Illustration of a skinny man building muscle.

The Skinny Guy’s Guide to Newbie Gains

If you’re a skinny guy who’s new to lifting weights, it’s possible to build muscle incredibly quickly. Lifters call this phenomenon “newbie gains,” and it lasts for about a year.

During that first year alone, the average man will often claim to gain around 20 pounds of muscle. Skinny guys often claim to be able to do even better, gaining upwards of 40 pounds in just a single year. Can beginners really build muscle that quickly?

However, although newbie gains seem to allow some beginners to build muscle unbelievably quickly, research shows that other lifters fail to gain any muscle when they first start working out. When that happens, they’re dubbed non-responders. Do non-responders really exist? And if they do, how do you know if you’re a non-responder?

Why are some guys able to build a lifetime of muscle in a single year, whereas other guys spend an entire lifetime unable to build a single year’s worth of muscle?

Illustration of a skinny guy building muscle and becoming muscular (before/after).

How Quickly Can a Skinny Beginner Gain Muscle?

During my first five weeks of bulking, I gained twelve pounds. My roommate gained 22. But then, after posting our results online, we discovered that what we’d just done was considered scientifically impossible.

The skeptics had a point. That rate of muscle growth is virtually unheard of, even for beginners making newbie gains. For example, here’s a quote from Vice Magazine’s article about how quickly beginners can build muscle:

How fast can you gain muscle naturally? If all the muscle-building stars are aligned—you’re new to lifting weights, eating enough food, lifting weights 4-5 times a week, and in your twenties with a relatively low-stress lifestyle—the average guy can hope to gain around eight or nine pounds of muscle after three months of hard training.

There’s a small mistake there. A single full-body workout will usually stimulate 48–72 hours of muscle growth in a beginner (study). That means that there’s no need for a beginner to work out more than three times per week. In fact, given how sensitive beginners are to muscle damage, extra workouts may slow down muscle growth. It’s only advanced lifters who benefit from training 4–5 times per week (study, study).

But that’s beside the point. Their claim is that a newbie would be lucky to gain 8–9 pounds of muscle during their first three months of lifting. If we look at the research, that’s not quite the case:

  • This study on beginners found that guys were able to gain 9 pounds of muscle during their first 8 weeks of working out.
  • In this study, a group of untrained beginners were able to gain an average of 12 pounds of muscle during their first 10 weeks of working out.
  • In another study, beginners were able to gain 15 pounds of muscle during their first 12 weeks of lifting weights.

The average beginner in these studies is gaining more than a pound of lean mass per week for several months in a row. This clearly shows that it’s not only possible to gain muscle at an extremely rapid rate, but that by implementing certain training and dietary interventions, we can reliably produce these rapid rates of muscle growth in the average beginner.

On that note, these rates of muscle growth are the average of all the participants. We’re not looking at case studies of people who were able to gain muscle quickly, we’re just taking a random sampling and looking at the average rates of muscle growth.

If the stars were aligned for a particular person, we’d expect them to gain muscle even more quickly than that. After all, even if their circumstances are the same, genetics must play a role in how quickly a beginner can build muscle, right? To see whether that assumption is true, we can look at the research on how rates of muscle growth vary between individuals. For example, this study found that:

  • The average beginner was able to add 2 inches to their biceps in 12 weeks
  • Some beginners were able to add up to 5 inches to their biceps in 12 weeks
  • Other guys lost muscle, despite following the exact same workout routine

There are a couple of interesting things about this study. First, it shows that some beginners can gain muscle almost three times as quickly as others. Second, it shows the phenomenon of “non-responders.” Some beginners don’t gain any muscle whatsoever when they start lifting weights.

Now, if you’re like me, you might assume that as naturally skinny “hardgainers” or “ectomorphs,” we have poor muscle-building genetics, right? After all, the term hardgainer makes it sound like we should have a hard time building muscle, right? But that’s not the case. Hardgainers have a hard time gaining weight, not a hard building muscle.

