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Evidence Based

This article is based on scientific evidence, written by experts and fact checked by experts.

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This article contains scientific references. The numbers in the parentheses (1, 2, 3) are clickable links to peer-reviewed scientific papers.

Collagen and Bowel Movements: Can This Supplement Improve Gut Health?

Written by Dr. Michael Ruscio, DC on June 23, 2022

Written by Dr. Michael Ruscio, DC on June 23, 2022 — Reviewed by Heidi Turner

Exploring the Link Between Collagen and Bowel Movements, Leaky Gut, and Dysbiosis

• General Benefits of Collagen|
• How Can Collagen Help With Gut Health?|
• Collagen and Bowel Movements|
• What Forms of Collagen Are Best?|
• Reasons You Should Add Collagen|
• Collagen Side Effects|
• Collagen Is a Multi-Purpose Health Tool|

You’ve probably already heard of collagen as a beauty and skincare supplement, but did you know it may support your gut health too? 

Research is still in progress, but cell and animal studies are showing promising benefits of collagen for healing leaky gut, reducing inflammation, and even increasing short-chain fatty acid (butyrate) production [1, 2]. Animal studies have shown that collagen may also improve dysbiosis in the gut microbiome [3, 4, 5].

In this article, we’ll discuss the many benefits of collagen, how collagen can support gut health, collagen and bowel movements, the difference between marine vs. bovine collagen, how to add a collagen supplement to your diet, and any side effects or downsides of collagen supplements. 

General Benefits of Collagen

Collagen has well-studied benefits for skin, nail, joint, and muscle health. It’s the most abundant protein source in the body and the main ingredient in our connective tissues, such as ligaments and tendons. 

You can think of collagen as structural support for the body — it’s very rigid and resistant to stretching, which is why it’s excellent for bones, teeth, and cartilage. However, collagen isn’t considered a complete protein source due to the absence of the amino acid tryptophan [6].

Tryptophan is an important amino acid for sleep regulation and quality, as well as a precursor for serotonin, so we do need to get it from our diet. However, tryptophan can be readily found in other protein sources such as chicken, turkey, and beef [7].

There are 28 different types of collagen, but we mainly need types I, II, and III, which are used in most supplements. Type I collagen accounts for 90% of the total collagen in the human body [8, 9].

Besides collagen supplements, you’ll find it in muscle meats (chicken, beef, pork, etc.) and fish, as well as bone broth and gelatin. 

The most common health benefits of collagen that have been studied so far include:

• Skin health: Improvements in hydration, skin elasticity, wrinkles, and cellulite [10, 11, 12, 13, 14]
• Nail health: Increased growth and less breakage [15]
• Joint health: Improved osteoarthritis [16, 17, 18], rheumatoid arthritis (specifically with type II collagen at a low dose) [19, 20], improved activity-related knee pain [21]
• Musculoskeletal health: Increased bone density [22, 23], bone metabolism [24], tendon injury rehab [25], natural collagen synthesis [26], muscle protein synthesis [27]
• Exercise performance and recovery: Increased ability to quickly generate muscle force during exercise [28], improved short-term muscle soreness and recovery after exercise [29], reduced the short-term decline in performance and increased recovery time [30]

In our clinic at the Ruscio Institute for Functional Medicine, we’ve also seen increased energy and decreased fatigue in patients who supplement with collagen powder in their diet, especially if they weren’t getting enough protein before.

How Can Collagen Help With Gut Health?

Research is ongoing, but there are some exciting cell and animal studies looking at the benefits of collagen for gut health. 

Two studies involving cell models that were designed to mimic the human gut found reduced leaky gut [1], reduced inflammation [1], and increased short-chain fatty acid (SCFAs) production [2]. The SCFA butyrate has been shown to have anti-inflammatory properties and is an important energy source for colonic cells in the digestive tract.

One 2022 animal/human cell study explored the effects of fish collagen in a mouse model of inflammatory bowel disease (IBD) and in human immune cells collected from IBD patients. The results showed that mice given collagen had reduced gut inflammation and improved balance of the gut microbiota compared to mice that weren’t given collagen. 

Additionally, human immune cells that were collected from IBD patients and treated with collagen showed changes that demonstrated an anti-inflammatory and antioxidant effect [4].

If we think about the building blocks of collagen as a type of protein, we can break it down into essential amino acids. Several of these amino acids, like glycine and glutamine, are also recommended for healing the gut lining and supporting gut health. So some of these nutritional building blocks in collagen are fundamentally supportive to a healthy gut.

This study is far from definitive, but it shows the potential of collagen to reduce inflammation in the digestive system, support patients with leaky gut syndrome, and improve dysbiosis.

