How Can Skinny Guys Get Big Arms (3 Simple Tips)

For a lot of first time gym goers the aim is usually to get bigger beach muscles with the chest and biceps taking priority. In the start it’s chest and arms day everyday. 

After a while you learn that it’s more beneficial to build a well rounded physique and sooner or later you start to even have a leg day. For many it’s quite easy to build muscle depending on your frame and genetics however there are those select few destined to grind out every pound of lean muscle or inch gained to a body part. 

These people are the skinny guys, if you are one of these guys then it’s not that you look like you don’t workout, it’s that you look like you need to workout! The biggest issue of all is just how can skinny guys get big arms?

I’m 6’1 and when I first started working out my arms looked like this:


Therefore I know just how hard it can be to put some size on your arms, the longer and skinnier your arms are the harder it is to pack on size, especially any sort of noticeable size. 

One of the key issues however is just a lack of general knowledge about how a skinny guy can go about getting bigger arms. There’s a lot of information out there but honestly following a bodybuilders routine of 3 sets x 8 reps of bicep curls is not going to move the needle for you. 

Skinny guys need to approach training differently, there are certain basic and simple things that you can be doing to start to pack some size onto your arms and in this article I’ll cover these easy to implement (though not so easy to follow through with) techniques and basics. 

How can skinny guys get big arms? For a skinny guy to get big arms you need to get stronger in multi joint compound exercises, increase your overall lean body mass by eating in a caloric surplus and finally target all heads of the biceps and triceps for maximum stimulation and growth.

How Can Skinny Guys Get Big Arms

If you’ve been training for any length of time and are struggling to get bigger arms then you need to check three simple questions and make sure you can answer them with yes, these are:

  • Are you increasing total lean muscle mass and bodyweight?
  • Are you getting stronger in heavy compound exercises?
  • Are you targeting all heads of the muscle group for the biceps and triceps?

These are very basic questions and for some of them you might be wondering what they have to do with getting bigger arms, especially considering the last point is the only one that specifically mentions the arms. 

Everyone builds muscle in the same process biologically however as a skinny guy you will need to do things differently. Endless sets of bicep curls are not going to add any inches to your arms and that is why you need to focus on the points above. 

Increase Lean Muscle Mass (Eat Big)

The first thing you need to be looking into when trying to build bigger arms is not the optimal training program but your diet. Training stimulates the muscle causing microscopic tears to then rebuild and also triggers the hormonal muscle building process of protein synthesis. 

If however you are not covering your basic caloric needs then it is going to be very difficult to build any muscle as all. In order to build muscle you need to feed the muscles as a priority. 

Your first step to bigger arms is therefore to go on a dedicated bulking phase. If you are completely new to the gym then a bulking phase requires eating a calorie surplus each day in order to fuel workouts, muscle growth and put on overall body mass (not just muscle but also water retention and glycogen stores in the muscles). 

To do this you need to eat in a caloric surplus which could be anything from 200kcal – 500kcal when starting out to see what you best respond to. If you are new to bulking then I have a few dedicated guides here that I recommend checking out to get you started right away:

Bulking for beginners
Best bulking foods for hardgainers

The human body likes to be balanced, we’ve evolved to have our bodies function in specific ways and therefore the quickest route to getting bigger arms is to increase overall lean muscle mass. It’s said that in order to gain 1 inch to your arms that you need to gain between 10-20lbs of lean muscle mass depending on how advanced you are in training. 

This makes sense when you think about it, it’s almost impossible to see someone with 20 inch arms but weighing 170lbs. Bodybuilders put on enormous size in the offseason in order to grow a particular muscle group. 

You can focus priority on a specific muscle group to accelerate growth but if you want to see noticeable gains to your arms then you will need to get serious about your diet and start putting on size as a whole. 

Get Strong in Compound Exercises

Before you start to focus on any sort of isolation work for the arms you need to start getting stronger in the basic, multi joint, compound exercises. These exercises should be the main focus of your entire routine and it’s not enough to just do them going through the motions, you need to get stronger in them over time. 

The key compound movements that you want to be focusing on are:

  • Deadlift
  • Squat
  • Bench press
  • Horizontal row
  • Overhead press
  • Dip
  • Pullup 
  • Lunge 
  • Loaded carry

These are very basic but very effective exercises for both getting stronger and building overall body mass. Not everyone is suited to each of these exercises depending on your body structure, I personally don’t have the right frame for squatting however getting stronger in the squat has more carryover to an exercise that I am well suited to like a lying hamstring curl. 

