How much muscle and strength can naturally thin women gain? And how quickly can they do it?

So you start lifting weights. How much muscle can you expect to gain in your first few months? How much weight should you be adding to the bar each week? And how big and strong can you become during your first year? What are good lifetime goals? Or maybe you’ve been lifting for a while and you’re wondering how strong you should be by this point.

Most women are trying to get toned, lose some fat, you know the deal. They don’t want to get too bulky. That might suit their goals just fine, but it’s going to make it almost impossible for them to gain much muscle and strength.

…But what if you’re willing to gain weight? What if you want “bulky” hips? What if you want to become strong? That changes things. We can do better. Much better. In fact, I have a feeling you’re going to be pretty amazed about what you can do even in just your first year of lifting.

So, to figure out how much muscle and strength you can expect to gain, let’s break the question down into two parts:

1. How much muscle can a naturally thin woman expect to gain?

2. How much strength can she expect to gain? 

Let’s dig into the science.

How much muscle can the average woman gain in her first year of lifting?

Before we can talk about how much muscle a naturally thin woman can build in a year, we need to talk about what sets her apart from the average woman. The main difference is that by the time the average woman reaches adulthood, she’s naturally accumulated a fair amount of muscle mass on her frame, partly due to her genetics and partly due to the fact that she’s overweight.

According to the CDC, the average woman weighs around 170 pounds by the time she reaches adulthood, which represents a BMI of about 30. According to Steven Heymsfield, author of Human Body Composition, around 30% of the average woman’s bodyweight is muscle mass. This means that the average woman starts off with roughly fifty pounds of muscle.

The next thing we need to consider is her genetic potential—how much muscle mass can her frame hold? It seems like the average woman’s frame can hold around seventy pounds of muscle, meaning that over the course of her lifetime, she can “only” gain another twenty pounds of muscle. (Twenty pounds of muscle is quite a lot, but it probably pales in comparison to the amount of muscle that you can build.)

However, this growth isn’t linear, it’s logarithmic. During her first year of lifting, the average woman is able to get about halfway to her genetic potential, gaining around ten pounds of muscle. In her second year, that rate of muscle growth will be cut in half, and then cut in half again the next year. Like so:

This initial explosion of growth happens because when she starts lifting weights, her muscles are still extremely sensitive to this new stimulus and still have incredible growth potential. This period of rapid muscle growth is called newbie gains, and it allows the average woman to gain around a pound of muscle per month. She might even be able to lose some fat while doing it.

This rapid growth is possible because her muscle fibres are still small, making it easy for her nuclei to manage them. In fact, her nuclei are already capable of handling significantly larger areas, so her muscle fibres can simply expand, like so:

After a few months, she’ll quickly reach the point where her myonuclear domains are maximized, at which point building muscle starts to get harder. It starts becoming difficult to gain muscle without gaining weight overall, making simultaneous muscle growth and fat loss almost impossible.

Now she needs to bring new nuclei into her muscle fibres before they can grow any bigger. Sort of like needing to hire more managers as your company grows. It looks like this:

Admittedly, this example is oversimplified, and there are other known factors that contribute to the slowing rate of muscle growth (such as the repeated bout effect), but the main takeaway here is that our muscles grow quickly at first, and then as we get closer to our genetic potential, our rate of muscle growth slows.

So all things considered, most experts agree that the average woman can expect to gain around around ten pounds of muscle during her first year. And to be clear, ten pounds is a lot of muscle. That’s enough to add a few inches around her hips and shoulders, dramatically transforming her physique.

Then in the years that follow, she gets closer to her genetic potential, and it gets harder to gain more muscle and strength, which sounds like a total bummer, but keep in mind that by then she already has a totally killer physique, so there isn’t as much of a rush to keep improving:

Once you’ve spent a year or two fighting to gain muscle and strength, you don’t need rapid progress anymore, you can enjoy the benefits of having a strong, healthy, and athletic physique.

