Do Protein Shakes Help Skinny Guys Gain Weight?

do protein shakes help skinny guys gain weight

Are you a skinny guy dreaming of a beefier body? If you are, then this post will help bring you one step closer to your goals. Because today, I will be answering the question: “do protein shakes help skinny guys gain weight?”.

Consuming protein shakes within manufacturer guidelines is a convenient and cost-effective method to help skinny people increase their caloric and protein intakes. These extra nutrients are turned into muscle and fat, making protein shakes an excellent way for underweight people to gain weight.

2 years ago, I was that skinny guy swamped by the choice of weight gainers at the nutrition store.

But more importantly- I was skeptical about the effectiveness of said weight gainers.

That’s why today, I will be sharing my personal research and experience on the matter, in order to help you make an informed decision.

Are you ready?

Let’s jump right in!

How I used protein shakes to build muscle as a skinny guy.
Protein powders helped me to gain almost 40lbs of lean muscle! Find to how below!

Before I dive in, have a go at choosing your perfect protein shake!

protein shake weight gain decision chart

Why Protein Shakes Can Help Skinny Guys Gain Weight

First, I will give you the short answer to the question:

Yes, protein shakes will help skinny guys gain weight!


Now that’s out the way, I will give you the supporting evidence.

To do so, I will be using two case studies- one personal and one scientific.

Personal Case Study

First, I will be using myself as an example of how protein shakes can help you gain weight.

Now, I’m a biomedical scientist by training. Consequently, I’m very risk-averse when it comes to introducing external substances into my body in general.

So when I first began my weight gain journey, I was set on doing so as naturally as possible (i.e. no protein shakes!).

But I found it frustratingly difficult to gain any significant weight. No matter how much I trained or ate, the scale numbers were increasing at a rate of a growing tree!

So I decided to give protein shakes ago (they are in theory a natural supplement after all).

And here are the results:

protein shakes helped me, a skinny guy, gain weight

As you can see, protein shakes do indeed help a skinny guy gain weight! (and a better dress sense apparently!)

In fact, I managed to bump the scale readings from 130lbs to 145lbs. Most of which was pure lean muscle.

And this was from a single shake per training day for 1 year (combined with weight training of course).

Check out my other article to learn how to train to gain muscle mass!

Scientific Case Study

Secondly, I will share a scientific case study that shows that protein shakes can effectively help skinny guys gain weight.

This 2017 study separated 17 men into two groups:

  • Group 1- consumed a 25g whey protein shake immediately after weight training.
  • Group 2- consumed a placebo shake (no protein) immediately after training.

The protein balance in the 2 groups was then measured 24 hours after exercise.

Just to clarify, protein balance is a measure of muscle gained. And the more muscle gained, the more weight gained!

So what did the scientists find?

Take a look below.

bar chart showing protein shakes can help skinny people gain weight

As you can see, consuming protein shakes increased levels of protein synthesis by almost 57% compared to drinking the placebo shakes!

Therefore, protein shakes can in fact help skinny guys gain weight (it’s not just me!)


Protein shakes are effective at facilitating muscle gains in skinny guys (when combined with weight training). And this will translate into weight gains. I have personally gained weight with protein shakes, and these results have also been backed by the 2017 West et al. study.

How Protein Shakes Help Skinny Guys Gain Weight

So now you may be wondering how exactly do protein shakes help you gain weight?

Well, it comes down to basic maths.

As JC Deen from JCD Fitness explains, gaining weight requires you to consume more calories than you expend. And this is called a caloric surplus.

Furthermore, protein shakes contain calories as well as protein.

So when you consume a shake, you are also increasing the likelihood you will enter a caloric surplus.

protein shakes help skinny guys gain muscle by supplying calories and protein

And when this happens, Joe from 9 To 5 Nutrition explains that your body can either turn those calories into either muscle or fat.

Now- if you are like most people, you will be aiming for the former.

In other words, you will want the extra calories and protein to be turned into muscle in order to gain weight.

