When looking to get rid of skinny arms, you first need to determine if you are training arms enough, doing the exercises properly, and if you are providing your body with enough calories to fuel muscle growth.
Getting rid of skinny arms entails training the muscles directly 3-4 times per week. The key is to train both biceps and triceps and use heavy, moderate, and light weights throughout the week to increase strength, size, and vascularity. It’s also important to train the arms using a full range of motion with good form.
Below, we will discuss both the reasons why you have skinny arms and how to fix it in order to build some serious muscle in the biceps and triceps.
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Why Are Your Arms Skinny? (8 Reasons)
Below are eight reasons why you have skinny arms. For most people, there will not be just one reason, but rather a few that often connect with one another in some way. The vast majority of them come from your training, technique doing exercises, and workout programming.
Not Enough Direct Arm Training Volume
This is probably one of the main reasons you are not growing your arms. To effectively grow a muscle, increasing training volume is often one of the first things to do to produce a significant effect.
To grow the biceps and triceps, you need to train them at least twice per week, with each sesion being 8-12 sets (2-3 exercises usually, with each set only counting if it was taken to failure within the rep range).
If you are doing that already, then add another arm day, and train each muscle group directly 3 days a week, or even, 4 days.
There is a point where if you are training more than 25-30 total sets per week of direct bicep and triceps work (25-30 sets, each take to failure within rep range), then your form, or training intensity is often the issue.
I would also make sure to not train the muscle with more than 12-15 total sets per workout, as anymore than this is just extra work that often ends up being “tough” but not productive.
You Are Training Arms Too Heavy
If you are training with a weight that doesn’t allow you to get five, slow and controlled reps before failing, chances are you are training too heavy.
The key to muscle growth is not to lift as heavy as you can (or to lift too light either), but rather to lift heavier weights for a moderate amount of reps some days, and moderate weights for a ton of reps another.
Very rarely do you lift super heavy weights or super light weights when looking to build bigger arms.
As a general rule of thumb, your “heavy” arm workouts should have you train within the 5-10 rep range, with each set taken close to failure.
You Are Training Arms Too Light
If you don’t have the issue of lifting too heavy, then you most likely train too light. Too often people will think they can get away building massive arms with super light weights. And while that isn’t impossible, it just isn’t the most effective way to do so.
If you are using a weight and can get more that 25 reps if you were to train to full failure, then the weight is too light, even on “light” arm days.
The lighter a weight is, the more reps you need to do, and the more true muscle failure you need to achieve.
This is why even bodyweight training can start to lose its appeal for building bigger muscles in more trained lifters because the external load is just too light, even if they did 30+ reps.
If your workout calls for higher rep work, then choose a weight that is the heaviest amount you can lift while still training in the prescribed rep range. If you can do more reps than the rep range prescribed, then the weight is too light.
You Aren’t Training Arm Hard Enough
It is tough when someone tells you that you just aren’t training hard enough, but the truth is most people don’t. When it comes to muscle building, and getting the best results, most people don’t push themselves hard enough to build muscle (or at least build muscle as effectively as possible).
This isn’t to say you need to crush yourself every workout, but it does mean that if you finish a set and could have done more than 3 reps with good form (let’s assume your life depends on it), then you most likely didn’t train hard enough (could have done more reps), or heavy enough (if you were going to exceed your rep range).
Your Aren’t Training in the Full Range of Motion
Full range of motion means that you do bicep curls where you go all the way down to the elbows being fully straight, and do tricep pushdowns and extensions so that your elbows lock out every rep.
So many lifters do half reps, ¾ reps, or just bad reps in general for the sake of lifting more weight, or sometimes just because they were taught wrong.
The biceps and triceps work exclusively at the elbow joint. The bicep flexes the elbow, and the triceps extends the elbow. When doing an exercise, make sure that you have the elbow go into full flexion and extension, under load, with control, for maximal muscle tension.
You Have Bad Form and Can’t Isolate the Muscle Properly
Proper form usually means you are training in the full range of motion, not using momentum to lift the weight, and controlling the load at all times (even when lowering).
When resistance training, the goal is to keep tension on the muscle at all times, and to make the muscle work without any rest to beat it up and break it down so that it rebuilds itself stronger and bigger.
If you are someone who is swinging weights around, speeding through reps, or not focusing on FEELING the muscle work (in this case the biceps and triceps), you need to slow down, use more weight (or lighter if you cannot slow down some) and focus on the muscle.
It takes mental effort to feel a muscle in the beginning, so dedicate the time, learn the skill, and reap the rewards later.
You Aren’t Controlling the Eccentric Phase
When you perform a repetition, there is often a phase where you are actively working to move the weight, and a phase where the weight is stretching the muscle.