This rate of muscle growth raises a couple questions, though:

  1. How come most women who lift weights hardly gain any muscle ever?
  2. How come our members are often able to gain ten pounds in just a few months?

The first question is easy to answer. This rate of muscle growth assumes that you’re following a good bulking program. In order to build muscle quickly and consistently, you have to:

  • Follow a serious lifting program. Most exercise programs aren’t designed to help women become bigger and stronger. Even most lifting programs for women are more about cardio and endurance than about gaining muscle mass. (Strong Curves by Bret Contreras, PhD, is a great book and a possible exception to this, but it still assumes an overall goal of weight loss.)
  • Fight to get stronger. To gain muscle, you have to progressively lift heavier and heavier weights. If you start off doing goblet squats with 30 pounds, next week you should be fighting to lift 35. And then 40. Then you switch to a front squat with 45 pounds, and so on. That’s how you gradually work your way up to a 245-pound back squat (which how much you’ll be able to squat a few years from now).
  • Gain weight. If you aren’t gaining at least a pound on the scale every month, you won’t be able to gain muscle mass anywhere near this quickly. This explains why most women won’t gain anywhere even close to ten pounds of muscle during their first year of lifting weights—they aren’t gaining enough weight overall.

Because of how deliberate you need to be about building muscle, and because of how uncommon it is for women to intentionally gain weight, most women aren’t going to exercise in a way that will help them build a significant amount of muscle. And that’s fair. The average woman is overweight. Weight gain probably isn’t her goal in the first place.

If you’re someone who’s deliberately trying to gain weight, though, you can absolutely hit this target.

In fact, like we mentioned above, if you’re starting off thinner than the average woman, you should be able to gain your first ten pounds within just a few months. And we’re not talking about getting fat or bulky or anything, we’re talking about building up a strong, badass physique:

Okay, on that note, now that we’ve covered how much muscle the average woman can gain, let’s talk about how much muscle a skinny, thin, or generally underweight woman can expect to gain in her first year of lifting weights.

How much muscle can a thin woman gain in her first year?

So the average woman weighs 170 pounds, has 50 pounds of muscle on her frame, and can add another 20 pounds over the course of her lifetime, 10 of which she can gain in just the first year.

Now let’s imagine a naturally thin woman. Let’s say that she’s the same height but only weighs 100 pounds. She’ll likely have slightly thinner bones, a narrower frame, and a smaller stomach, which accounts for some of the weight difference, but most of the weight difference will be due to the fact that she’s carrying far less muscle and fat. For the sake of this example, let’s say that only 25% of her weight is muscle mass. This gives her just 25 pounds of muscle mass on her frame. Half as much muscle as the average woman. She’s starting behind the starting line, like so:

As you can see, given that we see diminishing returns the closer we get to our genetic muscular potential, if she’s further away from her potential, then she’ll be able to build muscle more quickly.

So to flesh out this theory, the next thing we need to do is determine this naturally thin woman’s genetic muscular potential. After all, it doesn’t matter how far away she is from the average genetic potential, it matters how far away she is from her genetic potential.

The best researcher looking into this question is Casey Butts, PhD, who found that the genetic potential of a hardgainer is about 5–10% lower than average (due to having thinner bones and smaller frames). So if the average woman can hold around 70 pounds of muscle, a naturally skinny woman can expect to hold about 63–67 pounds of muscle. That’s a disadvantage, sure, but not a significant one. In fact, given how few women get anywhere even close to reaching their potential, there’s nothing stopping you from becoming far curvier and stronger than almost every other woman you come across:

Alright, going back to our example, we have a 100-pound woman with 25 pounds of muscle on her frame, with the genetic potential to hold up to 67 pounds of muscle. That puts her a whopping 42 pounds of muscle away from her genetic potential!

Given that she’s starting so far away from her genetic potential, she’s starting at the best possible point on the muscle growth curve: right at the very beginning:

This is going to allow for a period of even more rapid growth when she first starts lifting weights, allowing her to quickly catch up to the average woman, at which point she can expect to start gaining muscle at a more typical pace.

