This Is How Long It Takes to Build Muscle, According to 4 Fitness Pros

When you’ve got your eye on a big fitness goal, you want to know every nitty-gritty detail that can help you get there, fast. If your goal is to eat more protein, you’re not just curious about how much protein to eat, but what types to eat and when to eat it. If you want to get stronger, you’re not just curious about the best exercises to try but also: How long does it take to build muscle? 

To quell your curiosity on the muscle-building front, we spoke with four experts—a Peloton instructor, a sports medicine specialist, and two exercise physiologists—to get all the details. Ahead, learn how long it takes to build muscle, how long it typically takes for muscle growth to become visible, and more.

How Your Body Builds Muscle

First, a little anatomy refresher: Every muscle in your body contains proteins that form the muscle fibers that power your movements. The protein you eat gets turned into the type of protein your body can use to build muscle in a process called muscle protein synthesis.

Your body’s in a constant dance of breaking down your muscles and building them back up: Every time you work out, that exercise breaks down your muscle fibers a little. When your muscles repair themselves, those fibers build back stronger and bigger, says Jeffrey R. Bytomski, DO, a sports medicine specialist at Duke Orthopedic Surgery and the head team physician for Duke University. 

And that’s really the point of strength training: When you’re used to lifting 10 pounds and then ask your body to lift 15, you send a little signal to your body that it needs to get stronger, says Alex Rothstein, a certified exercise physiologist and the program coordinator of exercise science at the New York Institute of Technology. And it listens: It adapts over time to be able to handle the increased load as long as you keep sending the signal. 

Simultaneously, whenever you eat protein, your body shuttles some to the muscles that need repair. “Adequate protein promotes the remodeling of our muscle tissue,” says Luke Carlson, certified exercise physiologist and founder and CEO of Discover Strength in Minneapolis.

How Long Does It Take to Build Muscle?

Even though you don’t see any major changes right away, you’re building muscle with every workout, Rothstein says, and muscle protein synthesis is constantly happening. But “it takes weeks for the compounding change to be visible to the naked eye,” he says. The experts we spoke with estimate that could be anywhere from four to 12 weeks, depending on various factors.

Visible changes can be noticeable earlier in people who are newer to strength training, Carlson says. That was the case for Peloton instructor Marcel Maurer when he finished his career as a soccer player. Once training for soccer was no longer his top priority, his strength workouts changed, and he quickly noticed new muscle growth in his chest, back, arms, and shoulders. “My body was building bigger muscles to adjust to my workouts, which were shorter but with heavier weights,” he says. 

Besides your previous fitness experience, your age also plays a role: It can be harder to build muscle as we get older because the body naturally loses muscle over time. In fact, after age 30, we lose about 3–5 percent of our muscle mass per decade, according to the Office on Women’s Health.

How Can You Tell If You’re Actually Building Muscle?

You’ll see the most obvious signs by looking in the mirror: As you build muscle (and burn fat), your body composition changes, and your reflection will look more sculpted and muscular.

But again, everyone builds muscle a little bit differently. Setting a rigid goal such as gaining 10 pounds of muscle can leave you disappointed or discouraged along the way if you’re not reaching that benchmark as quickly as you’d like, Dr. Bytomski says.

So don’t forget about the more subtle signs you’re building muscle: Maybe you feel less pressure and strain on your joints or you notice your posture improves, Marcel says. Maybe you find you can do an extra couple of reps of an exercise you’ve been practicing, or you need to increase the weight you grab to keep that move feeling challenging, Dr. Bytomski adds. Perhaps you’re finally able to do a challenging exercise like a push-up that you couldn’t do before.

There might also be a payoff in your daily activities. “Tasks like climbing stairs, getting in and out of the car, carrying the recyclables out, carrying the groceries—everything should feel not as hard,” Rothstein says.

When Does Muscle Growth Become Noticeable?

Visually, you’ll usually notice muscle growth in as little as four to six weeks after beginning training, Carlson says. And you can expect those gains to continue for another year or two. “We will maximize most of our increases in lean muscle within the first 18–24 months of strength training,” he adds.

Remember, it’s not only about the size of your quads or biceps: “Do the strength workouts you like and trust the process,” Marcel says. “It’s more important that you train with happiness before you’re programming a workout only for isolated visual muscle.”

Tips on How to Build Muscle

No matter your age, sex, or fitness level, there are some tried-and-true steps to build muscle anyone can follow.

1. Work Each Muscle Group Twice a Week or More

There’s no one-size-fits-all amount of workouts needed each week to build muscle—everybody is unique and has different ideas of what “muscle gains” look like. That said, there are some general best practices to keep in mind. 