And in order to do so, you will have to combine your shakes with a weight training program!

But if you are the minority (want to gain weight by getting fatter), by all means, drink shakes without working out!

Check out my other article to determine how long you should maintain a caloric surplus!


Protein shakes will help you gain weight by increasing your caloric and protein intake. And this in turn increases your likelihood of entering a caloric surplus. When this happens, your body will turn those surplus calories into muscle or fat (depending on how hard you train). And this results in weight gain.

Are Protein Shakes Necessary To Gain Weight?

Next, you are probably wondering if protein shakes are essential to gain weight as a skinny guy.

Now that you understand how protein shakes work, you can probably guess yourself (go on have a go!)

The answer?

No protein shakes are not essential to gaining weight.

But they do help tremendously.

Let me explain.

Protein Shakes Increase Your Calorie And Protein Intake

Not everyone finds it easy to eat a caloric surplus or meet the required amount of protein to gain muscle.

Trust me, I have tried and failed for years during my early weight gain efforts!

And I imagine many of you have also tried and failed just like me.

That’s where protein shakes come in.

FoodCaloriesProtein (g)
Typical Meal400-60015-25
Typical Whey Shake15025
Typical Mass Gainer Shake500-150030-50+
You can check out my other post for homemade mass gainer recipe ideas!

Ramiz Shah from Squat Wolf notes that a typical protein shake can contain anywhere from 150 calories per shake to a massive 1500 calories per shake (some shakes even more!).

Additionally, many shakes can contain anywhere between 25g of protein to over 50g of protein per shake.

And if you have tried eating that many calories and protein in one meal sitting, you will know how difficult that can be.

Therefore, protein shakes can be an extremely convenient way to boost your calorie and protein intake. And this will help you gain weight more easily.

If you’re looking to bulk up fast, you might be interested in my workout for skinny guys to gain muscle with and without equipment.

Protein Shakes Provide Cost-Effective Calories and Protein Compared To Whole Foods

Additionally, protein shakes are usually a much more cost-effective way to hit your calorie and protein targets.

Take a look at my comparison chart below.

I have calculated the average cost per calorie and gram of protein for two common types of protein shakes (mass gainer and whey shakes).

I have also done the same for common muscle-building foods (like steak, chicken, tuna, and tofu).

Here are the results.

FoodAverage Calories (Kcal)Average Protein (g)Average Cost Per Portion (US$)Average Cost Per Calorie (US$)Average Cost Per Gram Protein (US$)
My Protein Mass Gainer Shake500351.820.0040.052
My Protein Whey Shake150250.590.0040.024
8 Oz Steak (227g)553579.000.0160.158
8 Oz Chicken Breast (227g)542613.100.0060.051
8 Oz Tofu (227g)173183.000.0170.167
1 Can Tinned Tuna130251.500.0120.060

As you can see, protein shakes are an extremely cost-effective way to consume calories and protein, when compared with eating whole foods.

In fact, protein shakes offer both a cheaper cost per calorie AND cheaper cost per gram of protein, when compared to other foods.

And food cost is a major factor to consider when you are trying to eat like you are preparing for winter hibernation.

Basically, every cent and penny counts when trying to gain weight.

And protein powders will offer you the best bang for the buck.


Protein shakes are a luxury but not a necessity when trying to gain weight. You can gain weight by eating whole foods by all means. But shakes provide a more convenient way to reach your caloric and protein targets (they are also more cost-effective). And these are both factors that will help you sustain long-term weight gain.

You may also be interested in my other article for some of the cheapest ways to eat protein.

Best Protein Shakes For Skinny Guys To Gain Weight

So what are the protein shakes available to help you gain weight?

If you go to any sports nutrition store or website, you will be stumped. I know this because I have been in the same position before!

There are more brands and types than your eyeballs can physically take in!

But don’t worry.

Because I will now give you a crash course in choosing the right protein shake to gain weight as a skinny guy.

