Why Are My Arms So Skinny? 6 Authentic Tips for Gaining Muscle

If you’re one of those guys (or gals) who stares at the mirror and wonders why your arms are so small, I can relate.

It’s like no matter how hard you try to increase your arm size, they stay skinny. Maybe it’s genetics or you’re working out wrong, but nothing seems to fix it.

Why are my arms so skinny? Your arms are skinny because you have a slender physique. They’re longer than other parts of your body, so they look even smaller. Not to mention the muscles in arms are disproportionately smaller. But, you can add bulk with the right workouts.

I promise you that I can help solve your self-esteem issues.

But, you have to promise me to not let unhealthy thoughts about yourself take over to the extent where your health takes a turn for the worst.

In this article, I’ll discuss the following:

• Why your arms are skinny (for guys and gals)
• What a skinny arm is classified as
• How you can fatten up your arms so they’re in proportion with the rest of your body
• How to build muscle and add bulk to your arms

Let’s get started!

Why Are My Arms So Skinny and Weak (for Men)?

Typically, this is just a card you’re dealt with at birth.

But, that doesn’t mean you can’t overcome it.

If you have skinny arms, then one of the following applies to you:

1. You’re not eating enough food (and what you’re eating is wrong)
2. You don’t know what the right exercises are (and have been doing the wrong ones)
3. You’re not lifting enough weight or mass to grow them in size
4. You’ve hit a plateau and growth at this point will be minimal
5. Muscle growth requires recovery time and you haven’t allotted for it
6. You have expectations beyond what you can realistically attain

I’ll touch upon these later in the article, but you need to do a quick self-evaluation and see what you need to improve on.

As much as you WANT to believe that there’s some crazy external factor at play, your arms could be skinny because you simply don’t know better.

That’s okay!

I’ll help you change your approach.

1. You’re Not Eating Enough Food (and What You’re Eating is Wrong)

The likely culprit for your arms not gaining in size is that you’re not eating enough.

If you consume too many calories and don’t work it off, then you gain weight. But, if you don’t consume extra calories, then you won’t be able to build muscle.

There’s a fine line between fattening up and bulking up.

You want to do the latter.

Here are some interesting dietary factoids:

• Research published in Medicine and Science in Sports and Exercise suggests that athletes should consume 1.6 to 1.7 grams of protein per kilogram of body weight (roughly 2 pounds) to bulk up
• According to the New England Journal of Medicine, whenever a sedentary person gains 3 pounds (1.4 kilograms), approximately 1 pound (0.5 kilograms) is lean muscle mass

My point is that you need to reconsider your approach to your diet if you want to build lean muscle mass.

Another thing you can do is the Mifflin-St Jeor equation, which calculates your basal metabolic rate (BMR). It was developed in the 1990s.

Here’s the equation for both men and women:

• Men: (4.536 x weight in pounds) + (15.88 x height in inches) – (5 x age) + 5
• Women: (4.536 x weight in pounds) + (15.88 x height in inches) – (5 x age) – 161

That formula will tell you the base number of calories you need to maintain your current weight.

Hint…

It may not be 2,000.

2. You Don’t Know What the Right Exercises Are

Isolation exercises are not the best for improving your skinny arms. You won’t experience quicker success just by targeting a muscle group.

While it’s helpful to do some isolation exercises to improve specific parts (like subtle differences between arms), you should focus on compound exercises.

Compound exercises target multiple muscle groups at once.

Some of them include:

• Dips
• Bench presses
• Overhead shoulder presses
• Deadlift squats

Compound exercises should give you quicker results than isolation exercises, plus you get to work out other body parts simultaneously.

I’ll go over some specific isolation exercises later in the article in case that’s what you need help with right now.

3. You’re Not Lifting Enough Weight or Mass

Even if you’re doing the right exercises, there’s a strong chance that you’re not lifting enough weight to make a tangible, discernible difference in your muscle mass.

A common methodology is to lift as much weight as you can while maintaining the right form. Over time, that figure will increase (and so should your muscle size).

If you’re not zapped out after 10+ repetitions, chances are that you’re not lifting enough weight.

During your first few months of training, it’s advisable to add 5 extra pounds every two weeks.

4. You’ve Hit a Plateau in Growth

This may suck to hear if you’ve been at this for a while, but beginners often get quicker gains. If you’re new, then you’re in luck.

The important part is not to give if you’ve hit a plateau.

Some tactics to get out of it include:

• Vary up your exercise routines
• Up the intensity (or try HIIT)
• Switch up the order for how you work out

It’s kind of like working late at night and needing an extra caffeine boost just to make it through. Otherwise, you’ll never survive.