This is where things get interesting:

  • Skinny guys can build muscle more quickly than the average person. Our bones can only support a certain amount of muscle, and as we get closer to that limit, our rate of muscle growth slows. That means that the less muscle we have on our bones, the more quickly we can fill our frames out. Because we’re starting out less muscular, we can build muscle more quickly.
  • The “non-responders” in these studies don’t necessarily have bad muscle-building genetics. The rate that we build muscle is limited by the rate that we’re gaining weight. After all, if we aren’t eating enough calories to gain weight, how can we expect to gain muscle? That’s even more true if we’re already lean. For instance, the only way to go from 130 pounds up to 150 pounds is to gain weight, and so if we aren’t gaining weight, we won’t build muscle. This can create the illusion that we have poor muscle-building genetics when in fact we’re merely struggling to gain weight in general.
  • Non-responders aren’t necessarily skinny. As a skinny guy who was having trouble building muscle, whenever I would hear the term “non-responder,” I’d assume that they were talking about skinny guys like me. But that’s not the case. A lot of the non-responders in these studies are guys who gain fat instead of muscle when gaining weight. As a result, non-responders are more likely to be skinny-fat guys. These aren’t the guys who have trouble gaining weight, they’re the guys who have trouble with nutrient partitioning. (And there are solutions for that, too.)
Illustration showing a skinny hardgainer rapidly building muscle.

The first reason that I was able to gain twelve pounds during my first month of lifting weights wasn’t that I had exceptional muscle-building genetics, it’s because I was skinny. When I first started lifting weights, I had a BMI of 16.7. I was clinically underweight, and my doctor was urging me to bulk up for the health benefits. My roommate was in the same situation, with his doctor prescribing him pain medication for various weakness-related issues, such as tendonitis.

When we started hypertrophy training, eating a big bulking diet, and improving our sleep, our bodies exploded into growth. We were so underweight that our bodies were desperate for that extra muscle mass. Our newbie gains were so dramatic because our lanky frames still had so much room for muscle growth.

David Epstein, the author of The Sports Gene, found that each pound of bone can support five pounds of muscle. So if right now you’re shaped more by your bone structure than your muscle mass, you’ve still got plenty of room for muscle growth, allowing you to have more extreme newbie gains.

The second reason that I was able to gain muscle so quickly was that I was eating a good bulking diet. I was making sure to eat enough protein, I was getting most of my extra calories from carbohydrates, and I was eating close to a thousand extra calories every single day (which may have been overkill). I wasn’t just in a calorie surplus, I was in a huge calorie surplus.

The third reason, of course, was that I was following a good workout program. The quality of our workout program (and how consistently we follow it) has a huge impact on how quickly we can build muscle. Most studies that produce great newbie gains put beginners on a great workout program and then force the participants to follow it with perfect consistency.

There’s an important caveat to mention here. The studies that succeed in getting these insane rates of muscle growth aren’t the ones using generic fitness routines or strength training programs, they’re the ones where the participants are put on programs designed to stimulate maximal amounts of muscle growth—hypertrophy training routines.

Within four months, I’d gained over twenty pounds of muscle while losing a significant amount of fat:

The science of newbie gains, and how quickly a beginner can gain muscle when they first start lifting weights

I wasn’t even a total beginner during this transformation. I’d already gained twenty pounds, going from 130 up to 150 pounds. This set of progress photos was from the middle of my transformation, showing me going from 150 up to 170 pounds.

Here’s the entirety of my newbie gains, showing 55 pounds of drug-free muscle growth over the course of a couple of years:

Newbie Gains Explained: How quickly can a beginner build muscle when he starts working out?

Now, a common objection that people make when guys claim to gain muscle this quickly is that it’s not all muscle. They argue that a huge proportion of the weight gain is fat or other tissue. In my case, I got a DEXA scan showing that I had a body-fat percentage of 10.8%, which seems to be even lower than when I started:

When someone gains weight quickly, is it muscle or fat?

However, it is true that not all of our lean gains are muscle. If we’re speaking totally accurately, we’d be talking about gains in “fat-free mass” rather than gains in muscle mass. Our organs can grow, our skin needs to cover a greater area, our bones grow denser, and a bunch of other great things. It’s true that it’s not all muscle, even if it looks that way.

