Premier Private Personal Trainer & Online Coach

How To Stop Having Skinny Arms - Your Complete Guide

By: Zack Mathews, NASM CPT, CES, & PES. PN-L1

Skinny arms

Having skinny arms can leave you feeling frustrated and self conscious.  I know from experience.  Prior to learning how to lift weights, I was the one Googling how to get big arms if you’re skinny.

Check out the twigs on those scrawny arms I had!

how to get big arms when you're skinny

6 Reasons Why Your Arms Are Skinny

When it comes to your skinny arms, the main reasons why they are like that could be from one or a mix of poor genetics, you don’t train your arms hard enough, you workout with bad form, you have poor exercise selection, you perform your reps too fast, and/or you aren’t eating enough to stimulate muscle growth.

Are Skinny Arms Caused By Genetics?

One of the main reasons why you have scrawny arms is because of something you can’t control, genetics!  Everyone is built different and can you may be slimmer or bigger in some areas versus others.  For most people that have an ectomorph or skinny fat body, they naturally have long, thin limbs, which leaves then with skinny arms.

There is nothing wrong with that but know that it can be harder for you to build muscle than someone that has shorter arms.  That’s just the way it is!

You Aren't Training Your Scrawny Arms Hard Enough

shutterstock_318400742 (1)

Learning proper intensity is something that comes from experience in the gym.  It's very common to think you are using a weight that is challenging enough, but in reality, you could do more.

I've had online clients that tell me their workout took 20 minutes and it wasn't that hard.  I know that they aren't training hard enough because I know that workout should take 50 - 60 minutes and I've done enough similar workouts to know that if you were pushing it on each set, you would be exhausted!

We'll chat more in the next section about how you make sure you know that a weight is heavy enough.

Your Arms Won't Grow Because Your Form Is Bad

If I was to take a peak around my gym at any given time, I could easily find a few people that are lifting incorrectly.  Even though most arm movements are easier to learn than a complex movement, it’s still common to mess up the movement.

When it comes to skinny arms, this can be because you are using weights that are too heavy so you’re cheating and allowing other muscles to help.  It could also mean you never learned how to do the exercise correctly and are using other muscles besides your arms.  Both are very common occurrences. 

Not Enough Volume

In order for a muscle to grow, you need to provide enough of a stimulus on that muscle through direct training and adequate volume.

If you’re only doing 1 - 2 exercises a week for your skinny arms, most likely nothing is going to happen.

Ideally you will do 8 - 10 hard sets for your biceps and triceps at least twice a week.  This number is subjective and will depend on your current experience.

  • If you’re new to the gym, one day will be enough.
  • Already casually working out?  Add that second day.
  • Advanced lifters can add a third day to get the ball moving with skinny arms.

Additionally, ensure that you are picking exercises that directly work your arms.  You’ll benefit from big compound exercises like bench press and chin-ups since they work your arms, but adding in the direct work will put the volume in the right place and your arms will grow.

Performing Reps Too Fast

Everyone is guilty of this at one time or another.  Beginners are especially susceptible to rushing through a set while they are learning to lift weights.

People often think muscle growth comes from lifting the weight and ignore the lowering portion, but you gain muscle from both.

Slowing your reps and taking 2 - 3 seconds to lower the weight will create more time under tension and can help your muscles grow. 

I talk about more techniques like this in my article How To Make Lighter Weight Feel Heavier.

Not Eating Enough Calories & Proteins For Your Arms To Grow

In order to maximize your muscle growth, you need to be in a calorie surplus.  That means you are consuming more calories than your body needs in a given day and the excess calories will be stored as fat or muscle.  If you are lifting weights and eating enough protein, your body will prioritize muscle.

If you do everything right with you training and still can’t figure out how to get big arms, you might not be eating enough.

Take a period of time where you track your calories and see how many you are consuming. Generally speaking, multiplying your weight by at least 16 will help get you in a calorie surplus.

What You Can Do For Skinny Arms - 6 Proven, Effective Techniques

Skinny Arms Need To Be Trained Close To Failure

The trick to get big arms when you’re skinny is to have intensity in your workouts.  If you are casually doing an exercise and you get done without being tired, you’re going to be spinning your wheels for years.

When performing a set to grow your arms, you need to be getting within 1 to 2 reps of technical failure.

Technical failure is when your form starts to suffer and you’ll start using other muscle to help get the weight up.

Let’s see this in action:

If your workout tells you to do 3 sets of 10 biceps curls, you need to be picking a weight that you can MAYBE squeeze out 11 or 12.  If you get done with the set and could have easily done 15, 16, or 17 reps, you’re not going to build your skinny arms.  Bump the weight up for the next round and get closer to technical failure.

Progressive Overload Is Your Friend

Use progressive overload to overcome skinny arms

Progressive overload means you are going to constantly be putting new stress on your body through more reps, sets, better form, slower reps, and/or better form.

If you never increase the weight on an exercise, you’re going to eventually hit a wall and you’ll stop seeing progress.

Let’s do another example with the 3 sets of 10 bicep curls.

  • Week 1 you do 3 sets of 10 at 50 pounds.
  • Week 2 you go up in weight and are able to do 1 set of 10 at 60, and then 2 sets of 8 at 60 because you reached technical failure.
  • Week 3 you crank out 2 sets of 10 at 60 and 1 set of 9 at 60.
  • Week 4 you are able to do all 3 sets at 60 pounds.