But don’t skinny women have worse muscle-building genetics? When I first started trying to build muscle, I assumed that being skinny meant that I wouldn’t be able to build muscle very quickly. That was confirmed by the fact that I was trying everything I could to gain weight and still couldn’t get the damn scale to budge.

Furthermore, the term “hardgainer” is sometimes used to describe someone who struggles to build muscle. The way we use the term, though, a hardgainer is someone who struggles to gain weight. 

I know that sounds like a weird distinction to make, given that you need to gain weight in order to gain an appreciable amount of muscle, but our struggle to gain weight has little to do with our muscle-building genetics and more to with having higher metabolisms and smaller appetites/stomachs. In my case, at least, I wasn’t failing to build muscle because I was having a poor response to lifting weights, I was failing to build muscle because I couldn’t get into a calorie surplus—I was failing to gain weight. It was a diet issue.

Once you learn how to eat enough calories, I suspect that you’re going to respond incredibly well to lifting weights. With a proper lifting program, you should be able to greatly exceed all the expected rates of muscle growth:

What if you have naturally small hips? We’ve been talking about overall muscle mass, but one question we get is how big you can specifically build up your hips. After all, many of our members don’t want to bring their biceps to their full genetic potential, but they do want to see how big they can build up their glutes.

Even if you have poor genetics, I think you should be able to build up your glutes to about 90–95% of the size of the average woman who reaches her full potential. And keep in mind that most women aren’t going to get anywhere even close to their full potential, even if they lift weights their entire lives. If you take this seriously, you should expect to be able to build remarkably powerful hips.

Lifting weights gives you quite a bit of control over the type of physique you can build. We generally recommend aiming for overall strength with some extra emphasis on building up your hips, given how strong your hips can become, and how much potential they have for growth, but the cool thing is that you can build the physique that you want.

How is it possible to build muscle that quickly? The research shows that on average women who are new to lifting weights seriously can gain about a pound of muscle per month. There are studies showing far greater rates of muscle growth than that, but, at least on average, most experts agree that a woman following a good muscle-building program can realistically expect to gain about a pound of muscle per month. However, the research also shows that rates of muscle growth vary highly from person to person. While gaining two pounds of muscle per month may be the average, some women are able to gain muscle up to three times as quickly (study).

Isn’t gaining weight that quickly going to cause fat gain? If you gain weight more quickly than you can build muscle, you’ll gain fat. That’s why it’s important to gain weight at the right pace. Also, keep in mind that if you want to maintain, say, a 20% body-fat percentage as you bulk up, that means that 20% of the weight that you gain can be fat without even raising your body-fat percentage.

Furthermore, the more muscle you gain, the better your insulin sensitivity will become, and the easier it will be to maintain a lower body-fat percentage in the future (study). This is one of the great advantages of building muscle.

Finally, Bret Conteras, PhD, known for being the top glute growth researcher in the world, has used our Bony to Bombshell transformations as examples of women being able to build a ton of muscle without gaining any noticeable fat.

So, yes, when gaining weight you can certainly gain fat, especially when doing it quickly. But is that going to actually make you fat? No. It’s not something you really need to worry about.

Is gaining that much muscle going to make you look blocky / bulky / increase your waist size? We have a lot of members trying to gain serious amounts of weight, but they aren’t necessarily trying to just get big, they’re trying to build an hourglass figure.

The muscles in your waist are small, the muscles in your shoulders are a little bit bigger, and the muscles in your hips are absolutely enormous—they’re the largest muscles in your body and have the most potential for growth. This means that as you build muscle, your waist should stay quite small, your shoulders will grow a little bigger, and your hips will explode in size.