The next thing to keep in mind is that newbie gains aren’t linear. Rather, as we build more muscle, our rate of muscle growth gradually slows. The closer we get towards your genetic potential, the more our growth will slow. So when people talk about how it’s unrealistic to gain muscle this quickly, they’re mostly right. During most periods of our training, this isn’t possible. It’s only possible when we’re beginners, when we’re far away from our genetic potential, or when we’re recovering lost muscle mass after a period of weight loss or detraining.

But if you’re a skinny guy who’s desperate to build muscle, none of that matters. Because skinny guys are starting so far away from their potential, their newbie gains are more dramatic and last quite a bit longer. We are able to go through a rapid period of growth.

For an example of how this works, let’s compare ourselves against the average man. The average man starts off with roughly eighty pounds of muscle on his frame. If we imagine a skinny guy who’s starting with just forty pounds of muscle on his frame—which isn’t uncommon for skinny guys—then he’s essentially starting off behind the starting line, and so his newbie gains will look more like this:

Regardless of where you’re starting, though, your first workout will produce the most muscle growth, your second workout will produce slightly less, and so on. By the time you get to your hundredth workout, you’ll be gaining muscle at a noticeably slower rate. Your newbie gains will have gradually run dry. (Mind you, this assumes that you’re actually building a little bit of muscle every week. If you aren’t making any progress, then you aren’t “using up” your newbie gains, you’re just spinning your weight plates. We only “use up” our newbie gains as we inch closer to our genetic muscular potential.)

Because the rate of muscle growth slows even in the midst of our newbie gains, we can divide newbie gains up into two stages:

  • Early-stage newbie gains (months 0–3): the average newbie can expect to gain up to 15 pounds of muscle within their first three months of working out, but if you’re a naturally skinny, you can expect to gain even more. We often see skinny guys gaining upwards of 20 pounds within three months. Sometimes more.
  • Late-stage newbie gains (months 3–12): as you become more muscular, you’ll start to gain muscle more slowly. It might take another 6–9 months to double that initial amount of muscle mass that you gained. For the average guy, that might bring his newbie gains to 20–25 pounds within his first year of lifting weights. For a skinny guy, that would bring his newbie gains to upwards of 40 pounds within his first year.

Just to reiterate, though, all of this depends on how skinny you are right now. If you’re only a little bit more skinny than average, then your newbie gains will be more like the average man’s. If you’re like me, though, where you’re starting off quite underweight and under-muscled, then you can expect to build muscle far more quickly.

Also keep in mind that these rapid rates of muscle growth assume that right from your very first workout, you’re following a near-perfect bulking program. In real life, it’s rare for a beginner to know how to bulk. It usually takes a lifter a few years to get his newbie gains as he gradually learns how to train, eat, and adjust his lifestyle for muscle growth. In fact, some guys spend entire lifetimes weight training without getting their newbie gains. They still have an incredible potential for rapid muscle growth, they just never figure out how to do it.

For instance, if we look at something like sleep, we see that simply learning how to improve our sleep can speed up our rate of muscle growth by 30%:

Graph showing faster muscle growth with sleep optimization.

It’s also fairly common to go through a period of accidentally gaining too much fat—dreamer bulking—which can mean spending a couple of months trimming off that extra fat. I’ve certainly gone through that phase. That can be frustrating in a different way. If you do enough things incorrectly, you can wind up gaining too much fat while bulking, losing too much muscle while cutting, and getting stuck in skinny-fat purgatory, where you never figure out how to become lean and muscular.

Again, if we look at something like sleep, we see that it can have a huge impact on the rate of muscle-to-fat gain. Look at these differences in fat gain simply from differences in sleep optimization:

Graph showing fat loss from improved sleep.

You can imagine how the quality of someone’s training program could have a massive impact on their rate of muscle growth, especially since hypertrophy training combines together so many different factors: which lifts we do, how we do those lifts, how long we rest between sets, how many sets we do, how often we train each muscle group, and so on.

So this idea of quickly and leanly building muscle hinges upon proper hypertrophy training, eating a good bulking diet, and making the proper lifestyle adjustments, and a beginner who’s trying to put these pieces together by themselves probably won’t do a very good job. And that’s okay. Most of them improve over time. But you can see how the rapid rates of muscle growth we see in the research don’t necessarily apply to the average person putting together their own bulking routine.