Collagen and Bowel Movements 

There are no specific studies showing improvements in constipation or diarrhea with collagen supplementation. However, depending on the root cause of the motility change, we can infer that the effect of collagen on bowel movements may be positive due to its studied effects on issues like dysbiosis and leaky gut. 

If dysbiosis in the large intestine is behind chronic constipation, for example, collagen may have some benefit by improving the gut microflora and increasing butyrate production, resulting in better regularity. 

Collagen may also be helpful for these symptoms and other digestive imbalances from a nutritional perspective of getting enough protein. At the Ruscio Institute, we’ve seen great results from getting patients to a more optimal daily protein intake. 

What Forms of Collagen Are the Best? 

Collagen powder can be sourced from many different animal sources (and one plant-based), including [10, 11, 31]:

• Pig (porcine)
• Fish (marine)
• Cow (bovine)
• Chicken
• Squid
• Algae

The most popular supplements are bovine and marine collagen. We typically recommend marine collagen for a few reasons. One is that there’s some evidence suggesting it’s more easily absorbed, has fewer contaminants, and is less likely to cause inflammatory reactions [32].

Marine collagen may also be preferable for some people due to religious or dietary restrictions around meat. 

As far as protein and nutrient content, many of us could use more fish in our diet, and eating more fish may actually get us closer to a true Paleo style of eating [33]. 

Hydrolyzed Collagen vs. Gelatin

Most collagen supplements are either hydrolyzed collagen or gelatin. While gelatin has its own benefits, hydrolyzed collagen may be better absorbed due to its low molecular weight. It’s also the most commonly used form in research [34, 35]. Hydrolyzed means the collagen has been broken down using enzymes or acids, making it easier to digest. 

Collagen in Food vs. Supplements

It’s likely easier to obtain higher amounts of collagen from supplements than from food sources [6], and this may be necessary for those who want to achieve the therapeutic effects seen in scientific research. Several of the studies used doses of collagen at 15 grams per day or higher, and this may be difficult to obtain from diet alone [6].

For those wanting to increase collagen intake from their diet, foods such as bone broth or meats that contain lots of connective tissue (pot roast, brisket, chuck steak) are possible options [36]. However, one study found that collagen supplements were superior to bone broth for increasing levels of amino acids (proline, hydroxyproline, lysine) needed for collagen synthesis [37].

Zinc and vitamin C are also needed to produce collagen in the body, so consuming foods that are higher in these nutrients may help increase collagen production [36].

Reasons You Should Add a Collagen Peptides Supplement to Your Diet

Let’s review some reasons you might want to add collagen to your diet. Adding collagen may help:

• Increase protein intake for those who aren’t getting enough through their regular diet
• Improve body composition (increasing muscle mass and decreasing excess fat)
• Support nail and skin health
• Support joints, muscle, and connective tissue 
• Improve energy/fatigue
• Improve gut health, including sealing up leaky gut and balancing the microbiome

Ways to Add Collagen to Your Meals and Snacks

Collagen protein is flavorless and easily added to coffee or tea, or other hot beverages. This makes it quite convenient for most people to add collagen to their morning cup. 

You can also add collagen to smoothies, soups, in baked goods like muffins or quick breads, oatmeal, chia pudding, protein shakes, and more. Adding collagen to these items makes for a more nutritionally balanced meal or snack (protein + carb), helping to keep blood sugar balanced. 

Are There Any Side Effects or Downsides of Collagen?

By and large, collagen supplements appear to be safe and do not result in increased side effects compared to placebo in most studies. 

One study noted that some gastrointestinal symptoms (nausea, dyspepsia, diarrhea, and gas) occurred in those who took collagen, but there was no increase in side effects compared to placebo and it was unclear what caused the side effects [18].

There’s a small chance that collagen could provoke an allergic reaction in those who are allergic to the source of collagen (bovine, porcine, marine). For example, someone with a shellfish allergy may have an allergic reaction to marine collagen [38].

To avoid any potential side effects and to determine whether supplementing with collagen would benefit you, consult with your healthcare provider. 

Use Collagen as a Multi-Purpose Health Tool

Collagen protein has many potential benefits for your gut health, energy levels, and connective tissue health. It’s not a magical cure by any means, but it can help support multiple areas of your health. For some people, there may be a beneficial connection between using collagen and bowel movements, either increasing or decreasing motility depending on your needs.

Look for a collagen supplement that has been tested for heavy metals and is free from common allergens, additives, and fillers. 

If you want more guidance on using your diet to promote a healthy gut, you can check out my book, Healthy Gut, Healthy You. 

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience, including marine collagen. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.