5. Muscle Growth Requires Recovery Time

You should take rest days seriously if you aren’t already.

When you build muscles, you’re tearing down the existing muscle fibers and waiting for them to grow back even stronger.

If you don’t rest and allow them to grow back, you won’t be gaining any muscle mass.

In her best-selling book Good to Go, runner Christie Aschwanden says that muscle pain can peak 24 to 72 hours after a hard workout.

So, give yourself time to rest and your body will thank you. ESPECIALLY if you’re a beginner.

6. Your Expectations Aren’t Realistic

I’m sorry to be the potential bearer of bad news, but some guys have these incredibly unrealistic notions of how they want or think their bodies should look.

Not everyone gets to look like the model in a fitness magazine or the Hollywood actor playing a superhero.

(Or, 50 Shades of Grey if you swing that way. I totally do!)

The simple truth is that people overestimate how quickly they can grow muscle, just like they wrongly predict how long it will take to lose weight.

If you’re lucky, you can expect to gain 1 to 2 pounds (0.5 to 0.9 kilograms) of lean muscle mass per month.

So, it may take upwards of 6 months, in some cases, to gain an extra inch on your biceps.

All About Skinny Arms

You probably have questions about skinny arms and I wouldn’t be surprised in the slightest about that.

Here are some that I thought of in advance:

1. What is considered a skinny arm?
2. Can skinny arms get big?
3. How can I fatten up my arms?
4. Why are my arms so skinny but I’m fat?
5. Why are my arms so skinny compared to the rest of my body?

These may all sound like variations on the same question, but they’re each valid in their own right.

Since everyone’s body is different, there may be a different explanation from guy to guy even if you look the same from the outside.

If you have more questions after these, drop them in the comments below.

1. What is Considered a Skinny Arm?

Here’s the deal…

What classifies as a skinny arm is probably NOT what you think.

Here’s a simple table that breaks down arm size in relation to BMI.

Arm Size in Relation to BMI

The problem with using BMI as your barometer is that BMI just accounts for weight. It doesn’t go into what the breakdown of muscle to fat is in your body.

You could have big arms purely because you’re overweight or you could have big arms with bulging biceps.

So, you have to dismiss the idea that there is a right and wrong arm size.

I see these kinds of questions all the time:

• Are 17-inch arms considered big?
• Is 15-inch arms big?
• Are 11-inch biceps big?
• Are 14.5-inch arms big?
• Is a 16-inch bicep big?
• Are 13-inch forearms big?
• Is 11-inch arms small?

There just isn’t a right and wrong answer for these.

A 17-inch arm on a guy who weighs 120 pounds would look cartoonish but on a guy who’s 6′ 2″ and 200 pounds, it wouldn’t look out of place.

You need to figure out a healthy goal for your arm size to be so you can work towards attaining it, but there is NO magic number.

2. Can Skinny Arms Get Big?

Absolutely!

But, here’s the deal. As I mentioned, you need to have realistic expectations.

You may never have massive arms and biceps bulging through your t-shirt.

With hard work, though, you can easily expect to add 1 to 2 inches (2.5 to 5.1 cm) of circumference to your arms with the right workout and diet regime.

Having an unhealthy version of your ideal physique in your head can be damaging to your mental health and cause you to overwork your body physically.

3. How Can I Fatten Up My Arms?

To fatten up your arms, the first thing you need to look at is your diet.

Are you consuming enough calories so that you can build muscle?

If not, start with that.

Here are some exercises to try out on top of improving your diet:

• Arm slides
• Ball slams
• Dumbbell bench press
• Narrow push-ups
• Bicep curls

Let me know how those work out for you.

4. Why Are My Arms So Skinny But I’m Fat?

There are many different ways to explain body types, but here’s the one I think is the best for this article.

There are three types:

• Skinny on skinny: your entire body is skinny
• Fat on fat: you’re more overweight than the next guy
• Skinny fat: you have skinny legs and arms, but a protruding belly (AKA dad bod)

If you’ve got skinny arms but you’re heavier in other areas, it’s probably a sign that you’re skinny fat.

While it’s not ideal to just be fat in one area, you can work to fix this. And, once you get your belly fat down, your arms should look bigger just from better proportions.

Here’s what you need to do depending on your body type above to gain muscle mass in your arms:

• Skinny on skinny: up your protein and carbohydrates so you are consuming enough calories to turn into muscle
• Fat on fat: cut your calories by 1/4 to 1/2 (depending on how overweight you are), up your protein intake, and cut out as many types of processed and refined sugars as possible
• Skinny fat: cut sugar, alcohol, and carbs and increase your protein intake

Let me know in the comments below if this doesn’t make any sense.