Here’s how Ioulia’s proportions changed while following an overall strength program with only a slight emphasis on increasing her hip size and strength:

However, if you want to further emphasize building an hourglass figure, there are a few things you can do:

  • Don’t do a ton of extra ab and oblique work. The more you train a muscle, the bigger it will grow. If you spend a lot of time training your abs with crunches and side bends and whatnot, they’re going to grow, and so will your waist.
  • Don’t fear transverse abdominal work. There’s a muscle underneath your abs called the transverse abdominal muscle. This is the the muscle that works to stabilize your core during heavy compound lifts, such as the squat and deadlift. It functions sort of like a corset, pulling your core tighter. (Some people even practice doing stomach vacuums to further strengthen their transverse abdominal muscles.)
  • Get your hips extra strong. In addition to getting strong at the squat and deadlift, you can also fight to get strong at the glute bridge and hip thrust. If you want guaranteed glute growth, work your way up to a 315-pound glute bridge and a 225-pound hip thrust. (Doing tons of light band stuff or burning yourself to a crisp with high-rep sets of lunges isn’t going to build muscle muscle much unless you’re also building a strong foundation of strength.)

Unless you’re intentionally doing a ton of core exercises to bulk up your waist, or unless you’re gaining a ton of fat as you bulk up, you should be able to build powerful hips and strong shoulders without seeing a noticeable increase in your waist measurements. Some of our members have even been able to shrink their waist measurements as they gain muscle overall.

Also keep in mind that lifting weights won’t change your bone structure. If you have thinner bones and longer limbs, building muscle isn’t going to change that. Your hips, shoulders, and thighs will grow a great deal, but that’s not going to make your ankles, wrists, neck, or waist any bigger. You’re not going to morph into a different body type. You’ll still be a naturally thin woman, just with a strong physique and powerful curves.

Besides, if you’ve read our article about attractiveness, you know that our approach to building a body that looks better is to build a body that’s stronger, healthier and fitter—a body that’s conspicuously healthy.

How strong should a woman be after a year of lifting?

After her first year of lifting, the average woman should be able to bench press 125lbs (55kg), squat 200lbs (90kg), and deadlift 250lbs (115kg). Those numbers might seem high to you, and truth be told, they might be.

Most naturally skinny women are able to laugh at the muscle growth standards, shooting way past them—sometimes gaining muscle 2–3 times more quickly than the average woman—but then these basic strength standards can seem totally out of reach.

So, first of all, where do these strength standards come from? The most credible source I’ve found is Greg Nuckols, BS, from Stronger by Science (an incredible strength training blog). He took a survey of his readers, all of whom are serious about both powerlifting and science, but who ranged from beginners all the way up to advanced lifters. He found that within a year of serious lifting, the average woman was able to squat 200 pounds. Furthermore, Greg mentions that with proper workout programming and coaching, you should be able to do even better than that.

However, we also need to consider how much these women were able to squat when they started lifting. In this case, the average women started off squatting around 145 pounds. So within their first year of lifting, they only added 55 pounds to the bar.

The average women were adding less than five pounds to the bar each month.

This is an “aha” moment for a lot of us.

Wherever you’re starting, just like them, you can gain strength five pounds at a time.

In our experience coaching naturally thinner women, we hardly ever see someone who’s even able to do back squats to depth with proper technique, let alone someone who can do it with 145 pounds on their back. We usually start our members off with simpler progressions, such as dumbbell goblet squats. This simpler squat variation allows them to build just as much muscle while learning how to squat with great technique. (It’s great for improving hip mobility, core stability, and posture.)

Over the course of a month or so, we’ll often see our members move from a 30-pound goblet squat up to a 50-pound goblet squat, showing 5 pounds of strength added per week, which is incredibly rapid progress. However, since we’re starting behind the starting line, it can still take us a few extra months to catch up.

How long will it take a skinny woman to become strong? When it comes to developing strength, the most important to keep in mind is the relationship between muscle size and muscle strength. The bigger your muscles are, the more force they’re able to produce. This means that if you’re a thin woman who wants to become stronger, then priority number one should be increasing your muscle size. As your muscle mass increases, you’ll see proportional increases in strength.

It also works the other way. If you want to increase your muscle size, you need to be fighting to gain more strength. Getting your heart rate up and feeling the burn won’t do much to increase muscle. You have to build a foundation of strength and then fight to lift heavier weights every workout.

