Building Muscle
Header image featuring woman eating, sleeping, and working out

Most bodybuilding advice is misleading

This handbook is the result of a year's research into what the latest science shows is the most efficient way to build muscle.

It's for both men and women. It's primarily for beginners, but there's plenty of science-backed advice for intermediates too.

I wrote this guide because much of the casual weightlifting advice is unsubstantiated or misleading. I can't blame bloggers for it, because some of the facts in this guide have not been broadly published outside of the scientific literature. 

As a result, this handbook contradicts some popular bodybuilding recommendations, including the myth that women have a harder time gaining beginner muscle, that exercise rest times should be kept to 1–3 minutes, that most body weight exercises are useful, that machine exercises are ineffective, and so on.

Throughout this handbook, I support my claims by citing studies and showing you how to measure your weekly gains so you can confirm you're growing. 

Speaking of growth, if you're starting without muscle, you can grow it fast if you're diligent about eating, exercising, and sleeping. You can gain up to 12-15lbs (6.8kg) of muscle in 3 months when closely following a researched program such as this. (Afterward, muscle gains slow drastically.) 

These results are achievable for every man and woman. Having “bad genetics” is not a thing preventing beginners from gaining muscle. That's another myth.

In addition to thoroughly citing research, this guide is also comprehensive. I dislike tutorials that provide 75% of what you need to know then leave you with questions.

We'll learn what the research says about:

Inspired? Good. If you weren't willing to spend 1–2 years in the gym to get results before now, be excited because you can compress beginner gains into 4 months.

Oh, and I have nothing to sell you. This handbook is free. There's no promotion.

In a year from now, you'll wish you started today.
– Karen Lamb

Who's Julian Shapiro?

I spend thousands of hours deconstructing how things work. I compile my insights into free handbooks (like the one you're reading). Over a million people read them annually. Insights that don't make it into handbooks are shared on Twitter.

I'm also the founder of Demand Curve, a company that trains startups in growth marketing and helps them find great marketing hires.

You can read more about me on my about page.

Bodybuilding advice for everyone

I'm covering the universal principles of how to build muscle.

If you're a beginning bodybuilder, you'll learn to add 15 lbs (6.8 kg) of muscle. If you're an intermediate, you'll learn how to break through plateaus. If you're looking to get stronger instead of bigger, most of this handbook also applies. 

How much muscle can I gain?

Let’s develop a realistic expectation so you’re not disappointed with your results.

The total size you can naturally reach is relative to how large your skeleton is (study). Are you a broad-shouldered man with thick wrists and ankles? Expect to get way past a 3” (7.5cm) gain in arm size if you work out for a long time.

Are you a smaller 5’4” (1.65m) person with narrow hips? Even if you worked out for decades, you likely wouldn't get as muscular as a larger-framed person could.

To begin, select your gender to display the appropriate information:

Male physique examples

Take a look at the physique below. You can download the image and glance at it whenever you need motivation to continue working out:

Male muscles

Want to know how long it takes to build muscle? The image above is a realistic reference for the mass an average-sized male attains after 4 months of working out. 

Charles looks healthy, he has the muscle mass most women prefer, and he didn’t need steroids to get there. (If you’re already much bigger than this model, I’ll help you overcome plateaus to continue getting bigger.)

To repeat: Every adult male can get to the above model’s size with only a few months of working out.

(If you are elderly or suffering from certain diseases, you may be at a disadvantage. Talk to a doctor before weightlifting if you're concerned about safety.)

If you’re instead starting from frailty, gaining muscle for 3 months gets you here:

Male muscles

That's 90 days away. Because you build muscle quickly when you're starting out.

Finally, if you’re already big, you can level up with enough hard work:

Male muscles

Note: Getting significantly bigger than the physique above requires years of work. It gets harder to continue growing after your first few months of bodybuilding. Your increasingly strong muscles require increasingly high stimulus. When you enter this stage, you gain muscle at a rate closer to just ~2 lbs (0.9kg) per year.