You’ll notice that there is no direct arm work here because direct arm work has a lower potential for strength progression. The reason for this is that arm exercises are single joint, often single muscle movements. 

A dip for example will target the chest however also utilize the triceps and front deltoid as a secondary muscle group. Therefore as a beginner being able to dip your body weight (150lb-170lb I’m guessing) will do more for your tricep development than doing a tricep kickback with 15lbs. 

The compound movements also release more growth hormone due to the number of active muscle groups and intensity of the exercise. You might think you are doing a hard set of preacher curls but working up to 400lbs deadlift will humble those opinions.

I am being very direct in my signing of praises for the compound exercises, I know the benefits of direct arm training when it comes to stimulating muscle growth and hypertrophy however this is a secondary focus. 

If you are not getting stronger in the compound lifts then you are leaving so much growth potential untapped, as a skinny guy you really do need to get stronger in order to build muscle and heavy compound exercises are the way to do it.

Make Sure You Target All Heads of the Biceps & Triceps

Finally we can get onto the section of the article that you have surely been waiting for and that is the arm workouts themselves. 

Before I get into it I need to point out that a specific arm day is not required, especially for a beginner. If you are running any sort of push/pull based program of upper/lower split then you only need to add an exercise or two for each muscle group to the respective day. 

If you are pulling then you add 1-2 bicep exercises and if pushing you add 1-2 triceps exercises. As mentioned these act as secondary muscles to the big compound movements so are already being engaged and stimulated during a workout. 

If you are not sure on what split you should be doing then I’ve rounded up the best splits for a beginner here (note that arm specific days are not included in this):

Best workout split for an ectomorph

The important thing to be aware of when training arms is that both the bicep and triceps are made up of multiple heads that perform different functions (hence bi and tri in the names)

Targeting Biceps

The biceps are made of two muscle heads, the bicep long head (outer arm) and bicep short head (inner arm). There is also a muscle that runs underneath the bicep known as the brachialis and a forearm muscle that runs over the elbow joint known as the brachioradialis. 

Whilst not part of the actual biceps brachii muscle working these two muscles with a neutral grip will help to increase overall arm size (every little helps when it comes to building bigger arms as a skinny guy).

The long head and short head of the bicep both have different functions as a muscle group and are fully activated in specific ways. For overall arm development a basic standing barbell or dumbbell curl are not the best exercises for you to focus on.

For the bicep long head you want to target this with your elbows slightly behind your torso in order to work the muscle in the fully lengthened position. Cable curls facing away from the machine and lying incline dumbbell curls are the best exercises for this whilst dumbbell hammer curls also work well. 

For the short head of the bicep you want your arms to be raised in order to work the bicep through a fully shortened and contracted position. The best exercises for this are preacher curls, spider curls and high cable curls. 

The basic barbell or dumbbell curl is good for working the bicep in the mid range however for optimal growth you want to target all heads and end ranges with the exercises listed above. 

Also note that one exercise targeting the short head and one targeting the long head are enough, therefore pick one and get stronger with it over time before switching. 

Targeting Triceps

The triceps are made up of three heads, the lateral head (outer arm), long head (largest portion of inner arm) and the medial head (lower inside of the arm). 

If you want bigger arms it’s good to point out that the triceps make up ⅔ of the overall upper arm, therefore the real key to bigger arms is not endless curls but focusing on growing your triceps. 

To optimally work the triceps you want to follow a similar method to the biceps and try to target all of the heads individually. Triceps will get worked during heavy presses and dips so be careful not to overdo it on these exercises, especially since the elbow joint can be prone to irritation if overworked. 

To work the lateral head you should use exercises with your arms by your side, the best exercises for this is simply the standing tricep cable pressdown or you could also use bench dips. 

To work the long head of the triceps you want to use overhead exercises (this is where many miss out and leave progress on the table), these include overhead tricep extensions, lying skull crushers or French presses.

Finally the medial head of the triceps is best worked with the arms by your side taking an underhand grip, the best exercise for this is a cable tricep pressdown with an underhand grip.


Hopefully you can see that there is more to getting bigger arms than just endless sets of bicep curls. If you really want to pack some size onto your arms then you need to get into a calorie surplus, get stronger in the compound exercises and finally make sure you are targeting all the muscle heads through all the different range of motions.

What Next

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