So, how long should it take a skinny woman to work up to a 200-pound squat? That depends on how skinny she’s starting, but since we’ve already covered rates of muscle growth, we can mock up a hypothetical example.

The average woman starts off with fifty pounds of muscle and is able to gain ten pounds of muscle during her first year, bringing that up to sixty pounds of muscle overall. This brings her 145-pound squat up to 200 pounds.

Going back to our example of the skinny woman who’s starting off with 25 pounds of muscle, we see that she’s able to gain more like twenty pounds of muscle during her first year, bringing her muscle mass up to about average (albeit with less body fat). At this point, given that muscle mass and muscle strength are almost perfectly correlated (study, study), we’d expect her to be able to squat 135–145 pounds.

Over the course of the following year, we’d expect her to be able to gain muscle mass and strength on par with the average woman during her first year, bringing her squat up to around 200 pounds. Then, with continued training, she should eventually be able to squat over 245 pounds, bench over 145, and deadlift over 300.

If we want to get strong, we have to get big; if we want to get big, we have to get strong. And for skinny women trying to become both big and strong, that’s absolutely perfect. In fact, being willing to gain weight on the scale will put you in a better position to gain strength than most other women.

Anyway, all things considered, as naturally thinner people, it takes a little longer to build a big and strong physique. Not that much longer, mind you—maybe an extra 6–12 months, depending on how skinny you are to begin with.

You will catch up. These strength standards aren’t insane. You’ll be squatting over 200 pounds soon.

We also have a genetic advantage: our leanness. Even skinny-fat women aren’t dealing with the same propensity for obesity that the average woman is—not even close. And the more muscle you gain, the easier it becomes to stay lean (study). If a skinny-fat woman gains 20–30 pounds of muscle, gets in the habit of lifting, starts eating a better diet… staying lean is probably going to become second nature for her.

Going back to our example of the 100-pound woman who gains twenty pounds of muscle, that only puts her at 120 pounds. Even if she gains some fat while doing it, that might only bump her up to 125 pounds. At this point, she has as much muscle mass as the average woman, but she’s still weighing 45 pounds less. This is because she’s still significantly leaner than average. You might start meeting even the more advanced strength standards while still being quite light overall.

That’s the edge us naturally thinner hardgainers have. We can build muscle very quickly, and if we do it properly, we’ll be able to maintain a lean and strong physique year-round. Even if we’re only able to get 90–95% as big as other serious lifetime lifters… that’s probably bigger and stronger than we thought we could be anyway.

But wait a second… If you train at a standard gym, you may have noticed that the vast majority of women stay weak forever. Most women, even with a decade of lifting experience, aren’t squatting anywhere even close to 245 pounds.

In fact, if you do a set of squats with a couple plates on the bar in a commercial gym, you’re going to draw stares.

Why are so many women failing to become strong?

The good news is that it has nothing to do with genetic variation. Even if you have poor genetics for building muscle, you can almost certainly still get your squat over 225 pounds, your bench over 135, and your deadlift over 300. The trick is that you need to build a bunch of muscle in order to do it (which is probably your goal right now anyway, so that’s great).

And just because you’re starting with a thinner frame or bone structure, there’s nothing stopping you from becoming incredibly strong. Some of the best lifters in the world have fairly small frames. Jen Thompson is a great example. So is Marisa Inda. And so is Jessica Buettner:

Not that you need to take your lifting to an elite level like them, but certainly don’t place artificial limitations on yourself just because you happen to be thin right now. Chances are that if you want to build an incredibly powerful body, you have every opportunity to do so.

