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

At some point in our fitness journey, many of us turn to mass gainers to support muscle growth and weight gain.

These products are marketed as convenient and efficient ways to increase calorie and nutrient intake.

However, it’s not uncommon for people to experience side effects, like nausea, after consuming mass gainers, leaving them wondering why these supposedly beneficial supplements have such adverse effects.

So, throughout this article, I’ll examine various factors that could contribute to feelings of sickness when taking mass gainers to help you make more informed decisions when selecting and consuming mass gainers.

Man looking nauseous while drinking a mass gainer shake

Why Mass Gainer Can Make You Feel Sick

Mass gainers can potentially make you feel sick due to several reasons:

High Caloric Load

Mass gainers are designed to be calorie-dense, providing a significant amount of energy in a single serving.

Consuming a large number of calories at once can overwhelm your digestive system, leading to feelings of discomfort, bloating, and even nausea.

High Carbohydrate Content

Mass gainers often contain a substantial amount of carbohydrates, which can be challenging for you to digest.

If your body has difficulty breaking down and absorbing carbohydrates efficiently, it can result in gastrointestinal distress, such as gas, bloating, and an upset stomach.

Lactose Intolerance

Many mass gainers contain dairy-based ingredients, such as whey protein, which can be problematic if you’re lactose intolerant.

Lactose intolerance occurs when the body lacks the enzyme lactase needed to digest lactose, the sugar found in dairy products.

Consuming a mass gainer containing lactose can lead to digestive issues like abdominal pain, bloating, diarrhea, or nausea in lactose-intolerant individuals.

Poor Digestive Enzyme Function

You may have insufficient production of specific digestive enzymes required to break down the proteins, carbohydrates, or fats present in mass gainers.

This can hinder the proper digestion and absorption of nutrients, causing digestive discomfort and an upset stomach.

Allergens and Sensitivities

Bulking supplements often contain various ingredients, including potential allergens like soy, gluten, or artificial additives.

If you have allergies or sensitivities to these substances, consuming a mass gainer that contains them can trigger adverse reactions, ranging from mild discomfort to more severe symptoms like nausea, vomiting, or diarrhea.

Artificial Sweeteners and Additives

Mass gainers may contain artificial sweeteners and additives to enhance flavor or prolong shelf life. These additives, such as certain sugar alcohols or artificial sweeteners like sucralose or aspartame, can cause digestive issues in some individuals, including stomach upset, bloating, or diarrhea.

How To Stop Feeling Sick From Mass Gainer

Here are some tips to reduce nausea from mass gainer.

Adjust serving size

Check the recommended serving size on the mass gainer package and ensure that you’re not consuming more than suggested.

Sometimes, consuming too much at once can overwhelm your digestive system and leave you feeling nauseated.

Gradual increase

If you’re new to muscle gainers or have a sensitive stomach, it might be helpful to start with a smaller serving and gradually increase it over time.

This allows your body to adjust to the higher calorie and nutrient intake more easily and prevent indigestion.

Modify timing

Experiment with the timing of your mass gainer consumption. Some people find it more comfortable to consume it with a meal, while others prefer it between meals or as a post-workout shake.

Find a timing that works best for you and doesn’t cause any digestive issues.

Mixing technique

Pay attention to how you mix the weight gainer. Make sure you follow the instructions provided on the package and mix it thoroughly to avoid any clumps. Incomplete mixing might lead to queasiness.


Stay well-hydrated when consuming a mass gainer. The extra protein and carbohydrates can increase your body’s water requirements. Proper hydration may help with digestion and alleviate some discomfort.

Quality and ingredients

Check the quality and ingredients of the mass gainer you’re using. Some products may contain artificial sweeteners, fillers, or low-quality ingredients that can cause gastrointestinal distress in some individuals.

Consider trying a different brand or formulation if you suspect this could be the issue.

Food intolerances or allergies

It’s possible that you might have an intolerance or allergy to one or more ingredients in the mass gainer.

Pay attention to any specific ingredients that seem to trigger your symptoms and consult a healthcare professional if you suspect an intolerance or allergy.

Conclusion: Can Mass Gainer Make You Sick?

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!


Why does mass gainer hurt my stomach?

Mass gainer can cause stomach discomfort due to its high caloric and macronutrient content, large serving size, or individual sensitivity to certain ingredients. It may also be related to inadequate digestion or improper consumption.

Are you supposed to chug mass gainer?

No, you should not chug mass gainer. It is generally recommended to follow the recommended serving size and consume it slowly to allow for proper digestion. Chugging large amounts of mass gainer quickly can potentially lead to digestive discomfort or upset stomach.

What to avoid when taking mass gainer?

When taking mass gainer, it is advisable to avoid excessive consumption beyond recommended serving sizes. Additionally, it’s best to avoid consuming mass gainer on an empty stomach, as it may lead to digestive discomfort. Individual intolerances or allergies to specific ingredients should also be considered and avoided.