Newbie gains explained: how much muscle can a skinny beginning gain in a year

But if you’re starting out skinny and you jump right into a professionally programmed bulking routine that teaches you how to do proper hypertrophy training, how to eat a good bulking diet, and how to make the right lifestyle changes (such as our bulking program), then it’s realistic to gain a full forty pounds during your first year of bulking.

Can You Still Make Newbie Gains?

One of the most common questions we get asked is about whether people can still make newbie gains. Oftentimes, people are worried that by training inefficiently in the gym, they’ve used up their newbie gains without building very much muscle.

Fortunately, that’s not how it works. Newbie gains have nothing to do with how many times you’ve tried to build muscle, they only have to do with how much muscle you’ve actually built. So if you’re training inefficiently or failing to eat enough calories or protein, you can stay a newbie for several years—even an entire lifetime.

The reason I say “fortunately” is that you can’t “use up” your newbie gains that way. They’ll be waiting for you when you start training and dieting properly for muscle growth. No need to worry about not having gotten off to a strong start.

Before I succeed at gaining my first twenty pounds, I had tried and failed to build muscle six times. That was irrelevant to my newbie gains, though, because failing to build muscle wasn’t bringing me any closer to my muscle-building potential. When I finally started bulking properly, all of a sudden I started building muscle quite quickly.

If you aren’t muscular yet, you can still make newbie gains. To understand why newbie gains work this way, we need to look at what’s going on inside our muscle fibres.

Why Do We Get Newbie Gains?

If you haven’t gotten your newbie gains yet, your muscle fibres are thin and only have a few nuclei in them. Even though your muscle fibres only have a few nuclei in them, though, that’s already quite remarkable. Most cells in our bodies have just one nucleus, which puts a strict limit on how big they can get.

Muscle fibre diagram for newbie gains

To understand how these special “myonuclei” work, the researcher Greg Nuckols uses the analogy of a wifi router. The wifi router can project an internet signal a certain distance. Once you get too far from the signal, your device can no longer connect. Myonuclei function the same way. Each one can only handle an area so big. That area is called the maximum myonuclear domain.

Our muscle fibres are made to adapt, though. These extra nuclei allow our muscles to grow quickly based on short-term needs, and then in the longer term, we can add nuclei to our muscle fibres, allowing us to build even more muscle. That means that building muscle, at least as a newbie, comes down to:

  • Filling out your nuclear domains with muscle.
  • Adding new nuclei to expand your domain.

Now comes the question, how do we fill out our nuclear domains and add new nuclei? Our muscles get a growth stimulus when we lift things. We can get this growth stimulus from carrying groceries, carrying around boxes at work, running up flights of stairs, and from certain types of physical activity, such as gymnastics and wrestling.

However, if we’re trying to build muscle quickly and efficiently, we can stimulate muscle growth much more effectively with resistance training, which ranges from bodyweight training to resistance bands to weight training, all of which are designed to cause muscular adaptations. Of these types of training, weight training generally makes it easier to build muscle, but all can work.

Even within the realm of resistance training, though, there are several different ways of training. The style that’s designed to stimulate a maximal amount of muscle growth is called hypertrophy training. (“Muscle hypertrophy” simply means muscle growth.)

Illustration showing a man doing a snatch.
Olympic Weightlifting.

Hypertrophy training is its own style of training. It’s different from strength training, such as Starting Strength and Stronglifts 5×5, which are designed to help us contract our muscle fibres more forcefully. It’s also different from power training, such as Olympic weightlifting and CrossFit, which are designed to teach us how to contract our muscle fibres more explosively. Now, to be clear, these different styles of weight training do stimulate muscle growth, just not as much growth as hypertrophy training.

Illustration of a geared powerlifter doing a barbell back squat in a squat suit and knee wraps.

