4 factors will determine how much muscle and fat you will gain during a bulk.

Therefore it’s hard to give an exact figure on how long you should bulk for. Rather, it all depends on a combination of all 4 of the factors described above.

Maintain Flexibility In Your Bulking Duration

From my experience, bulking timelines should be guidelines (at most). In other words, you should be flexible in your bulking approach.

What do I mean by this?

line graph showing how long you should bulk for depends on how long before you exceed 20% body fat

Rather than tracking your bulking duration, you should track your body fat % instead.

After all, most of skinny guys will be bulking with the aim of maximizing muscle gains and minimizing fat gains. Therefore, it makes sense to track your body fat % instead of tracking how long you have been bulking for right?

More on this later.

First, I want to explain in more detail the 4 factors governing fat and muscle gain during a bulk.

Goals Determine How Long You Should Bulk

Firstly, your goals will determine how long you should be bulking for.

If your goal is to gain as much muscle as possible (with no regard to fat gains), then it makes sense to bulk for a longer period of time.

However, if your goal is to gain muscle whilst staying lean, then a shorter bulk may make more sense.

how long you bulk for depends on your goals

From my research and experience, most skinny guys strive for the latter.

In other words, they want to get big and keep the fat at bay.

Therefore- as a skinny guy looking to get a bigger and leaner body- you should keep your bulk as short as is required to achieve your goal. This will allow you to make maximum muscle gains and minimum fat gains.

Bulking Method Determines How Long You Should Bulk

Secondly, your bulking method will also dictate how long you should bulk for.

There are two types of bulks- dirty and lean.

chart showing how long you bulk for depends on your bulking method

A dirty bulk is one which puts you in a major caloric surplus (over 20% above your maintenance calories). In theory, this will maximise your muscle gains, at the expense of increased fat gains.(1)

Therefore, it makes sense to keep a dirty bulk short (assuming you don’t want to gain a whole lot of excess fat).

In comparison, a lean bulk puts you in a minor caloric surplus (between 5-15% above your maintenance calories). In theory, this will keep your muscle gains and fat gains balanced.(2)

Therefore, a lean bulking method affords you more time to bulk. And more time to gain muscle!

Check out my article for more details on how to lean bulk!

Choose A Suitable Bulking Method

So which bulking method should you opt for as a skinny guy?

One important factor you need to consider is that your body can only put on so much muscle in a given duration of time.

bar chart showing lean bulking produces the best muscle gains relative to fat gains

In fact, this 2013 study showed that dirty bulking provides relatively little extra muscle gains compared to lean bulking. Furthermore, a dirty bulk results in much larger fat gains.

To put it simply- a lean bulk will allow you to bulk longer and return the most muscle gains with the least amount of fat gains.

And this is why I recommend you to lean bulk.

So how long should a lean bulk last?

Greg O’Galllagher from Kinobody recommends a lean bulking duration of 10 months.

I would recommend lean bulking for a minimum of 4 months, and an optimum of 8-12 months before cutting. I call this the prolonged lean bulk method. And doing so will allow your body time to build muscle whilst suppressing fat development.(3)

Personal Discipline Determines How Long You Should Bulk

Thirdly, your ability to stick to an effective training and nutrition plan will affect how long you should bulk.

The optimum training plan to gain muscle focuses on the big compound lifts. Additionally, you should aim to hit each muscle group in the body with 12 to 24 sets per week.

Check out my other article to learn more about the compound lifts!

Likewise, the optimum nutrition plan to gain muscle focuses on hitting a caloric surplus target. If you are opting for a lean bulk, then stay within a 5-15% surplus.

Additionally, you should also reach your macronutrient quota:

Macronutrient% Of Total CaloriesApproximate Grams Per DayReasonExamples
Protein35%1.5g per pound of lean body weightProtein is required to build muscle. If you under consume protein, your body will not build muscle.Lean red meat, poultry, fresh fish and shell fish, legumes, soy products.
Complex Carbohydrates35%2.5g per pound of body weightComplex carbs fuel your workouts. Aim to consume most of your carbs during the day (especially pre and post-workouts).Potatoes, whole grain pasta/bread, legumes.
Healthy Fats20%0.4g per pound of body weightHealthy fats also fuel your workouts. But they are also required for hormone production and muscle growth.Oily fish, nuts, seeds, vegetable oils, avocados.
Fibre10%6 portions of fruit and vegDietary fibre will slow down your digestion. This allows your body to absorb the maximum amount of nutrients from your meal.Fresh fruit and veg

Remain Disciplined To Reduce The Time Required To Reach Your Goal

If you are able to consistently stick to your training and nutrition plan, you will be able to reduce the time required to hit your goals.

Put it this way- you could be bulking for 10 months. But if you aren’t training hard enough or eating enough, then you will have to bulk for longer.

Conversely- if you are regularly over eating, then your lean bulk could turn into a dirty bulk. As a result, you will gain more fat than expected. And this would cause you to prematurely end your bulk in favour of a cut.

