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

How to build muscle

I cover everything the science says about exercising and eating for building muscle. See the bottom of your screen to navigate this handbook's pages.

And scroll down for an important introduction to building muscle.

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Most bodybuilding advice is misleading

This handbook is the result of one year's research into what modern science proves is the most efficient way to build muscle. It's for both men and women.

I wrote this guide because — even in 2019 — much of the casual weightlifting advice is unsubstantiated and misleading. I can't blame bloggers for it, because many of the facts in this guide have not been broadly published outside of the scientific literature. 

This handbook contradicts much of the 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 less effective than barbell ones, 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, a beginning bodybuilder can build muscle fast: Expect ~20lbs (9kg) of muscle in 3 months when closely following a researched program like this. (After that, muscle gains slow down 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 being scientifically accurate, this guide is comprehensive. I dislike tutorials that provide 75% of what you need to know then leave you with questions. To make this handbook your complete reference for building muscle mass, I've spent a year fine-tuning it to include proven nutrition and workout plans.

We're about to learn what the research says regarding:

Inspired? Good. If before now you haven’t been willing to spend 1–2 years in the gym to get results, get excited because you can compress that into 3–4 months.

Bear with me, as I know this sounds like an infomercial. But you will be impressed with this handbook. If you're still skeptical after reading it, call me a fool on Twitter.

And I should mention: This handbook is free and there's no promotion. I have nothing to sell you.

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

Who's Julian Shapiro?

I spend hundreds of hours researching interesting topics. Then I write concise yet in-depth handbooks for free. There's more to it if you want to learn about me.

I'm also the founder of the growth marketing agency, Bell Curve. If you work for a startup, and want to become better at growth, check out our training program.

Bodybuilding advice for everyone

I'm covering the universal principles of how to build muscle. For men and women.

If you're a beginning bodybuilder, you'll learn how to add 20 lbs (9 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, 95% of this handbook applies to you. 

How much muscle can I gain?

Let’s develop a realistic expectation so you’re not disappointed when you complete this program, and so that you sustain motivation throughout your gradual muscle gains.

First, select your gender to display the appropriate content:

Male physique examples

Take a look at the physique below. 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 show you how to overcome plateaus to continue getting bigger.)

♖ To repeat: Every adult male can get to the above model’s size without steroids and 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 your safety.)

If you’re starting from frailty, building muscle for three months gets you here:

Male muscles

That's just 90 days away. You can build muscle very fast when you're starting out.

And, 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 exercising. 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 these guys have low body fat, which helps reveal their muscle mass. You will not actually 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 jacked physiques found on the covers of muscle magazines. 

Studies of women’s preferences are conclusive:¹² Women compare huge physiques to “a girl 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:

Male muscles

(Still don’t believe it? 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 on body fat, know that many women prefer it to be as low as possible.


Despite this reality check about women’s tastes, you're probably still curious how some people — like Hollywood superheroes — get huge. Well, most (if not all) celebrities playing superheroes are or were at some point on steroidsinsulin, or HGH — the use of which can result in serious health issues. 

It is otherwise impossible to go from average to Thor Size™ in just two years.

So get celebrities out of your head as physique targets. You've been lied to.

A discussion of what is natural to attain should discuss natural bodybuilding competition. 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 are outliers with big frames. And, certainly, they've put in years of incredibly hard work.

But here's the more insidious aspect: “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 herehere, and here. While not investigative, these reports present evidence for how easy it is to game competitions.)

All of this is to once again hammer in that you must throw out the physique targets beat into you by pop culture and local gym rats if you want to build naturally.

What exactly do the results of steroids look like? Well, the model below has chest and shoulder muscles that are unnaturally large relative to his bone size. This relative size is not possible without artificial help.

If your goal is to look like this or bigger, that's fine, but just know that you're not getting there naturally.

Male muscles

Male maximum muscle size

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

Check this out: 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 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 unflexed 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 a muscle is exercised, it responds by getting bigger. It can’t stay the same size and just get harder. So 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 an enormous difference in your physique. 

If you only want to be muscular in certain muscle groups, this program provides a workout plan for only building your arms (biceps and triceps), abs, butt (glutes), and hamstrings. Not sure what those are? Refer to the illustration below:

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 a reflection of fewer women working to become very muscular — due to societal expectations. It’s not 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?

Below are photos of me before working out then 90 days after. You can get much bigger than the 90 day mark by continuing the program for another 2–3 months. (After 5–6 months, however, you gain muscle at about ~2lbs or 0.9kg per year.)

My arms went from 11" (28cm) unflexed to 13.5"(34cm). Inspiring for just 90 days.

Author physique starting pointAuthor physique ending point

Workout inspiration

You know that cycle where you keep delaying a diet because you can’t stop saying to yourself, “Let me eat dessert tonight and I’ll officially start my diet tomorrow”? That cycle can happen with bodybuilding too.

Commit or don’t, but don’t lie to yourself.

Let's work through some of your potential concerns:

My favorite mind hack for gym motivation is only allowing myself to listen to my favorite bands and podcasts when I'm working out.

Don’t you want to finally be at a place where you 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.

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


Medical disclaimer

After this disclaimer, we finally begin with prep week.

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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