Most shakes will fall into one of these 4 categories:

  1. Mass gainers.
  2. Whey.
  3. Casein.
  4. Blended.
whey/casein/blended shakes have a different weight gain profile than mass gainers

1. Mass Gainer Shakes (My Recommendation For Skinny Guys)

mass gainers help help you gain overall weight

Mass gainers are designed to do what they say- help you gain mass.

They are characterized by a high protein, carbohydrate, and sometimes fat content.(1)

Mass gainers are designed for one thing- to supply your body with a big dose of calories and protein.

This makes mass gainers extremely effective at helping skinny guys bulk up.

As I mentioned before, it’s not uncommon for mass gainer shakes to contain upwards of 1000 calories / 50g protein and more.

And those calories need to go somewhere right?!

However, the ridiculous calories and protein in mass gainers can be both a blessing and a curse.

That’s because the calories also increase the likelihood that you will make fat gains alongside muscle gains. And the risk becomes even higher if you are not weight training intensely on a regular basis.(2)

I recommend the myprotein weight gainer blend for skinny guys to rapidly gain weight and build muscle.

Having used multiple mass gainer brands as a skinny dude, I found the MyProtein Weight Gainer Blend to be one of the cleanest and cheapest ways to rapidly bulk up.

Each serving contains 27g of protein at 365 calories.

I’ve also used the MyVegan Whole Fuel blend, which I highly recommend for vegans and vegetarians.

Each serving contains 30g of protein at 436 calories.

Check out my other article to learn how to gain muscle with minimal fat gains!

2. Whey Protein Shakes (My General Recommendation)

whey is great to increase lean muscle

Whey protein shakes are like the smaller, less obnoxious, brother of the mass gainer shake.

They are made from milk protein and characterized by a high protein content with minimal carbohydrates and fat.

This is why people often call them “clean shakes”.

And this makes whey protein shakes highly effective for gaining lean muscle with minimal fat gains.(3)

Furthermore, whey is a form of fast-digesting protein. This means the body can absorb whey at a rapid rate.

And this makes it ideal to consume post-workout when your muscles are craving nutrition.(4)

For quality peace of mind, you may be interested to know that whey protein is also one of the most well-studied protein supplements.

As such, whey is widely regarded as safe for consumption (assuming you are dairy-tolerant and follow manufacturer use guidelines).(5)

Although whey is effective for gaining lean muscle mass, you will need to combine it with a highly nutritious diet plan in order to gain significant weight.

And this is due to the “clean” profile of whey protein shakes.

I recommend the myprotein impact whey as a general protein powder to build lean muscle afte

These are my favorite types of protein powder for lean gains.

I’ve been using the MyProtein Impact Whey for over 3 years now.

Each serving contains 21g of protein and 100 calories.

If you like, you can also check out my beginner’s guide to gaining your first 10lbs of muscle.

3. Casein Protein Shakes

casein is also great to increase lean muscle

Casein protein shakes are like the slightly lesser well-known, twin-brother, of whey protein.

In many respects, casein is very similar to whey.

They are both dairy proteins, effective for gaining lean muscle weight, and widely accepted to be safe to consume.(6)

The major difference is that whey protein is a slow-digesting protein. This means that the body absorbs it a much slower rate. And this makes casein protein shakes more suitable for post-work and pre-sleep consumption.

By drinking casein after training or before bedtime, you can provide your body with a slow (but constant) release of calories and protein. And this will help you maintain muscle growth.

But just like whey, you will need to combine casein with a nutritious meal plan if you hope to make any significant weight gains.

I’ve used the MyProtein Slow-Release Casein in the past.

Although you get the benefits of a slow-releasing protein, it’s quite a thick shake and not as appetizing as the Impact Whey.

Tired of being skinny? You can check out my other article for 11 tips to gain weight as a skinny person!

4. Blended Protein Shakes

blended shakes are made from casein and whey

If whey and casein were to morph into one super-sibling, then you would get the blended protein shake.

