Should You Take Collagen for Gut Health The Benefits, Side Effects & Contraindications, According to a Functional Dietitian - by Jenna Volpe, RDN, LD, CLT

Should You Take Collagen for Gut Health?

“Should I be taking collagen for gut health?” Believe it or not, I’ve been hearing that question from clients at least once every week in my functional nutrition clinic lately!

And if you’ve made it here to my little corner of the internet, chances are you’re probably wondering the same thing. (If so, look no further!  Keep reading.)

Less than a decade ago, the majority of people hadn’t even heard of collagen – let alone add it to their morning coffee and smoothie drinks.  But as chronic digestive health issues (like IBS and leaky gut) have begun to soar, many are now leaning more into “food as medicine” and exploring functional foods (such as bone broth and collagen peptides) in efforts to heal their gut.

So, is this new collagen trend just a passing craze, or are all those people you’ve seen dumping collagen powder into their morning beverages actually onto something?

As a functional dietitian and holistic nutritionist who specializes in gut health, I feel like it’s my duty to address that burning question once and for all!  But first, please keep in mind:

  • This article is intended to be informative and educational. This is not medical nutrition advice!  Make sure to consult a qualified doctor and functional nutrition professional for individualized care if you’re navigating digestive issues of any kind.
  • One size never fits all!  What has worked for others still may not work for you, since everybody is unique.
  • No single food or supplement of any kind as a stand-alone intervention should ever replace a balanced diet or be treated as a “be-all-end-all” solution or quick-fix to any health issue.

Affiliate disclosure: This article contains some affiliate links* for products that meet my high standards as a holistic registered dietitian. I only recommend and endorse products that I love and use personally. As an Amazon Associate, if you make a purchase using any of my affiliate links, I will make a small commission at no extra cost to you. 🙂

Okay, now let’s dive in!

First things first: what is collagen?

Collagen is a type of protein made up of amino acids (building blocks of protein).  

From a physiological standpoint, collagen is the most abundant protein in the body (1) – not just in humans, but in many types of animals too.  Collagen is a primary matrix for skin, bones, tendons and ligaments. 

In the health and wellness industry (and for the context of this article), collagen has evolved into a type of “functional food” – aka a food or nutraceutical supplement which offers health benefits beyond general nutrition (2) because of the benefits it has to offer!

Collagen in the body

While there are said to be 28 different types of collagen existing in nature, most of the collagen types found in the body and in our supplement industry are type I, II, III or IV, with type I making up close to 90% of collagen in the human body in that it forms the basis of connective tissue. (1)

Collagen in supplements

In the supplement industry, you’ve likely seen various types of collagen powders and pills, some for topical use and other brands meant for internal use.  But it’s important to keep in mind, not all collagen supplements are created equal!

For example, some collagen is sourced from animals such as bovine (cows), porcine (pigs) or poultry (chickens/turkey), while other collagen supplements are marine-based or vegan.

From a molecular standpoint, some collagen supplements may come in the form of peptides (type I derived) aka “hydrolyzed” (3), while type II collagen is often referred to as “cartilage collagen.” (4)

The collagen most often taken for gut health purposes is collagen peptides (or hydrolyzed collagen).

What is the gut?

When you hear someone refer to the “gut,” they’re not just talking about your stomach!  Your gut encompasses your entire digestive tract or “gastrointestinal tract” which begins in your mouth, and also includes the throat, esophagus, stomach, intestines, colon, rectum and anus.

Research from a 2014 study in the Scandinavian journal of gastroenterology established that the surface area of an adult’s gut is actually big enough to cover about half of a badminton court!  (5)

The gut is not considered to be inside the body, but rather a mucosal barrier (much like the skin) which serves as a boundary in charge of what can enter our bloodstream (inside the body) versus what must stay out.  The gut is sort of like the inside of a donut hole, if that makes sense!

The gut (alongside the liver, kidneys and skin) also serves as a primary detoxification organ responsible for digesting and absorbing nutrients from food while eliminating waste.

Why care about gut health?

Aside from serving as a powerful selective gatekeeper, taking what we need and leaving the rest (when it comes to foods and chemicals), your gut is also majorly synced up with pretty much every other aspect of health in one way or another.  