For example, in a bicep curl, the phase where you curl the weight up is called the concentric phase. This is often the main phase people think about when they workout. As you lower the weight, the muscle works eccentrically, which has been shown (eccentric muscle contraction) to be one of the main factors to stimulate muscle breakdown and rebuilding.
If you are doing everything to this point, and not having good results, then you may be doing a poor job of controlling the lowering phase. You should control the eccentric phase for 2-3 seconds, sometimes longer (4-6 seconds) to maximize muscle growth.
You Aren’t Eating Enough
If at this point you are doing literally all the above things perfectly, and still cannot gain arm size, then there may be an issue where you are not eating enough to support new muscle growth.
Building muscle requires that you have raw material (calories) to turn into muscle. For some people who have issues gaining size and muscle, this is simply because they are not eating enough food. This is also a tough one to swallow, as you probably feel like you’re eating enough food yet still can’t gain weight.
If this is the case, then the cold hard truth is you simply are still not eating enough. Eating a ton of food one day, and then another, and then for the next 2-3 days you forget to eat a bunch won’t cut it.
For best results, if you suspect your diet is the main reason you can’t gain arm size (really only an issue for people doing everything else right and those who are often very lean and skinny), you need to eat more. Get on a bulking plan, train a bunch, and start building muscle.
Related Article: What Should Your Macros & Calories Be When Bulking?
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9 Tips For Getting Rid of Skinny Arms
Below are nine of the best tips to get rid of skinny arms. If you do these nine things, and do them well, you will grow bigger arms within 8-12 weeks of dedicated and consistent training (not missing workouts and trying hard in every single session).
Train Arms 3-4 Times a Week
Increasing your training frequency (training more days per week) will allow you to increase your overall training volume. If you usually do one workout per week, do two. If you usually do two, do three.
If however, you are already training arms 3-4 days per week, then you should focus on the other tips rather than increasing training arms 5+ days a week.
Train to Failure in the 5-8 Rep Range
As discussed above, the biceps and triceps are muscles, and can respond to a variety of loads. If you are not training in the 5-10 rep range with heavier weights, then you are missing out. The key to training heavy with arms is that you never allow yourself to “cheat” reps, use momentum, or do half reps.
Training heavy with arms with good form often means still lighter than what you “could do” if you let your back, shoulders, or other muscles into the moment, however it also means that you should rarely be able to lift the load with good form for more than 10 reps.
Train arms heavy 1-2 times a week.
Train to Failure in the 8-15 Rep Range
When looking to increase muscle mass and size, this rep range may be the one that offers the most bang for your buck. By lifting in this rep range, you allow yourself the opportunity to train with heavier loads, and high volumes, a potent combination to fuel serious muscle growth.
Training in this rep range also allows you to perform enough muscular work to increase muscle fiber size, strength, and get a huge muscle pump.
Generally speaking, 50% of your arm training should be allocated to this rep range, with the other 50% split between 5-8 reps (25%) and 15-25 reps (25%). All sets should be taken to failure or very close to it (no more than 2-3 good reps left in the tank).
Train to Failure in the 15-25 Rep Range
This last high rep range is a nasty one when done properly.
Most people will train in the high rep range with light weights, and get decent results, however to truly be effective and maximize muscle growth and the pump, you need to use very challenging weights and train in this high rep range to failure.
You are training to failure in this rep range, with the most amount of weight you can use while still performing good reps.
For example, if you choose some weights, and do sets of 20-25 reps, and at the end of the set you could have done 5 more reps with that weight, then odds are the weight was too light.
There is something called the stimulus to figure ratio, and it comes into play when you are lifting very heavy and low reps, or very light and high reps.
Basically, there is an inverse relationship, where when you lift super light weights, you need to do a ton of reps (25+) to get a significant muscle growth stimulus. At some point, doing high reps becomes more and more fatiguing and the stimulus diminished because you just get generally tired.
This is not the ideal situation, as you want to have the muscle give out before your energy levels, focus, and motivation. Therefore, choosing a weight that is still very challenging, to where at the end you struggle to stay within the higher rep range, is key.
Incorporate Drop Sets, Extended Sets, and Supersets
This is a great way to add some extra intensity to your workouts without needing to add a ton of extra sets and training time.
Drop sets are where you perform your set, then immediately drop the weight by 10-20% and do more reps to failure. This is a great way to finish off a muscle, or to add some extra intensity and volume to your workouts.
The key here is to not pace yourself on the first main set, and try to survive on the drop set.
Too often people know they are doing a drop set, and pace themselves or try to save “energy” for the drop set. This is why personally I am still a fan of doing straight work sets with the utmost intensity, and using drop sets occasionally.