In other words, a blended protein shake contains both whey and casein.

Therefore blended protein shakes offer the best of both worlds.

In fact, this 2006 study showed that drinking a blended protein shake leads to increased muscle gains and decreased fat gains in experienced athletes, when compared with drinking whey alone.

And this has been attributed to a more complete protein-release profile seen in blended shakes.(7)

To put it simply, blended shakes allow the protein to stay in your blood for longer. And this will prolong the duration of protein delivery to your muscles.

Therefore, these blended shakes are a great choice for skinny guys trying to gain weight by adding lean muscle.

I’ve personally found these to be gimmicky more than anything.

They may be great for elite athletes, but for the average skinny beginner, pure whey or casein shakes are sufficient enough to help you build muscle without the extra price tag.


The most popular members of the protein shake family are mass gainer, whey , casein, and blended protein shakes. All of these will help you to gain weight as a skinny guy. Where mass gainer shakes are most effective for general body mass gains, whey/casein/blended shakes are more effective for lean muscle gains.

Which Protein Shake Is Best For Skinny Guys To Gain Weight?

Now you know that protein shakes are effective for gaining weight. And you also know about the 4 most popular protein powders.

But as a skinny guy, which protein shake should YOU choose to gain weight?

It Depends On Your Body Type

It really depends on your current body type.

are you a skinny or skinny fat guy?

Are you currently skinny (<11% body fat across the entire body with very little muscle)?

If so, then you are probably more tolerant to gaining a bit of fat together with muscle.

Or are you more on the skinny-fat side (11-15% body fat with noticeable fat around the mid-section)?

If this is the case, then you are probably less tolerant to gaining fat (since you may already have a slight belly!).

It Also Depends On your Goals

Which protein shake you choose will also depend on your long-term goals.

To put it simply:

  • Choose a mass gainer shake if your goal is to gain weight as fast as possible- opting for this route will see you make large muscle gains (assuming you also follow an intense resistance training program). However, the drawback is that you will also likely gain some fat on the side. If you are very skinny, this will probably not be an issue for you.
  • Choose a whey/casein/blended shake if your goal is to gain lean muscle mass- opting for this route will see you make muscle gains. And these gains will be on the leaner side. This means you are much less likely to store excess fat. However, the drawback to this is that you will have to spend some time creating and following a diet plan that satisfies a caloric surplus. If you are currently skinny-fat, this may be a more suitable option for you.

Take a look back at my decision chart at the beginning of this post. It will help you make an informed choice!


Choose a protein shake according to your current body type and goals. A mass gainer will be more suitable for skinny guys who are looking to generally bulk up fast (and more tolerant to fat gain). Whereas a whey/casein/blend shake will be more suitable for skinny-fat guys who are looking to add lean muscle with minimal fat gains.

You may also be interested in my other post to find out how long it takes a skinny guy to get jacked!


That’s it!

Today I have answered the question- do protein shakes help skinny guys gain weight?

Though not essential, protein shakes are an extremely convenient and cost-effective way to increase your calorie and protein intake. And this makes them a recommended method for gaining weight as a skinny dude

There are many protein shakes on the market, and which one you choose will depend on your current body type and weight-gain goals.

My decision tree should help you make up your decision!

Will you be adding protein shakes to your weight gain plan?

Feel free to send me a message if you have any questions! You can find my details on the “contact us” page.

You may also be interested in the downloadable Kalibre Blueprint PDF which details exactly how I gained 40lbs of lean muscle (it’s 100% free!). It details the exact exercises and nutrition (with printable worksheets) I used to go from skinny to ripped!

Thanks for reading guys!

Peace Out,


(Biochemistry BSc, Biomedical Sciences MSc, Ex-Skinny Guy)


I'm Kal (B.S, M.S)- a health & fitness writer and owner of Kalibre Fitness. I love to nerd out on weight training and nutrition. My primary interests are in muscle hypertrophy mechanisms and strength development. You can connect with me in the "Contact Us" section below!

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