(You may or may not be familiar with ancient philosopher and doctor Hippocrates’s famous quote, “All disease begins in the gut!”)

Your gut and your immune system

It’s been well-established by researchers nowadays that about 70% of the immune system is synced with the gut. This branch of the immune system is often referred to as “Gut-Associated Lymphoid Tissue” (or GALT for short). (6, 7)

That said, it’s no surprise that so many people with autoimmune disorders and allergies are also found to have an imbalanced microbiome (aka “dysbiosis”) and a subsequently compromised gut barrier (aka “leaky gut syndrome” or “intestinal hyperpermeability”).  (6, 8)

To say that a healthy gut is fundamental to maintaining a healthy, balanced, resilient immune system is an understatement!

The gut-brain axis

You may or may not have heard the gut referred to as the “second brain” – and that’s for good reason!  Much like the immune system, research has also uncovered that your gut is intimately connected with your central nervous system.  In fact, the gut has its own special network of nerves, referred to as the “enteric nervous system!” (9)

All of that said, it should come as no surprise that a healthy gut is one of the secret keys to feeling calmer and happier (aka less anxious and less depressed) more often!

On the flipside, an unhealthy gut is unfortunately a big gateway into developing mood disorders like depression, anxiety, and much more. (12, 13)

The gut-skin axis: as within, so without

“As within, so without…”  – Paracelsus 

This is a famous saying according to Paraelsus, an ancient medical philosopher and alchemist.  While there are lots of different directions an interpretation could go, one way this rings true is in the realm of the gut (within) and the skin (without).  

Of course, in some ways, the gut and the skin are two completely different organs – but in certain other ways, two are actually pretty parallel!  Your gut is to your skin as “yin” is to “yang.” In other words, the gut is the inner version of the “outer” (skin).  They both serve as a barrier between the inside of our body and the outside world!  

Your gut and your skin are also the two primary “homes” of the human microbiome (ecosystem of microbes which live in and on us, impacting virtually every aspect of health).

The intimate gut-skin connection may explain why both the gut and the skin benefit from collagen supplementation. 

Enter… the multitude of potential collagen health benefits!

General health benefits of collagen, according to science

From a general health and wellness standpoint, there are quite a few great reasons so many people are adding collagen supplements into their routine! 

Supplementing with collagen (mostly type I for skin, muscles and gut, or type II for joints) has been shown in research studies to provide the following benefits:

  • Improved skin elasticity & skin regeneration (14, 15, 16, 17)
  • Faster wound healing (such as in cases of ulcers and burns) (14)
  • Healthier joints and reduced joint pain in cases of osteoarthritis & rheumatoid arthritis (14, 17, 18, 19)
  • Improved muscle strength/muscle mass in cases of sarcopenia (muscle wasting in the elderly) (14)
  • May improve bone density (20)
  • May support a healthier gut (see below)

Gut health benefits of collagen, according to science

Below are a plethora of evidence-based reasons you just might benefit from taking collagen to improve your gut health!

May support healthier intestinal permeability

As you can see from the nutrition fact label of this collagen peptides canister, collagen is naturally abundant in gut health-promoting amino acids L-glutamine, proline and glycine which are correlated with healthier intestinal permeability according to clinical studies.  (21, 22, 23)

(Anecdotally, collagen peptides have also been a wonderful ally on my own gut-healing journey.)

Improved esophageal function in GERD cases

A study which injected participants with gastroesophageal reflux disease (GERD) with cross-linked bovine dermal collagen found that all participants experienced a significant reduction in their heartburn symptoms. (14)

Note:  A limitation of this study is that the collagen was not taken internally; it was injected!

Healthier gut microbes + better immune function

In a 2021 Food chemistry study which investigated changes in the gut microbiomes of immunosuppressed mice before and after receiving a fermented collagen peptide + jackfruit concoction, the following biomarkers improved (15):

  • Antioxidant capacity
  • Lactic acid (produced by beneficial bacteria strains Lactobacillus)
  • Overall gut microbiota composition
  • Reduced damage to colon tissue
  • Spleen and thymus function
  • Reduced pathogenic (unhealthy) microbe count

May reduce bloating and mild digestive distress

I’m excited to share that some researchers finally took it upon themselves to find out whether or not taking collagen for gut health is actually worth the hype (and money), in a very recent two-phase “mixed methods” study via JMIR Formative Research from May 2022. 