Train Every Rep Range Every Week (Different Workouts)
As discussed above, there are three main rep ranges, each providing benefits of their own. If you are only training in one, or two of them, you could be missing out on building more strength and size (5-8 rep range), or increasing blood flow and muscle size (15-25 rep range).
In a well designed program, you would train each rep range, every week, in different sessions (ideally three times a week, or more). You want to start the week training in the heavier rep range when most fresh, then train with moderate to higher rep ranges as the week progresses and your muscles are more fatigued and recovering.
Focus on Isolation and Single Joint Movements
Compound exercises are a great way to build muscle, however if you are looking to attack the arms doing chin ups and dips may not be enough. Often, the larger muscles, such as the back, chest, and shoulders take on the blunt of work when it comes to compound lifts, lift pull ups, chin ups, and presses.
While you should still do those exercises because they offer many other benefits (and still increase arm strength), you want to take a more isolated approach to building bigger arms by including isolation exercises like curls, pushdowns, overhead extensions, and any movement that has only the elbow flexing and extending.
When you focus on isolation and single joint movements (exercises that only allow the elbow to move through a full range of motion) you remove the ability to use the bigger muscles to assist in the movement (or take over the movement). Anytime you allow the shoulders to move in an exercise you automatically decrease the direct stress on the biceps and triceps.
Use Machines and Cables to Train to Failure
The nice thing about machines and cables is that they allow you to train to failure and often do so by restricting your ability to use too much momentum or bad form (machines are better for this). When training hard and to failure, it can be tough to lock yourself in and make sure you are not letting your body move around and swing the weight around to lift it.
We have all seen those lifters who flail their body and the weights around it “get a few more reps”. Those sloppy reps do very little to actually build muscle, and can actually do more harm than good.
This is why using machines and cables to force better lifting and form is often a go when it comes to pushing to failure. Removing the ability to use bad form often means better reps, more isolated bicep and tricep workouts, and less injury.
Consume More Calories than You Burn
If you are doing everything else, and still are having issues, then you most likely need to eat more food to fuel muscle growth.
This is usually an issue with people who are thin or lean (under 10-13% body fat), and have issues gaining muscle and weight. If this is the case, start increasing your calories. You can learn more about how to increase your calories for muscle building in this article.
It is important to note that if you are someone who has body fat and isn’t lean (under 13% or so), then there is a good chance you are eating enough to gain muscle, and relisitaly need to revisit the above tips because one or more of these are not being done (despite what you are thinking).
If you are still scratching your head, take a look below at this sample 3-day workout program for arms.
Need a workout program? Get 3 free workouts on Fitbod right now.
Sample 3-Day Workout Program to Get Rid of Skinny Arms
Below is a sample workout program that can be done by any level lift to gain serious arm size. It can be done in conjunction with other exercise for other body parts, and can often be worked into your current routine.
I will typically do day 1 with my first lower body workout of the week, and day 3 with my second lower body workout of the week. Day 2 is a good workout to do on its own, or to throw in with other upper body exercises (assuming you are working out 4-5 days a week).
Day 1 – ‘Heavy” Arm Day
- Preacher Curl: 4 sets of 5-8 reps
- Seated Dumbbell Hammer Curl: 4 sets of 5-8 reps
- Weighted Dip: 4 sets of 5-8 reps
- Close Grip Bench Press: 4 sets of 5-8 reps
Day 2 – “Medium” Arm Day
- Cable Straight Bar Bicep Curl: 4 sets of 8-15 reps
- Machine Preacher Curl: 4 sets of 8-15 reps
- Skullcrusher: 4 sets of 8-15 reps
- Cable Triceps Pushdown: 4 sets of 8-15 reps4 sets of 5-8 reps
Day 3 – “Light” Arm Day
- Machine Preacher Curl: 4 sets of 15-25 reps
- Cable Rope Hammer Curl OR Reverse Curl: 4 sets of 15-25 reps
- Reverse Grip Cable Pushdown: 4 sets of 15-25 reps
- Triceps Cable Kickback: 4 sets of 15-25 reps
If you are still left scratching you head, check out the Fitbod app, and try out 3 free arm workouts to help you build serious muscle in as little as 8-12 weeks!
About The Author
Mike holds a Master’s in Exercise Physiology and a Bachelor’s in Exercise Science. He’s a Certified Strength and Conditioning Specialist (CSCS), USA Weightlifting Advanced Coach, and has over 10+ years of experience working with collegiate athletes, national level lifters, and beginners alike. Mike is Founder of J2FIT Strength and Conditioning, a growing global training company with gyms in New York City, Cincinnati, and online offering personal training, online custom coaching programs.