With hypertrophy training, we’re not only trying to make our muscle fibres stronger (by adding contractile tissue), but we’re also trying to increase their work capacity (by adding sarcoplasm). So with Olympic weightlifting, we might do sets of three quick and explosive reps. With strength training, we might do sets of five reps, slowly grinding through the sticking point on the final reps. With hypertrophy training, we often spend most of our time doing sets of 6–20 reps. There are two reasons for this:

  • The more repetitions we do per set, the more overall weight we lift. For instance, if we do five reps with 225 pounds, that’s 1250 pounds lifted. Someone who can do five reps with 225 pounds is typically able to lift 175 pounds for twelve reps, which is 2100 pounds lifted. That’s 68% more weight being lifted. A systematic review of the research found that this appears to increase the amount of muscle growth we stimulate per set, perhaps simply due to greater amounts of overall mechanical tension.
  • The more overall weight we need to lift without rest, the more fuel our muscles need to store. Our muscles aren’t just made up of contractile tissue, they’re also made up of sarcoplasm—fuel. When we lift in moderate rep ranges, our muscles adapt by storing more of this fuel, which is often referred to as sarcoplasmic hypertrophy. This gives our muscles greater strength endurance and makes them much bigger.

For an example of how rep ranges can affect muscle growth, a study by Brad Schoenfeld, PhD, found that doing 2–4 reps per set increased quad muscle size by 4% over ten weeks, which is great. But doing 8–12 reps increased quad size by 10% over that same ten-week period. By lifting in the proper rep range for hypertrophy, muscle growth was more than doubled.

Graph showing varying rates of muscle growth.

With hypertrophy training, we’re also choosing lifts that are designed to stimulate muscle growth throughout our bodies. We’re favouring larger ranges of motion, keeping constant tension on our muscles, and challenging them in a stretched position.

Graph showing the difference in muscle growth when training with long and short muscles lengths.

For an example of why that matters, a meta-analysis found that challenging our muscles in a stretched position stimulates nearly three times as much muscle growth as challenging our muscles in a contracted position.

Graph showing triceps muscle growth from the bench press and triceps extensions.

For a final example, if we look at triceps growth, we see that we can build twice as much muscle mass by doing triceps extensions after the bench press as we would with just the bench press alone. (This is because the long head of the triceps crosses the shoulder joint and thus doesn’t activate very well in pressing movements.) With a smart combination of exercises, again, we can radically increase our rate of muscle growth.

So different styles of weight training favour different lifts, different rep ranges, different lifting tempos, and different training volumes, all designed to yield different adaptations. And so when we’re min-maxing every factor to stimulate faster rates of muscle growth, we can build muscle at an impressive pace, especially as skinny beginners.

Okay, so this explains a little bit about what’s going on inside our muscle fibres, why different styles of training provoke stimulate amounts of growth, and why a good hypertrophy training program can be so powerful. But why does our rate of muscle growth start off so fast and then slow down over time?

Early-Stage Newbie Gains: Claiming Your Domain

When you first start bulking, your muscle fibres quickly expand to the limit of their nuclear domains, as shown below. You can expect your muscle fibres to grow 15–27% before hitting that limit (study).

Newbie gains science diagram

Going back to the analogy of the wifi router, you can build muscle within your current wifi range without needing to make any real structural changes. Since beginners aren’t near the end of their range yet, this makes the first phase of building muscle quite quick and easy. In fact, this early stage of newbie gains is so quick and explosive that it’s described as steroid-like growth. 

This stage will last until you’ve maximized your nuclear domains. At that point, if your muscle fibres were to grow any bigger, your nuclei would lose control of them, and so your body halts muscle growth until it can install new wifi routers—add new nuclei. As you can imagine, it’s common for people to hit a plateau at this point.

This first plateau can be confusing. The methods that helped you gain your first ten or twenty pounds might not be enough to stimulate further muscle growth. For example, if I want to use wifi from the balcony, I can sit right next to the door and get a signal. Working from there is no problem. But if I want to work from the far side of my balcony, well, there’s no signal there. I’d need to go to the store and get a new router, which is a bit of a pain. Nothing has forced me to go through that effort, and so I haven’t ever bothered.

This same sort of thing happens with muscle growth. Your body doesn’t want to go through the effort of adding new nuclei to your muscle fibres unless you give it a strong enough incentive. That’s why the quality of our workout programs, how much effort we exert when training, and how consistent we are becomes ever more important as we continue building muscle.

But let’s say your workout routine and diet are good enough to stimulate more muscle growth. At that point, you’ll start making a new kind of adaptation: adding new nuclei to your muscle fibres.