To their pleasant surprise, they uncovered that about 20 grams a day of type I collagen peptides (the most common dose of collagen prescribed by most registered dietitians) for just six weeks led to a reported 93% improvement in mild digestive symptoms (24) including:

  • Bloating
  • Stomach cramps
  • Abdominal pain
  • Diarrhea
  • Constipation
  • Flatulence
  • Irregular bowel movements
  • Acid reflux 

This study is exciting and promising because it’s in vivo (tested among real life human participants with digestive ailments) and because no other variables were included (i.e. fermented jackfruit).

Needless to say, while I’m glad there are finally more clinical studies coming out on collagen for gut health, we still need more research!  Especially since this study was only done on a very small group cohort (40 participants), the reports are somewhat subjective (based on evaluation of symptoms), and this study only included a demographic of “otherwise healthy” adult females with IBS. 

What’s the best type of collagen for gut health?

While research is suggesting that collagen capsules (of type II cartilage collagen) are most effective and user-friendly for people taking collagen for joint health, I’ve found both anecdotally and from research that taking type I collagen (peptides or hydrolysate) in powder form seems to be best for people looking to support a healthy intestinal barrier.

Are all collagen peptides created equal?

Just like all hamburgers are not the same, all collagen peptides are most definitely not created equal!

Below are some of my favorite brands of collagen peptides (in no particular order). They’re all 100% grass-fed, non-GMO, free of glyphosate (a broad-spectrum herbicide found to interfere with nutrient absorption) and third-party tested.

Designs for Health Whole Body Collagen Powder*

Orthomolecular CollaGEN*

Orthomolecular CollaGEN supplement - 8 oz cannister

Primal Kitchen Collagen Fuel*

Garden of Life Hydrolyzed Collagen Peptides*

(Side note: I understand this stuff gets expensive! That said, if you’d like to get a lifetime discount of 15% off these products and lots of other high quality supplements, I invite you to join my online dispensary where you can get discounted practitioner-approved supplements shipped to your door in just 3-6 business days, on demand. Click on the FullScript button below to get started.)Order supplements through my Fullscript store.

How to take collagen peptides

If you’re taking plain, unflavored collagen peptides, they’re pretty versatile and relatively tasteless when properly blended or incorporated into your favorite beverage or recipe!

Here are a few of my favorite ways to take collagen peptides:

  • Stir a scoop of plain or vanilla peptides to your morning coffee or tea
  • Dissove a scoop of collagen peptides into oatmeal or overnight oats
  • Blend it into your favorite smoothie recipe for extra protein

How much collagen?

In the study from May 2022, about 20 grams per day of collagen peptides for 6 weeks was deemed a clinically effective dose. (24)

According to a Nutrients study from 2019, if collagen is well tolerated from a gut health standpoint, and you meet criteria as someone who can benefit from collagen peptides supplementation, the most effective amounts of functional collagen peptides are about 2.5 to 15 g per day. (25)

(In real life, the above recommendations translate to a range of about 1 teaspoon up to 2 scoops of collagen peptides powder per day, depending on the amount of grams of collagen protein per scoop serving size.)

When in doubt, read the label to verify the serving size and number of grams of collagen per serving. And of course, consult with your functional nutrition practitioner as needed! 😉

The dark side of collagen: side-effects and contraindications

As a quick reminder, there’s no “magic bullet” when it comes to food and health – and collagen is not for everyone!  I’ve found in my clinic that not everyone with digestive issues will benefit from collagen. In fact, sometimes it can do more harm than good. 

Below are some possible risks, cons, and contraindications of supplementing with collagen.

Glutamine intolerance

Some people with a very compromised gut lining (such as in cases of inflammatory bowel disease) may not be able to process and absorb the high levels of glutamine (glutamate) in collagen.

While formal research on this is lacking, I’ve observed that a significant percentage of people with IBS-D or IBD who self-prescribe collagen for gut health will end up experiencing adverse reactions such as abdominal cramping and diarrhea.