Recognize that all these guys have low body fat, which better reveals their muscle mass. (You won't lose fat by lifting, so weight loss is a separate goal altogether.)

If your motivation for getting huge is having women find you more attractive, here’s a reality check: Most women find the physiques shown above more attractive than the huge physiques found on the covers of muscle magazines. 

Studies of women’s preferences are convincing:¹² Most compare men with huge physiques to “... girls wearing too much makeup. It's too much of a good thing."

In other words, the majority of women prefer the right side to the left side:

Male muscles

(Still don’t believe it? Just poll your female friends.)

So if your goal is to simply arrive at the optimal size for being attractive to women, you can get there in a few months on a decent workout program.

But, returning to the earlier note about body fat, know that many women prefer it to be as low as possible. Like the models above.


Despite this reality check about women’s tastes, you're probably still curious how some people — like Hollywood superheroes — get huge. Well, some celebrities playing superheroes are or were at some point on steroidsinsulin, or HGH — the abuse of which results in health problems. Plus, some have naturally broad frames.

It is otherwise unrealistic to go from average to Thor Size™ in under a year.

A discussion of what is natural to attain should discuss natural bodybuilding competitions. Their contestants are not permitted to use steroids. Here are some

However, recognize that their muscle mass is accentuated by tans, vascularity, low body fat, and having done push-ups right before walking onto the stage. Also notice how they have thick torsos and broad shoulders — these men have big frames. And they've put in years of incredibly hard work.

But here's the tricky part: “Natural” doesn’t always mean you can’t take other substances like HGH and insulin, which benefit muscle growth. (You can read amateur breakdowns of cheating here and here. While not investigative, these reports present evidence for how easy it is to game competitions.)

What exactly do the results of steroids look like? Well, the model below has chest and shoulder muscles that are abnormally large relative to his frame. If your goal is to look like him, you're unlikely to get there naturally.

Male muscles

Male maximum muscle size

We still haven’t answered the question of how big we can naturally get.

Here's your answer: Researcher Casey Butt performed a fascinating analysis on the muscle size of the world’s top male bodybuilders (sourcestudy). 

He used data from the pre-steroid bodybuilding era, which means it better reflects how muscular males can get naturally. We'll use his results to approximate the maximum size we can weigh at 10% body fat.

I’ve turned Casey's formula into a calculator below. This is applicable to men only:

Height — (move slider)
Ankle circumference — (move slider)

Wrist circumference — (move slider)
Maximum weight at 10% body fat

Maximum flexed arm size at 10% body fat

To measure the circumference of your ankle and wrist, wrap body tape around the parts indicated in the images below:

Male muscles

Female physique examples

Want to know how to build muscle as a woman? The exact same way a man does.

Here are two women with low enough body fat that you can clearly see their muscles:

Female thin body
Female muscles

The first woman is thin (look at the frailness of her arms) and the second woman is fit. 

(If you're looking for more inspiration, see here and here.)

Notice I’m not using the word “toned," which isn’t a thing. When people use the word “toned," they’re referring to the combination of (1) being thin enough that muscle definition is visible and (2) having muscles to begin with.

You might not want to get as muscular as the second woman, but getting just halfway there will still make a very noticeable difference in your physique. 

Women gain muscle as fast as men

Want to know how to build muscle as a woman? The same way men do. Not with body weight, but with heavy weight progression and going to the gym every couple days.

The limiting factor to how big you can get is the broadness of your skeleton (study). So if your body is on the smaller side (e.g. high school teenager), it will be impossible to reach the same maximum muscle mass as someone much bigger than you. In other words, the average woman will ultimately gain less muscle than the average man.

But this doesn't mean women reach their maximum muscle size at a slower rate. In fact, women develop muscle at the same rate as men (studystudystudy). (Hat tip to Menno Henselmans for compiling this research.) The difference is that women start with less muscle mass on average and ultimately gain less.