Late-Stage Newbie Gains: Expanding Your Domain

Once you’ve reached the edge of your wifi range, the low-hanging fruits are gone, and it’s time to install new routers so that we can build your muscles even bigger.

Now, if you’ve been following good hypertrophy routine, your body will have been doing this all along. These processes can blend together. Right from your first workout, you’ll begin adding new nuclei to your muscle fibres (study). However, during the early stage of newbie gains, since all of your domains weren’t maximized yet, there was almost no limit to how quickly you could build muscle. You were adding new nuclei, yes, but you weren’t being limited by them yet.

Now that you’ve maximized those domains, from this point forward, every pound of muscle you gain will need to be preceded by gaining new nuclei:

Newbie gains science diagram

You add new nuclei to your muscle fibres by growing satellite cells and then fusing them into your muscle fibres. When your muscle fibre consumes a satellite cell, it gains that satellite cell’s nuclei. Muscle growth via cannibalism, but in a wonderful way.

This allows for even more muscle growth, and this is where most of your overall muscle growth will come from. At first, this growth can be quite quick. This is the stage of newbie gains is where guys gain another 10–20 pounds of muscle over the course of another few months.

And this is where the magic happens. The growth isn’t quite as quick, no, but the changes in your body are far more exciting. By adding new nuclei to your muscle fibres, you’re improving your ability to turn protein into muscle, you’re improving your insulin sensitivity, and you’re improving your ability to clear sugar from our blood, making you naturally leaner and more muscular. Best of all, these changes are permanent. You’re essentially improving your genetics.

You aren’t just carrying your computer to the limit of your wifi signal anymore, you’re installing new routers (that last forever) and expanding your domain. This allows you to make your muscle fibres much bigger (study).

This is when building muscle really starts to have a profound impact on our long-term health and appearance. This is how you build a strong and healthy body that lasts.

The End of Newbie Gains: Growing Tougher

As you push deeper into building muscle, you’ll start to notice that your muscles are adapting in two separate ways:

  1. Lifting makes your muscles grow bigger: This first adaptation is the one we all know and love. After a good workout, your muscles will rebuild themselves bigger so that next time, they are strong enough.
  2. Lifting makes your muscles grow tougher: This new, second adaptation is more nuanced. After a good workout, your muscles will rebuild themselves in a more durable way so that they won’t be as easily damaged next time. This is called the repeated bout effect (RBE).

The first adaptation is what newbie gains are all about: we build bigger, stronger muscles. The second adaptation is the opposite of that: our muscles grow more resilient, harder to stimulate, and more resistant to growth. You’ll notice this happening, too. As a beginner, it’s common to be brutally sore for a full week after a hard workout. During that time, your muscles will be so inflamed that you’ll feel like a cripple. After a year of lifting, though, you’ll be lifting twice as much weight, doing far more sets, pushing closer to failure, and yet your workouts will barely even make you sore. At best, you might feel a massage-like soreness deep within your muscles. It’s not the same as the soreness that prevented you from getting out of bed in the morning.

Growing tougher is technically a good thing. Your muscles are gaining the ability to do more work without sustaining as much damage. You can carry heavier things for greater distances and wake up feeling fresh the next day. Without a doubt, this is an upgrade to your body and your health. You are no longer fragile. However, if your goal is to continue building muscle, this can be a big problem. Your body is (literally) making itself immune to your workouts.

You’ve gone from gaining over a pound per week (early-stage newbie gains) to gaining around a pound per week (late-stage newbie gains), and now even that pace is impossible. Your newbie gains are grinding to a halt.

The good news is that by the time newbie gains end, the average lifter will have gained a good twenty pounds of muscle over the course of a year. By the time a skinny guy finishes making his newbie gains, he’ll have gained a whopping 40–60 pounds of muscle over the course of a couple of years, depending on how skinny he starts.

By this point, you’ll have quite a muscular physique. And that brings us to the final and most brutal stage of adaptation: building new muscle fibres.

What Happens After Newbie Gains?