Ammonia overload

Since collagen is exceptionally high in the amino acid glutamine, too much collagen can mean too much glutamine, which can potentially trigger certain gut microbes to produce ammonia – a known neurotoxin. (26)  

This explains why l-glutamine is considered to be “a toxic substance” when taken in relatively high doses, according to researchers from Annals of hepatology! (27)

Bottom line: too much of a good thing is often harmful. More is usually not better, and moderation is key!

Adverse food reactions

While some people have issues processing the glutamine/glutamates in collagen, others may have an adverse reaction to the constituents from the food source a particular collagen supplement is derived from. 

For example, if you have an allergy or sensitivity to beef, pork, chicken, shellfish, etc., you may have an adverse food sensitivity reaction from taking a collagen derived from the food source you’re allergic or sensitive to.

  • If you’re prone to adverse food reactions, the best way to find out if you have an allergy is to receive an IgE skin test panel via an allergist.
  • If you’re getting diarrhea, migraines, joint pain, skin rashes or fibromyalgia, and you suspect collagen is a possible culprit, the best way to know for sure whether or not you’re sensitive (versus allergic) to a specific type of collagen based on what it’s derived from is to run the Mediator Release (MRT) food sensitivity test alongside a certified LEAP therapist.

Collagen, tryptophan, and depression

Collagen is lacking an essential amino acid, tryptophan, which is needed in order to make serotonin (the primary neurotransmitter involved in mood regulation, which tends to be lower or depleted among people with depression).

The good news is that according to Nutrients, as long as you’re keeping your collagen within the allotted 2.5 to 15 grams per day (while maintaining a relatively balanced diet), collagen peptides can be taken safely without depleting tryptophan levels. (25)

Can collagen cause kidney stones?

Unfortunately, there seems to be a link between collagen peptides and calcium oxalate based kidney stones. (28)  

  • If you have a history of kidney stones, you should avoid collagen peptides and consult a kidney stone dietitian before trying collagen for gut health, just to be on the safe side!

Protein and kidney disease

Collagen is a potent source of dietary protein. People with chronic kidney disease (which can sometimes go hand-in-hand with gut health issues) are often advised to adhere to a dietary protein restriction, and should take this into account before adding collagen into their regimen. 

  • Either way, make sure to consult with a renal dietitian so you can get the best custom guidance for managing your kidney disease!

So, is collagen good for gut health? (The final verdict)

Okay, so I realize this article was a bit of a loaded answer to your question! But I hope it helped to provide you with some clarity and a more holistic understanding of how collagen can impact your gut health (and overall well-being), for better and worse.

All in all, I would say that for most people who are otherwise healthy but dealing with just minor gut-related woes (i.e. bloating, stomach discomfort, mild constipation, heartburn, acne, and/or eczema), a daily scoop collagen likely won’t hurt, and could become a wonderful functional food ally on your gut-healing journey.

A few things to keep in mind:

  • Not all collagen supplements are created equal! When it comes to supporting your gut health, opt for type I (collagen peptides) and make sure you’re choosing a product that is non-GMO, glyphosphate-free, 100% grass-fed (if animal-derived) and third-party tested.
  • More is not always better! Even in cases of “superfoods” and functional foods, too much of a good thing becomes harmful.

But if you’re dealing with any of the following:

  • Diarrhea-predominant IBS (“IBS-D”)
  • Inflammatory bowel disease (IBD)
  • Kidney disease
  • Kidney stones
  • Major depressive disorder
  • Adverse food reactions 

…you should err on the side of caution, and hold off on trying collagen until further notice!

Either way, please make sure to first consult your treatment team (specifically your doctor and dietitian) before trying collagen or dabbling in any new supplement that impacts your health, if you’re navigating a medical condition of any kind. 😉

Additonal resources and next steps

If you’d like to learn more about how to improve your gut health via my holistic, evidence-based, mutli-dimensional approach, I invite you to check the following articles:

And/or, please feel free to check out and enroll in my Complete Gut Repair Roadmap online course!

Complete Gut Repair Roadmap with Jenna Volpe - Learn More