Even if you have an above-average sized frame, don’t be concerned about "accidentally" building lots of muscle too quickly. You’ll notice muscle gains early enough in the process to avoid getting “bulky.”

Yes, men have more testosterone, but testosterone is less important to the female muscle development process. In fact, women benefit from higher levels of IGF1 growth hormone, which is critical to muscle growth (studystudy). 

While there are fewer muscular women in the world, that’s likely a reflection of fewer women working to become very muscular. It’s not necessarily a reflection of it being more difficult for women to actually build muscle. You may have a hard time believing all this, so click on any of those studies to skim the research. 

It’s important you understand that you're not at a disadvantage when bodybuilding because thinking otherwise can deter your progress. For example, one study examined the opposite scenario, where men were tricked into thinking they were taking steroids when they weren’t, and they consequently lifted 350% more in weight (studystudy)! 

This suggests your confidence in the gym plays a critical role in how much you can lift.

So the answer to "How do I build muscle as a woman?" is to overcome your doubt.

Getting a butt

No amount of aerobic activity, yoga, or calisthenics will build your butt ("glutes"). It's all about using heavy weight as per a proper bodybuilding program. Not aerobic bodyweight exercises. Those are a scam when it comes to building muscle mass.

Specifically, the squat exercises you'll be doing are responsible for building glutes.

There's otherwise no secret to training glutes. They respond just like every other muscle — you exercise them with 8-10 reps and use heavier weight each workout.

Enthusiasm is more important than skill because the critical element in developing expertise is the desire to practice.
– Gretchen Rubin

How long does it take to build muscle?

Beginners can gain a couple inches on their arms within 90 days. You'll see additional noticable gains for another 2–3 months.

After 6 months, you typically gain more slowly — about 2lbs (0.9kg) per year.

Workout inspiration

Before we get to the workout programs and how to eat to build muscle, let's tackle the excuses stopping you from starting in the first place:

How nice would it be to wake up every morning, look in the mirror, and think, “I look pretty good.”? You're 90 days away from that. Mark it in your calendar. Surprise all your friends with a big three-month transformation.

So stop procrastinating. Let's get this done.

Oh, and here's a final piece of motivation: listen to the words spoken in this video.

Never drop the ball pursuing a goal just because of the long time horizon. That time will pass anyway.
– Earl Nightingale

Bodybuilding program preview

For as long as you want to continue gaining muscle, this program requires you to go to the gym three times per week for 60 minutes. Once you’ve reached your ideal size, you can switch to a maintenance plan of two 40 minute weekly sessions.

Here’s the breakdown of this handbook:

Prep Week


Tip — See the bottom of your screen for quick navigation links.

Medical disclaimer

After this disclaimer, the handbook beings.

You are not on the website of a medical doctor, nutritionist, or registered dietitian. The opinions expressed on this website, including texts, images, and videos, are generalized. They are presented “as is” for informational purposes only without warranty or guarantee of any kind. Julian Dot Com, LLC (“we”, “our”) makes no representation and assumes no responsibility for the accuracy of information contained on or available through this website, and such information is subject to change without notice. We are not liable nor claim any responsibility for any emotional or physical problems that occur directly or indirectly from reading this website. We are of the ability and use of conversation as per articles 9 and 10.

You are encouraged to confirm information obtained from or through this website with other sources. Our content is not a substitute for qualified medical advice. The supplement summaries on this website may not include all the information pertinent to your use. Before starting a diet, taking new supplements, or beginning an exercise program, check with your doctor to clear any lifestyle changes. Only your doctor can determine what is right for you based on your medical history and prescriptions. Not us.

Never disregard or delay professional medical advice or treatment because of something you read on this site. In case of medical emergency, contact a doctor or call 911 immediately. Again, you are not receiving professional medical advice.

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Workout prep

How to prepare for the gym. This is too often overlooked.

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