As we mentioned earlier, these stages all blend together. You can continue adding nuclei to your muscle fibres for quite a long time, just with increasingly diminishing returns. If you’ve been bulking steadily, by the time you finish your second year of serious hypertrophy training (including training, diet, and lifestyle), you’ll probably be about 80% of the way to your genetic muscular potential. Again, most people don’t build muscle anywhere close to that efficiently, and even the people who bulk properly often take some breaks here and there, but it can happen.

Diagram of muscle fibres splitting into multiple fibres

At this point, your muscle fibres will be as large as those of an athlete, strongman, and bodybuilder (study). You won’t be quite as big as them yet, though, and the reason for that isn’t totally clear. They might have more muscle fibres, but it’s hard to say for sure.

We’re at the advanced muscle-building stage now, which is beyond the scope of this article. That’s a good thing, too, because this advanced muscle growth science is highly theoretical. We know that elite powerlifters have more muscle fibres than intermediate lifters, and we also know that animals are able to create new muscle fibres. With those two facts, we can infer that men are able to build new muscle fibres. But we don’t know for sure.

But the good news is that by this point, you’ll be muscular. And not just more muscular than average, but impressively muscular. You’ll have a strong physique that looks great. Continuing to make progress will be slower and harder than ever before, but you’ll already have a physique that you can be proud of.

And let me tell you, weight training when I was skinny, underweight, and out of shape was a very different experience from lifting weights now that I feel fit and strong. I like this tougher, fitter, stronger body, and so it’s fun to lift weights.

Summary

When we first start lifting weights, our muscles are sensitive to the stress of lifting weights. It doesn’t take much to stimulate a ton of muscle growth or cause crippling muscle soreness. As we adapt to that stress, we grow bigger, stronger, and also tougher. This process of growing tougher is called the repeated bout effect (RBE), and it allows us to handle harder training, but it also makes it harder to continue stimulating muscle growth. This is one reason why beginners are able to build muscle so quickly.

Illustration of a skinny hardgainer building muscle and becoming muscular (before/after).

But the main reason that beginners are able to gain muscle so quickly is because of how far away from our genetic muscular potential we are. When our frames have plenty of room for muscle growth, our bodies build muscle extremely fast. This period of rapid growth is often referred to as newbie gains.

What’s interesting about newbie gains is that because our rate of muscle growth is determined by how far away from our genetic potential we are, it means that skinnier people are starting further away from their genetic potential, and are thus able to gain muscle even more quickly than the average beginner:

Before and after photo of a skinny guy bulking up and becoming muscular.

As a result, skinny beginners are often able to bulk much more aggressively, gaining muscle much faster (and often more leanly) than the average beginner. This accelerated rate of muscle growth slows as we become more muscular, but by then we’re no longer skinny.

However, these rapid rates of muscle growth hinge on following a good hypertrophy training program, eating a good bulking diet, and making the proper lifestyle changes. Most beginners, understandably, don’t know how to do that very well. It takes the average beginner a few years to learn how to combine the various variables together. That’s why you’ll often see such differing rates of muscle growth between research participants, people following dedicated hypertrophy programs, and people winging it in the gym.

If you want to learn how to train, eat, and adjust your lifestyle for muscle growth, along with a full 5-month hypertrophy workout routine, videos teaching all of the lifts, and personal guidance from us in the member community, check out our Bony to Beastly Bulking Program. The workout routine and exercise videos are made by Marco Walker-Ng, BHSc, PTS, PN, a professional (and certified) strength and diet coach with a health science degree, who has helped college, professional, and Olympic athletes bulk up, as well as nearly 10,000 naturally skinny guys.

We’re totally confident that you can do this by yourself. Many skinny guys do. But if you want help, we can help you build muscle faster.

Shane Duquette is the co-founder and creative lead of Outlift, Bony to Beastly, and Bony to Bombshell, and has a degree in design from York University in Toronto, Canada. He's personally gained sixty pounds at 11% body fat and has nine years of experience helping over ten thousand skinny people bulk up.

Marco Walker-Ng is the co-founder and strength coach of Outlift, Bony to Beastly, and Bony to Bombshell, and is a certified trainer (PTS) with a Bachelor's degree in Health Sciences (BHSc) from the University of Ottawa. His specialty is helping people build muscle to improve their strength and general health, with clients including college, professional, and Olympic athletes.