Prematurely ending your bulk this way comes with a major drawback- you will not achieve your highest muscle gain potential. And this means that your subsequent cut could eat away at the miniscule muscle gains you made during your short bulk.

Therefore as a skinny dude, it’s important to keep disciplined in your bulking plan. Stick to your 5-15% daily caloric surplus and macronutrient quota. This will allow you to stay on target for a 8-12 month lean bulk.

Current Training Level Will Affect Rate Of Bulking Returns

Lastly, your current training level will affect the rate at which you gain muscle. And this will indirectly affect how long you bulk for.

Let me explain by using the Lyle McDonald Model for muscle gains (see below).(4)

lyle mcdonald line model for yearly bulking gains

As you can see, a seasoned weight lifter will gain muscle at a relatively slow rate (2 to 6lb per year).

This is because their muscles are highly adapted to resistance training. And this means they require a much stronger stimulus to promote muscle growth.(5)

In contrast, a skinny beginner will gain muscle at a rapid rate (up to 25lb per year). And this is commonly referred to as newbie gains.(6)

The newbie gains phenomenon occurs because your muscles are not yet adapted to resistance training. As a result, they are highly sensitive to growth when you begin training.

Check out my other article for tips to build muscle fast!

Therefore- as a skinny beginner- you can lean bulk for longer than my previously recommended 8-12 month period . In fact, I would recommend you to do so if possible. Because this will allow you to really take advantage of your honeymoon period of newbie gains! Just keep an eye on your body fat %.

So how do you know when to stop your bulk? What body fat % should you stop bulking?

Tracking Body Fat % Is The Best Way To Decide Bulking Endpoint

As I have already mentioned, tracking your body fat % is the best best way to decide when to end your bulk.

In fact, this is a much better way to decide how long to bulk for (compared to judgment by timescale).

In other words- you should decide on a bulking endpoint based on reaching a specified body fat % rather than a specified time duration.

And this is because of the 4 variables I described previously.

aim to stop a bulk at 15-20% body fat

So how much body fat % should you reach before you end your bulk?

It is generally recommended to end a bulking period at the 15-20% body fat window.(7)

That’s because the 15-20% body fat window is the point where your muscle definition becomes hidden by fat.

Therefore- if you are a skinny guy- aim to bulk for the recommended 8-12 month period. But by all means continue bulking until you have reached the 15-20% body fat window. At this point you can end your bulk. This will allow you to develop defined musculature whilst keeping the fat away.

How To Track Body Fat %

An easy and convenient way to track you body fat % is to use body fat charts.

This body fat chart by Beyond The Box is my favourite.

The pictures are clear, and they provide an accurate representation of what each body fat % looks like.

As you can see, you can expect muscle definition to disappear at around 15-20% body fat.

And as I explained above, this is the ideal point to stop bulking and start cutting.

How Much Weight Should You Be Gaining Per Week On A Lean Bulk?

Now you may be asking:

So how much weight should I be gaining every week to ensure I am lean bulking correctly?

Most Skinny Guys

As I mentioned previously, it can be easy to accidentally over eat and enter a dirty bulk. It is also equally easy to do the opposite (under eat and prevent muscle gains from happening).

Therefore, you will need a reliable way to track your lean bulking progress.

Don’t worry, I got you covered!

table to show weekly target weight gain during bulking

Copy and paste the code below to share this image on your site!

This 2019 review advises that a skinny beginner should aim to gain between 0.25-0.5% of current body weight per week. Aiming for this target will maximise lean muscle mass gains whilst minimising fat gains.

To make things easier for you, I have visualised this on the chart above.

Simply find your body weight, and determine how much weight you should be gaining every week during a properly done lean bulk!

If we take a 130 pound skinny guy as an example- he would aim to increase his weight by 0.33 to 0.65 pounds every week!

Taking everything into consideration, you should aim to increase your body weight 0.25%-0.5% per week until you have reached 15-20% body fat. At this point, you can end your lean bulking and begin your cut! And this will prevent you from gaining too much fat!


Thats it!

Today I have explained how long you should bulk for as a skinny beginner.

Instead of following general bulking guidelines of 3-4 months, you should instead lean bulk for a minimum of 4 months and ideally 8-12 months. When done properly, this will lead to a 0.25-0.5% body weight increase per week.

If after 12 months, you are still under 15-20% body fat, you can prolong the bulk. Similarly, when you approach 20+% body fat, you know to stop bulking.

This method will allow you to prolong your bulking, and thereby give your body time to build muscle. At the same time, this method will also limit the storage of excess fat.

Will you be giving the prolonged lean bulk method a go?

Please let me know in the comments below! I know it can be hard to bulk without gaining fat as a beginner. But it really shouldn’t have to be!

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Thanks for reading guys!

Peace Out,


(Biochemistry BSc, Biomedical Sciences MSc, Ex-Skinny Guy)

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