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Why Mass Gainer Makes You Feel Sick (+How To Stop It!)

While mass gainer is an effective supplement, it does come with some side effects.

One of these side effects being nausea.

In this article, we cover why mass gainer can cause nausea and how to stop feeling sick from mass gainer.

Here’s why mass gainer makes you feel sick:

When you consume mass gainer, your stomach is hit with a ton of calories in a short space of time. This puts a lot of stress on your digestive system which can make you feel queasy. Also, mass gainer often includes creatine which can cause nausea in high doses.

Man drinking a mass gainer shake

5 Reasons Why Mass Gainer Makes You Sick

Your Mass Gainer Contains Creatine

Creatine is a natural substance that’s found in red meat and fish. It’s included in many mass gainers thanks to its ability to help you gain more muscle and strength.

But one of the side effects of creatine is that it can make you feel sick.

In one study, 175 patients with the neurodegenerative disease ALS took either 10g of creatine or a placebo over an average period of 310 days. According to the results, 23% of those in the creatine group experienced nausea.

So if your mass gainer contains creatine, then it may be the reason why it’s making you feel sick.

You Drink Your Mass Gainer Too Fast

Some mass gainers taste really bad, and as a result, you’re more likely to chug it down.

But while you may be doing your taste buds a favor, it’s more likely to make you feel sick.


Well, mass gainer is absolutely loaded with calories. For example, MuscleTech Mass Tech Extreme 2000 contains a whopping 2110 calories per serving.

So if you’re chugging down 2110 calories in 5 seconds, your digestive system is going to be overworked. And lots of blood will flow from other parts of your body to your stomach to help digest the mass gainer. This can make you feel queasy.

You Take Mass Gainer Before Your Workout

As we’ve just covered, when you drink mass gainer, lots of blood flows from other body parts to your stomach to help digest the huge number of calories. And this alone can make you feel sick.

But when you exercise on top of this, it can make matters much worse.

Because when you work out, blood flows from other body parts, like your stomach, to your muscles!

So if you work out just after taking mass gainer, you’re going to have a ton of calories sat in your stomach without the blood available to digest it. And this is another reason why mass gainer can make you feel sick.

You Have A Small Appetite

The average mass gainer consumer is someone who’s skinny and has a hard time gaining weight.

One of the main reasons they’re skinny is that they have a small appetite, and as a result, they eat less food than necessary to gain weight.

Now, let’s say you’ve just had a 3-course meal, so you’re full.

In other words, you now have a small appetite.

Well, what do you think would happen if you just tried consuming 2000 calories after a 3-course meal?

You’d feel nauseous, right?!

Well, that’s exactly how it is for skinny people who take mass gainer.

You’re Not Cleaning Your Shaker Properly

When you’ve finished your mass gainer shake, it’s super important to give the shaker a thorough clean with hot water and soap.


Well, many mass gainers contain milk protein, so if the shaker isn’t cleaned properly, then you may consume spoiled milk the next time you drink from it. And drinking spoiled milk is a great way to make yourself sick.

(I’m guilty of this one myself sometimes, so don’t take this personally!)

You Mix Your Mass Gainer With Milk

Many people mix their mass gainer with milk, and for good reason too. It adds even more calories to the shake, and it makes the shake taste better.

But one of the drawbacks of mixing it with milk is that it can make you feel nauseous.

One reason is that it makes the shake a lot thicker, which can cause you to gag and vomit if you have a hard time swallowing it. Also, if you’re lactose intolerant, then consuming milk can make you feel sick.

How To Feel Less Sick From Mass Gainer

Avoid Taking Creatine

If your mass gainer already contains creatine, then unfortunately there’s nothing you can do to remove it. But many people who take mass gainer also take creatine separately.

By doing so, you’re consuming an even higher dose of creatine which is more likely to make you feel sick. So, avoiding creatine is a good idea if you want to reduce sickness from mass gainer.

Drink It Slower

As covered earlier, by gulping mass gainer, you’re going to shock your digestive system by consuming over 2000 calories in such a short space of time.

So, it makes sense then to drink your mass gainer at a much slower pace. By doing so, you’re putting less stress on your digestive system.

How slow? Well, ideally you want to stretch it over the course of half an hour. But if your mass gainer tastes awful, then you could try doing it in less time.

Just don’t come crying back to me if you still feel sick!

Drink It With Water                  

By mixing your mass gainer shake with water, it’ll be much thinner, so it won’t cause you to gag. Also, water is lactose-free, so it won’t make you feel queasy if you’re lactose intolerant.

Take Your Mass Gainer Away From Food

Some brave people take their mass gainer shake as a dessert, right after a big meal. But one of the worst times to take mass gainer is right after food.


Well, your stomach will already be occupied with plenty of calories from your meal, so throwing an extra 2000 calories into the mix is going to put even more stress on your digestive system.

So by taking your mass gainer at least 3 hours away from meal time, you’re much less likely to feel sick.

Take Half A Serving Twice A Day

The goal of taking mass gainer is to help you gain weight.


Now, when it comes to gaining weight, the only thing that matters is being in a calorie surplus. In simple terms, this means you consume more calories over the course of a day than you burn.

So whether you take your mass gainer as 1 big serving or 2 small servings, it doesn’t really matter. At the end of the day, you’re consuming the same amount of calories.

By splitting your mass gainer into 2 small servings, you’re going to be consuming 2 lots of 1000 calories compared to 1 lot of 2000 calories, which is much easier on your digestive system. As a result, you should feel less nauseous.


In summary, mass gainer makes you feel sick as you consume a huge amount of calories in a very short space of time.

That’s all for this article, but can you take weight gain supplements without working out? Or, perhaps you’re wondering how many mass gainer shakes a day you should take?

Hope this helped!