Author: David Sasha Schulz (Bachelor of Science, Human Biology)
Does protein make you poop? Protein powder will likely only cause notable digestive issues if someone is lactose intolerant or has IBS. This will likely only be an issue for those who can’t handle lactose in their diet, making plant-based proteins and whey isolates a great alternative.

Does Protein make you Poop?
While the vast majority of people have no problem digesting protein powder, some people will notice significant digestive issues when taking this common supplement. It’s not uncommon for people to experience gas, bloating, and diarrhea after consuming protein. For most people, however, this will not be a major issue.
With this being said, do protein shakes make you poop more than you would like? Keep reading to find out why this may be an issue.
Digestive issues with protein powder most commonly arise when someone is lactose intolerant and is still consuming dairy-based protein powders. Lactose intolerance is very common, with approximately 65-70% of the world’s population experiencing this condition. This condition is caused by the body not producing enough lactase, the enzyme that digests lactose. You can likely determine if you’re lactose intolerant based on how your body reacts when you consume dairy-based products. Any digestive issues, or diarrhea, are a likely sign that you’re lactose intolerant. If you’re unsure, check with your doctor to get tested.
Another reason protein powders may make you poop is that you have IBS (Irritable Bowel Syndrome). Whenever you eat, you initiate something called the gastrocolic reflex, where the gastrointestinal tract is stimulated by the food you’re eating. People with IBS appear to have a much stronger colonic response when the gastrocolic reflex is activated. This leads to them needing to defecate almost immediately after eating. It is also usually accompanied by other symptoms including gas and stomach pain. If you find that you’re pooping right after protein shakes, or any other food for that matter, this may be a sign you’re suffering from IBS. Again, if you believe you have IBS, please get in contact with your doctor to discuss potential treatments.
Overall, protein powders are most likely to cause stomach discomfort in people due to lactose intolerance or IBS. If you suffer from either of these conditions, then there are several things you can do to address the issue, and ideally have less digestive issues whenever you take protein. These solutions are covered more in-depth in the section below.

The real problem is diarrhea, so what can be done about it?
Now, whether you are lactose intolerant, have IBS, or just experience general discomfort when you eat protein powder, then you may be wondering what you can do to alleviate these digestive issues. One of the major issues people experience is diarrhea, so here are a few tips we have to alleviate this issue between your protein shakes and bowel movements. If protein powder makes you poop, keep reading to find out how to solve this problem.
1. Mix with Water instead of Milk
2. Replace protein source
Of course, your next course of action if you’re taking a whey concentrate or casein protein would be to replace the type of protein you’re consuming. First, you could try switching to a whey isolate as they have less lactose than whey and casein. However, if discomfort persists, then you can consider switching to a non-dairy protein instead.
Now, especially if you’re lactose intolerant, you may be wondering why we’re recommending a whey isolate. Isolates are a much more refined source of protein compared to concentrates. While concentrates typically have around a 80% protein concentration, isolates are typically closer to 90%. This means much of the lactose from whey is removed, and these supplements are often suitable for lactose intolerant individuals.
Of course, an even better option if you’re especially sensitive to lactose would be to switch to a non-dairy protein. This could be a plant-based, egg-white, or beef protein powder. While you can be confident that there will be no lactose whatsoever in these supplements, keep in mind that they will usually have lower bioavailability, different texture, and potentially less protein per serving when compared to a whey isolate.

3. Switch protein brand
Now, even if you’ve already switched to a whey isolate or plant-based protein, you may still be experiencing some discomfort. Ultimately, it may come down to certain ingredients found in protein powders instead of the protein itself.
Ingredients like sugar alcohols, stevia, and monk fruit have all been shown to cause bloating, gas, and diarrhea in some people. Also, certain people are especially sensitive to food additives like thickeners and emulsifiers, which may cause unpleasant symptoms as well.
So, we recommend checking the ingredient list on whatever protein you’re currently using. If you see a long list of extra ingredients – namely sweeteners and additives – these may be the culprit behind your digestive issues. In this case, we recommend switching to a protein brand with as few ingredients as possible.
Best Protein - Transparent Labs Grass-Fed Whey Isolate
If you’re experiencing digestive issues from protein, one of the main issues may be that you’re using a concentrate instead of an isolate. Switching to a high-quality isolate may make a difference because it has a significantly lower lactose content. Let’s see why Transparent Labs Grass-Fed Whey Isolate is a great choice for those experiencing stomach discomfort, as well as just being a great protein overall.
With this product containing 28g of protein in each 120 calorie serving, it has a concentration of 93% protein by calories. With whey isolates having significantly less lactose than an average concentrate, this would be a great option for lactose intolerant people who still want to use a whey supplement.

Photo by @transparentlabs
This is also made with 100% grass-fed dairy, which is largely considered healthier than inorganic dairy. While this protein is made with all-natural ingredients containing no major additives, the inclusion of stevia may cause some stomach discomfort for some. If you know you’re sensitive to stevia, this may not be the best option for you.
Also, it’s worth noting that this is a fairly expensive protein supplement, especially when compared to concentrates. Each serving of Transparent Labs’ whey isolate will cost you around $1.81. While this is somewhat pricey, you’ll be hard-pressed to find a higher-quality protein supplement anywhere else.
FAQ
Does protein make you poop or constipated?
Can protein give you diarrhea?
What happens if you eat too much protein at once?
Does Protein help you Poop?
Conclusion
Overall, while protein may cause mild digestive issues for some people, those with IBS, and those who are lactose intolerant will most likely need to avoid dairy-based protein shakes. To avoid some of the digestive issues related to protein powder, we recommend drinking it with water, switching protein sources, or switching protein brands. Of course, consult with your doctor if these issues persist.
For a great whey isolate supplement that we believe will be good for most people with digestive issues, we recommend Transparent Labs Grass-Fed Whey Isolate.
Do you experience any digestive issues when you drink protein? Have any solutions not covered in this article? Let us know in the comments below!
References:
- Lauren Matheu, "Do I need to use protein powders?" Colostate, https://www.chhs.colostate.edu/krnc/monthly-blog/do-i-need-to-use-protein-powders/, JUNE 2022
- Theodore M Bayless, "Lactase Non-persistence and Lactose Intolerance" NCBI, https://pubmed.ncbi.nlm.nih.gov/28421381/, 2017 May
- Jordan C. Malone, "Physiology, Gastrocolic Reflex" NCBI, https://www.ncbi.nlm.nih.gov/books/NBK549888/, MAY 1, 2023
- "The Rundown on Protein Powders" GSU, https://recreation.gsu.edu/2023/03/31/the-rundown-on-protein-powders/, MARCH 31, 2023
- Mayo Clinic Staff, "Nutrition and healthy eating" Mayoclinic, https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/artificial-sweeteners/art-20046936
- "Food additives" Betterhealth
- "Grass-fed cows produce healthier milk" UMN, https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/food-additives
Why Trust Us?
During his formal education, Sasha has taken dozens of courses in biochemistry, nutrition, statistics and research methods which allows him to have a deep understanding of nutritional science. Since graduating he continues reading scientific literature to stay current on the latest evidence in all areas relating to his profession.
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