That’s progressive overload!  When you combine progressive overload with training close to failure, your skinny arms will start to grow!

Get Extra Volume If You're Skinny And Want To Grow Your Arms

Ideally you will do 8 - 10 hard sets for your biceps and triceps at least twice a week.  Depending on your current experience, you may be able to handle more or slightly less sets.

  • If you’re new to the gym, one day will be enough.
  • Already casually working out?  Add that second day.
  • Advanced lifters can add a third day to get the ball moving with skinny arms.

Additionally, ensure that you are picking exercises that directly work your arms.  You’ll benefit from big compound exercises like bench press and chin-ups since they work your arms, but adding in the direct work will put the volume in the right place and your arms will grow.

Get Bigger Arms By Doing Both Compound & Isolation Exercises

Another tip for learning how to get bigger arms is to not only focus on specific exercises for your biceps and triceps.

Those are great and should definitely be utilized every upper body day, but you also want to have a mix of compound exercises.

Big lifts like variations of bench press, rows, push-ups and pull-ups will help add size to your skinny arms.

Here are my favorite articles of each:

The Best Dumbbell Chest Press Variations

Dumbbell Row Variations

How To Do Your First Chin-Up

Fun, Unique, & Challenging Push-Up Variations

How Many Sets And Reps Of Bench Press You Should Do To Build Muscle

Use A Variety Of Equipment

The specific isolation exercises to pair with your compound lifts can come from a variety of equipment.

When growing skinny arms, it’s possible to see some growth from bands, but the real growth will come from barbells, dumbbells, machines, and cables.

Here are a few of my favorite specific arm exercises to help grow scrawny arms!

Barbell Bicep Curls

You can’t go wrong with the classic barbell bicep curls.  Perform this exercise with control and remember to take 2 - 3 seconds lowering the weight!

If you don’t have access to a barbell, it’s totally fine to use dumbbells with an underhand grip.

Hammer Curls

By using a pair of dumbbells in neutral grip position and lifting the weight, you are going to be targeting the brachialis muscle in your biceps.  This will give more fullness to the side of your arm, while the barbell bicep curl with target the peak muscle that most people associate with biceps.

Dumbbell Smash Spider Curls

This is my current favorite bicep curl exercise so I figured I would throw it in to help build your skinny arms!

It involves you hanging off the bench so it’s somewhat mimicking a preacher curl where you can isolate your biceps.  I enjoy the added element of having to keep the dumbbells squeezed together which will target the brachialis like the hammer curl does.

Want more bicep curl variations? You’re in luck!  Here are my 15 favorite bicep curl variations.

Rope Pushdowns

Using the cable machine for cable rope pushdowns will help build the long head of your tricep, which is the longest muscle.  This is what helps give you the horseshoe look on the back of your arms.

Always pick a weight that allows you to lock your arms out on each rep versus doing half reps because it’s too heavy.


Another exercise that will target the long head of the triceps are dips!

These are challenging so use bands or the assisted dip machine if you need to.  The added benefit of doing dips is that it’s a compound exercise so you’ll also be building muscle in your chest and shoulders.

Dumbbell Skullcrushers

To target the other parts of your triceps, add dumbbell skull crushers into your routine.  Similar to the barbell bicep curl, you can do these with a barbell or dumbbell.  

I enjoy an extended version of this exercise versus having the dumbbell straight above my face.  Give it a try!

Sick Of Skinny Arms? Eat More!

As mentioned earlier, the optimal way to build muscle is by eating in a calorie surplus.  

If you’re not eating enough and are at maintenance or a calorie deficit, your arms will not grow as fast.

  • Optimal calories for bigger arms: multiply bodyweight (in pounds) by 16 - 20
  • Optimal protein for bigger arms: Eat at least 0.7 grams of protein per pound of bodyweight 

If you’re an ectomorph and want to gain weight and build bigger arms, check out The Complete Guide On Ectomorph Weight Gain.  You’ll get a full workout along with more information about how you should be eating.  For a specific meal plan, check out Bulking Diet For Skinny Guys

Workout Program For Skinny Arms

Now that you know what it takes to build muscle in scrawny arms, I want to provide you with add-on volume workouts to do on top of your current program.

Do 2 - 3 of these routines on top of your current training to get extra arm volume into your workouts.  These can be added at the end of a leg day workout or added into your upper body days, or down as a stand alone quick workout.

If you need a full workout program, check the The Complete Guide On Ectomorph Muscle Building for a 3x/week program.


Workout A:

Barbell Bicep Curls: 3 x 8 - 10

Barbell Skullcrushers: 3 x 8 - 10

Dips: 3 x 8 - 10


Workout B:

Rope Hammer Curls: 3 x 10 - 12

Rope Tricep Pushdowns: 3 x 10 - 12

Dumbbell Spider Smash Curls: 3 x 10 - 12


Workout C:

Alternating Dumbbell Bicep Curls: 3 x 8 - 10/side

Dumbbell Skullcrushers: 3 x 10 - 12

Straight Bar Pushdowns: 3 x 15

Skinny Arms Development Recap

To pull everything all together, remember that genetics play a role in the size of your arms.  Don’t let that deter you from building muscle though.  There are plenty of things you can do to combat why your arms are so skinny including:

  • Eating enough calories and protein
  • Implementing progressive overload
  • Training close to failure
  • Having a balance of compound exercises and isolation exercises
  • Training with good form and controlling the weight on each rep
  • Getting enough volume in on your arms each week