Marcel recommends three 30–60 minute strength training sessions each week. Some people prefer to do five sessions, where different workouts are focused on different areas of the body. Others only have time for two bouts of weightlifting each week (which meets the Department of Health and Human Services’ recommendations for adults.)

Ultimately, you can decide how often to strength train as part of your individual muscle-building journey. But you’re likely to see the biggest changes if you can work a specific muscle group every 48–72 hours or so, Rothstein says. For example, if you do a back workout on a Monday, you should work your back again Wednesday or Thursday. That schedule keeps the muscle protein synthesis process revved up in those muscles, he says.

Focusing on which muscle group you’re working also gives you a natural way to structure your rest days: Making Tuesday a lower body day, for example, automatically gives your upper body that day off, Rothstein says.

Not sure where to start? You can find all sorts of strength workouts on the Peloton App, in addition to personalized strength plans and plenty of guided programs with recommended workout schedules.

2. Fix Your Form

If you’re working out multiple times a week, hoping to build muscle, but you’re doing every exercise with poor form, you’re more likely to hurt yourself and have to stop than develop any noticeable gains.

Start with light weights and make sure you really get comfortable with new movements before lifting heavier, Dr. Bytomski says. Take a class on the Peloton App or work with an instructor or personal trainer who can help you learn unfamiliar movements. Then watch yourself in the mirror or take a video you can replay later and critique your own form. Make any necessary adjustments to get the most out of each movement.

3. Up the Intensity

“We don’t need very much strength training to increase muscle, but we do need to work with a high level of intensity,” Carlson says. In other words, you can build muscle with just a couple strength-training sessions per week, but only if you’re giving those muscles a good workout. You should feel like you can’t do another rep by the end of each set, he says.

If you’re not seeing results, get really honest with yourself about the level of effort you’re putting in. “The biggest mistake people make is they don’t have enough stress [on their muscles],” Rothstein says. “If you grab some two-pound weights and you’re doing bicep curls with one arm and texting with the other arm,” for example, you’re probably not working hard enough, he says.

4. Prioritize Protein

Simply put, you have to eat enough protein if you want to build muscle. “Without adequate protein, it becomes difficult to increase our lean muscle tissue,” Carlson says.

There are a number of different calculations for estimating your protein needs. But an easy-to-remember rule of thumb is about 1 gram of protein for each pound of your body weight, Dr. Bytomski says.

When gaining muscle is the goal, many people turn to protein powders and shakes to make sure they’re getting enough. But try to hit your goals with food first, he says. It doesn’t have to all come from meat: You can add high-protein snacks like Greek yogurt, cottage cheese, and nut butters to your rotation.

Think too about when you eat your protein: Your body can use more of it if you spread it out throughout the day, Rothstein says, rather than having a heavy, protein-rich dinner but getting minimal protein during the rest of the day.

5. Get Plenty of Sleep

Sleep gives your body extra time to repair your muscles while you’re not using them. “You break down the muscles during your workout, and when you sleep is when you build them back,” Dr. Bytomski says. Dedicating yourself to your workout program but then only getting four hours of sleep each night is sabotaging your progress, he says. Instead, aim for at least seven hours each night.

Can’t seem to log more winks? Check your sleep hygiene: Make sure your bedroom is dark, cool, and quiet; tuck your phone away an hour or so before bed; and create a relaxing wind-down routine that helps set the stage for rest.

6. Keep a Workout Log

Once you’ve been exercising long enough, you’ll probably find yourself face-to-face with a dreaded plateau. To avoid getting stuck in such a rut, you have to keep challenging yourself. This is typically called progressive overload, and it means gradually increasing the stress on your body so your muscles keep adapting over time.

Rather than just guess at this process, it’s generally a good idea to measure it. That means creating some kind of workout log, whether you keep it in a note on your phone or go old school with pen and paper. Every time you work out, write down the exercises you did, your reps, sets, and weights used, and how you felt. That will give you a clear picture to reflect on and build from over time, Dr. Bytomski says. When things start to feel easy, it’s time to ramp up the volume.

The Takeaway

Your body builds muscle by turning the protein you eat into muscle protein. When you exercise, you create tiny tears in your muscles, and your body builds them back bigger and stronger than before. You need to get plenty of protein (about 1 gram per pound of your body weight) to fuel this process and regularly stress your muscles—at a high intensity—to see visible results. It’s generally a good rule of thumb to work each muscle group twice a week. The Peloton App is full of muscle-building strength workouts that will shake up your routine and keep you motivated to reach your goals. 

Although every workout helps you build muscle, you probably won’t see any noticeable changes until four to 12 weeks of consistent dedication to building muscle. Along the way, it’s important to get plenty of sleep, correct any form mistakes, and track your progress, too. And of course, make sure you find joy in your strength training journey to feel stronger from the inside out.