How many reps is best for building muscle?

It’s one of the most common questions guys have about lifting weights.

In this article I’ll breakdown the science behind different rep ranges, so you know exactly what you should be doing to build the most mass.

Bonus: Take my FREE Physique Quiz and find out EXACTLY what workout routine and diet plan is best for you… based on your current body type.

What the Science Says


People generally believe that low reps (1-5) are best for strength, medium reps (6-12) are best for size, and high reps (12+) are best for muscular endurance…

NOTE: The chart above displays this common belief (NOT the scientific truth).

But is there any scientific proof to back up these beliefs?

The answer is yes and no. Let me explain:

  • If your goal is to get as strong as possible, then low reps is clearly best, because it allows you to lift heavier weights…
  • If your goal is to build endurance, then high reps is clearly best, because it allows you to lift for an extended period of time…
  • But if your goal is to build muscle, there’s no obvious answer, because this is an aesthetic goal (NOT a functional goal)

That being said, a number of studies have been done on how different rep ranges affect your ability to build mass. Rather than getting super technical and breaking down all the complex testing methodologies and statistics, I’ll cut to what you care about: the results.

Greg Nuckols of recently conducted an in-depth analysis of the top 20 studies investigating rep ranges, and this was his conclusion:

Of the 20 studies… 17 reported no significant differences in hypertrophy in the most relevant comparison groups… but on average the ‘hypertrophy range’ did slightly better than high reps or low reps.

In other words, different rep ranges caused very little difference in muscle growth.

Yes, the medium range (6-12) had a slight edge, but you can still build muscle efficiently in the low (1-5) and high (12+) rep ranges.

The Real Reason 6-12 Reps is Best


Even though these studies found that rep range does not have a huge impact on mass, there’s still one big reason you should focus on 6-12 reps if your main goal is to build size.

Here’s why…

In order to build mass, you need to maximize the number of high quality reps you do (per muscle group) over the course of each week.

When I say ‘high quality reps’ I mean reps that maintain good form and are still relatively challenging for you to complete. These reps will place enough stress on your body to induce muscle growth, but avoid overstressing your body and extending your recovery time.

By doing a lot of high quality reps, you’ll maintain higher levels of muscle protein synthesis, and build more size.

Here are 3 reasons why 6-12 reps is best for achieving this…

#1: Better Form Than Low Reps

When you’re working with low reps, at an intensity that’s close to your 1 rep max, it’s becomes challenging to control the weight and maintain good form.

While this isn’t a reason to avoid low rep work, your form will be better (on average) when doing medium and high rep work. And this means that your average rep will be higher quality.

Here, higher quality means that you’re more likely to take the weight through a full and proper range of motion (from the first rep until the last). Think of how many guys start half squatting or half benching when they get close to their max. This type of cheating diminishes the ‘efficiency’ of the rep, and hinders your ability to build mass.

#2: Less ‘Burnout’ Than Low Reps

Another advantage of 6-12 reps is that it avoids the ‘CNS Burnout’ you experience with low reps.

The exact physiological processes by which this happens are often debated, but you can’t deny there’s a certain mental fatigue you experience after deadlifting or squatting close to your max.

Even though you aren’t physically tired, your brain feels foggy and you lose motivation to keep working out at a high intensity. And this results in lower quality reps for the remainder of your workout… and less gains throughout the week.

#3: Less Physical Exhaustion Than High Reps

A final reason medium reps are best for building mass is that they avoid the physical exhaustion that comes with high rep work.

It’s simple: after you grind out a set of 12+ reps, you’re fucking exhausted! And this negatively affects your mental focus, and your physical strength for the remainder of the workout… which limits the number of quality reps you will perform, and the amount of muscle you will build.

To sum this section up: 6-12 reps is best for mass because it offers an effective ‘middle ground’.

It allows you to maintain good form and keep the intensity high, without getting too mentally ‘burn-out’ or physically exhausted. And this means you get more high quality reps over the course of the week, resulting in more mass being built.

Best Rep Range by Exercise


Different exercises require different amounts of power, stabilization, and mobility. And this makes different rep ranges better suited to different exercises.

Below I’ll offer my suggestions… but my general recommendation is to go with what ‘feels’ best to you.

If doing more than a few reps of a certain exercise makes it difficult for you to maintain good form, then stick with low reps for that movement. If going heavy and doing low reps makes you feel ‘shaky’, then stick with higher reps for that exercise.

Compound Barbell Movements

Examples: Squats, bench press, overhead press, bent over rows.

Recommended Reps: 5-8

Reason: Barbell compound movements allow you to move more weight (and build more strength) than any other exercises. You should take advantage of this fact and stick to slightly lower reps, which allow you to maximize the amount of weight you’re using.

*Deadlifts are an exception here. For deadlifts I recommend sticking to sets of 3 reps, because it’s a ‘power’ movement that’s better suited to using heavier weights. Also, form can break down after a few reps, and the risk of serious injury is greater than with most exercises.

Compound Dumbbell Movements

Examples: Lunges, goblet squats, chest press, shoulder/arnold press, rows.

Recommended Reps: 8-10

Reason: Dumbbells always involve some degree of instability, so you don’t want to go too heavy. Otherwise you’ll be too focused on getting the weights into place and keeping them balanced, rather than pushing yourself. But these are still compound movements that can build good strength, so you don’t want to go too high either.

Isolation Movements

Examples: Curls, tricep extensions, shoulder flys, abs/core exercises.

Recommended Reps: 8-12

Reason: The point of isolation work is to build size in your ‘beauty’ muscles (arms, shoulders, abs). There’s not much benefit to going heavy, plus they put all of the stress on a single joint (whereas compound movements distribute the load over several joints), so going heavy can quickly lead to overuse injuries in the tendons and ligaments surrounding your joints.

Conclusion: Best Rep Range for Mass?

The best rep range for building mass is 6-12 reps.

It’s been proven to have a slight advantage in studies, and it allows you to pack in a higher number of quality reps over the course of each week.

However, there are still reasons to use other rep ranges. Some exercises, such as deadlifts, are better suited to lower reps for example. 

Also, switching up your rep range when you hit a plateau is an effective way to break through the plateau. For example, using low reps builds more strength and power, while using high reps builds more endurance and oftentimes leads you to improving your form.

Therefore, I suggest you incorporate all rep ranges into your training, while focusing most of your sets in the 6-12 range.

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