The real reason that most women fail to become strong is because:

  • They can’t find any actual muscle-building programs. Most of the fitness programs out there simply aren’t designed to help women gain size and strength. Even the dedicated lifting programs tend to be more about toning and cardio than building a powerful body. Everyone has different goals, and that’s fine—these programs are popular for a reason—but if you actually want to get bigger and stronger, you have to lift with those goals in mind.
  • They don’t use coaches. Right when we started beta testing the very first version of our muscle-building program for women, we realized that we needed to include online coaching with every membership. We know that our members are going to run into problems and plateaus, they’re going to have unique circumstances, they’ll benefit from feedback on their lifting technique, and they’ll have unique goals.  We need to be there to help them through all of that. That’s the only way that we can guarantee progress.
  • Intermediate lifters fail to put in enough effort.
  • Beginners lack consistency. 

If you have big goals and you approach them with a passion, you’re going to be able to accomplish incredible things, blowing past the average lifter in no time. But if you aren’t building muscle properly, you’re not going to gain enough muscle mass to get anywhere even close to these muscle growth or strength targets.

The other thing to keep in mind is that progress requires getting a few things right all at once. If people don’t approach bulking properly, it’s not that they’ll progress more slowly, it’s that they won’t progress at all—ever. Zero gains per week adds up to zero gains per year.

In fact, it’s possible to spend decades lifting weights without ever gaining more than 5–10 pounds of muscle and without ever even matching the strength of someone who followed a good program for a single year. If you never do this properly, you might go your entire life without ever knowing what it’s like to be have a strong, healthy body.

This is great news in the sense that we have every opportunity to become far better than average. But it’s bad news if you were hoping that this would be a walk in the park.

There’s also the issue of people underestimating their potential, which is why I wanted to write this article in the first place. A recent study published in Nature split the participants into two random groups. They told half the participants that they were genetically gifted, and they told the other half that they were at a genetic disadvantage. Those who thought they were genetically gifted performed markedly better. (Greg Nuckols wrote up a good breakdown of the study here.)

You have to expect a lot of yourself and then truly fight for it in order to reach your full potential. If you keep thinking that being naturally skinny is holding you back, it will.

So, how much size and strength can a woman gain?

  • The average woman can gain 10 pounds of muscle in the first year. The average woman weighs 170 pounds, starts off with fifty pounds of muscle on her frame, and can add another twenty pounds over the course of her lifetime, ten of which she can gain in just the first year.
  • Skinny women start off with less muscle mass, but they catch up quickly. A thin woman might weigh more like 100 pounds, start off with 25 pounds of muscle on her frame, and then add another forty pounds of muscle over the course of her lifetime, twenty of which she can gain in just her first year.
  • The average woman can squat 200 pounds after a year of serious lifting. The average woman starts off fairly strong and will gain a bit of strength on top of that, going from a 145-pound squat up to a 200-pound squat in her first year, and then gradually working up to 245 pounds over the course of the next few years.
  • Strength and size are almost perfectly correlated. Even if your ultimate goal is to become strong, you should start with a heavy focus on gaining muscle mass. As you start to develop bigger muscles than the average lifter, you’ll start to become stronger than the average lifter. This can be lift-specific as well. If you build up an impressively big butt, you’ll be able to hip thrust impressive amounts of weight (and vice versa).
  • Thin women start off with less strength but catch up quickly.  Although thin women start off with less muscle mass, reducing their ability to lift as much weight, they can also build muscle at an accelerated pace, allowing their strength to catch up very quickly.
  • Our potential is quite high. Most women aren’t failing to hit these standards because of genetic limitations, they’re failing because they aren’t following good muscle-building programs, they aren’t seeking the advice of qualified strength and conditioning coaches, and they aren’t pushing themselves consistently. Even if you’re very thin right now, with a few years of good lifting, you should be able to squat over 225 pounds, bench over 135, and deadlift over 300—even with bad genetics.

If you want a structured lifting and nutrition program that will help you become stronger and curvier, guaranteed, then you’ll love our Bony to Bombshell Weight Gain Program for Women. And if you hit a plateau along the way, we’ll guide you through it in our coaching community, ensuring that you’re able to march steadily closer towards your goals.

Alright, that’s it for now.

I’ll leave you with our member-turned-coach, Reetta, doing infinite chin-ups:

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