5. Why Are My Arms So Skinny Compared to the Rest of My Body?

I mentioned the different body types above, but what I didn’t mention is that having skinny arms can be entirely up to your physique.

Just like people skip leg day and end up looking like a t-rex, you can skip (or neglect) arm day and have your arms be skinnier in proportion to the rest. Or, you’ve been working out your arms the wrong way.

You just need to figure out which it is.

Are you confident you know how to work out your arms? Or, have you been secretly hoping your arms get bigger through a puberty no one else your age is getting?

Be honest with yourself and get back to me.

Why Are My Arms So Skinny (for Girls)?

Just like with guys, females can have skinny arms, too. And, the reasons for them are practically the same.

I’ll copy them here for your convenience:

1. You’re not eating enough food (and what you are eating is wrong)
2. You don’t know what the right exercises are (and have been doing the wrong ones)
3. You’re not lifting enough weight or mass to grow them in size
4. You’ve hit a plateau and growth at this point will be minimal
5. Muscle growth requires recovery time and you haven’t allotted for it
6. You have expectations beyond what you can realistically attain

Many women complain about their arms being too big (having bat wings), so if your arms are too small, then you’re in the minority.

But, that doesn’t mean you can’t feel better about yourself and your physique.

Just know that it’s going to be harder to bulk up and gain muscle as a female. Women have to work harder at it than men to see the same results.

How to Get Fat on Your Skinny Arms

If you’re a skinny woman, it’s totally possible to get fat on your arms.

A lot of women have this very tangible fear that if they work out or exercise too much, they’ll become the she-hulk and never look attractive to a man (or woman) ever gain.

While that fear feels real, I promise it’s irrational.

Here are some steps you can take to build muscle on your arms as a woman:

1. Eat up
2. Lift heavier weights
3. Use compound movements that focus on multiple muscle groups instead of isolation exercises
4. Do more cardio and at higher intensities

I know some of these may contradict what you’ve read in magazines or on the internet, but I promise they won’t turn you into a hideous version of yourself you can’t look at.

If you’ve struggled with putting weight on before, then you also shouldn’t rule out a genetic condition that prevents you from gaining weight.

Consult a doctor if you think there’s reason for concern.

How to Bulk Up Your Arms the Right Way

I mentioned before that a reason why your arms might still be skinny is because you haven’t been working them out correctly.

No worries!

When it comes to growing biceps, it’s easiest to break down the specifics in three sections:

1. Types of weights and resistance
2. Different grips
3. Exercises to try

Here are the common types of weights and resistance:

• Dumbbells
• Barbells
• Cable machines
• Resistance bands

Here are the different grips to try out:

• Underhand: with your palms facing up
• Hammer: with your palms toward the midline of your body
• Overhand: with your palms facing toward the ground
• Twist: rotating your wrist and changing your grip as you move the weight

I mentioned these before, but here are some exercises for you to try out:

• Arm slides
• Ball slams
• Dumbbell bench press
• Narrow push-ups
• Bicep curls

I hope you feel more confident about working out your arms!

How Long Does it Take to Gain an Inch on Arms?

Not overnight, in case that’s the answer you were looking (and hoping and praying) for.

To gain an inch on your arms, you need to gain about 15 to 20 pounds (7 to 9 kilograms) of lean muscle. Most people can only put on 1 to 2 pounds (0.5 to 0.9 kilograms) of lean muscle mass a month. If you’re a beginner, adding an extra inch may take upward of 6 months.

That being said, it could take more than a year, based on other factors like genetics and diet.

You also need to remember that it’s easier to go from an 11-inch bicep to a 12-inch bicep than it is to go from a 14-inch bicep to a 15-inch bicep.

The bigger you want to go, the harder it is to get there.

Conclusion

I hope you feel more confident about showing your skinny arms who’s boss!

In this article, I went over why your arms might be so skinny. In case you scrolled past it, here it is again for your convenience.

Your arms are skinny because you have a slender physique. They’re longer than other parts of your body, so they look even smaller. Not to mention the muscles in arms are disproportionately smaller. But, you can add bulk with the right workouts.

I also went over the following:

• Why your arms are skinny (for guys and gals)
• What a skinny arm is classified as
• How you can fatten up your arms so they’re in proportion with the rest of your body
• How to build muscle and add bulk to your arms

Do you have any more questions about building bulk in your arms? Drop your questions in the comments below and keep me up to date on your physical transformations.

To your muscle-building success!