When it comes to muscle building, it’s all about repetition and being consistent with strength training. You might see some people gain muscle quickly than others, which can be confusing. It’s important to remember that building muscle is a marathon and not a sprint. Having a good routine and giving yourself a realistic timeline will yield the best results.
Muscle growth — specifically optimal muscle protein synthesis — depends on several key factors. Your diet and genetics both play a role, as does sleep. Read on to break down how muscle growth works — and how long it can really take.
How muscle growth happens
Each muscle is made up of muscle fibers, which are cylindrical cells. Weight training breaks them down and recovery helps them grow.
Building muscle involves the repair of microtraumas in your muscle fibers. Here’s a breakdown of this extremely complex process:
1. Each muscle is made up of thousands of tiny muscle fibers.
2. When you lift weights (or do body weight exercises), your muscles endure tiny injuries throughout their fibers.
3. Then, when you rest your muscles, your body begins repairing your damaged muscle cells.
4. The repair process involves fusing torn muscle fibers back together, as well as laying down new proteins within each muscle cell.
5. Your muscles become bigger and stronger as a result of the repair process.
Keep in mind that the above is a tremendously simplified version of what actually happens in your body after a weight training workout. In reality, the process includes more than just your muscles — your nervous system, circulatory system and endocrine system all contribute to muscle repair and growth.
How long does it take to see muscle growth?
Building muscle is super hard. If it was easy, we’d all be ripped.
There’s no one muscle-building timeline because several factors affect your ability to build muscle mass, including:
Your protein intake: While all macronutrients have their roles, protein is king when it comes to building muscle. Your muscles need adequate protein to repair themselves after the stress of weight training. Without enough protein, muscle growth stagnates.
Your calorie intake: If you don’t eat enough calories on a daily basis, you won’t build muscle even if you eat a lot of protein. To build muscle, your body must create new tissue, and it can’t create something from nothing. Extra fuel from extra calories expedites muscle recovery and growth. This is one reason many people never reach their muscle growth goals — they aren’t willing to deal with the extra body fat that comes along with a muscle-building phase.
Your sleep schedule: Lifting weights while sleep-deprived isn’t a smart strategy. You might see some gains, but you definitely can’t optimize muscle growth when you don’t give your body a fighting chance to recover.
Your lifting routine: If you’re trying to build muscle, you should know about two key strength training concepts: frequency and volume. Frequency refers to how often you train a muscle or muscle group, while volume refers to the total load you stress a muscle with.
For example, if you perform three sets of 10 reps on squats using 100 pounds, your total volume is 3,000 pounds. More volume and higher frequency typically equate to more muscle, unless you reach the point of overtraining.
Your training age: The more advanced you are, the less muscle growth you’ll see (yeah, that sounds backward). Everyone has a maximum genetic potential for muscle growth, and the closer you get to yours, the harder it gets to build more muscle.
Your actual age: Like a lot of things, building muscle gets harder as you get older. Sarcopenia, or loss of muscle mass and function, is actually a big problem in older adults. That’s one reason why it’s so important to stay active as you get older.
Other major factors include your genetic potential for building muscle (which is impossible to quantify without lab testing, and even then, kind of wishy-washy) and your testosterone levels — which is why men typically have more muscle than women. Other hormones, including human growth hormone and insulin growth factor, also play a role in muscle growth.
All that said, the muscle-building process starts the moment you challenge your muscles to do something. True beginners might see muscle growth within six weeks of starting a resistance training program, and advanced lifters may see results within six to eight weeks of switching up their usual strength training regimen.
Regardless of fitness level, building muscle takes several weeks, even when your diet, sleep and training regimen are all dialed in to optimize muscle growth.
Can you build muscle doing cardio?
Cardio that involves high-volume weight training can help you build muscle.
This depends on your definition of cardio and your training age. Most people won’t build much muscle from traditional cardio, such as walking or jogging on a treadmill, and people who’ve been training for a long time definitely won’t build new muscle through traditional cardio. It doesn’t recruit your muscles in a way that sends a muscle-building signal to your body.
However, cardio that involves high-intensity exercises like plyometrics (think jump squats) or high-volume weight training can help you build muscle to an extent. Using a treadmill to practice sprinting hills, hiking, and other outdoor cardio can also contribute a small amount to muscle mass, especially for beginners. People with a long training history may not see as much success with cardio.
Although cardio can improve your overall fitness and help build muscle in select scenarios, strength training remains the best way to build muscle mass.
Muscle growth FAQs
How long does it take to build muscle?
There isn’t a fixed timeline for how long it’ll take to build muscle. It can take several weeks to several months. Beginners will see results earlier than intermediate or advanced people. However, the main crux is to find and follow the right combination of resistance training, eating habits and rest. These will help your body achieve muscle protein synthesis — the process that builds muscle — and result in muscle growth.
How long does it take to have visible abs?
Like any other muscle group, training your abs will help them grow and become visible, but there is also an added variable of body fat. An expert we consulted mentioned a typical person will need to have 15% body fat (or less) for abs to be visible. However, this number can change based on your genetics.
Do your muscles grow on rest days?
Yes, muscles grow on rest days. Our muscles don’t grow while exercising because working out results in small muscle tears. Rest days allow your muscles to repair and build back up from exertion. If you don’t take adequate rest days, your muscles will break down and throw off your progress. Focusing on proper nutrition and getting enough sleep is essential during your rest days.
Which muscle grows the fastest?
When starting a new strength training program, you may notice more growth in select muscles. Generally, the bigger muscle groups will respond quickest to strength training, including the biceps, back and quads. You may notice that your abdominal muscles, hamstrings and forearms will change more slowly.
