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Collagen Side Effects: What To Know About Taking Collagen Supplements

Alexandra Engler
Author: Expert reviewer:
Updated on March 10, 2022
Alexandra Engler
mbg Beauty Director
By Alexandra Engler
mbg Beauty Director
Alexandra Engler is the beauty director at mindbodygreen and host of the beauty podcast Clean Beauty School. Previously, she's held beauty roles at Harper's Bazaar, Marie Claire, SELF, and Cosmopolitan; her byline has appeared in Esquire, Sports Illustrated, and
Ashley Jordan Ferira, Ph.D., RDN
Expert review by
Ashley Jordan Ferira, Ph.D., RDN
mbg Vice President of Scientific Affairs
Ashley Jordan Ferira, Ph.D., RDN is Vice President of Scientific Affairs at mindbodygreen. She received her bachelor's degree in Biological Basis of Behavior from the University of Pennsylvania and Ph.D. in Foods and Nutrition from the University of Georgia.

Anytime you start a new supplement, product, or routine—it's natural to want to know the side effects. You want to know what you're getting yourself into, no?

Well, some ingredients come with notable cautions, while others seem to be pretty tolerable or wholly benign.

Where does collagen fall on that spectrum? Let's dive in. 

What are collagen supplements?

Collagen is a family of proteins found widely in all mammals, with types I, II, and III being the most common in the human body.

As far as its role in the body, it helps make up the structure of our skin, bone, cartilage, muscle, and more, with the purpose of helping tissues be elastic and withstand stretching (so, for example, it keeps skin looking young and supple).*

We actually make our own internal supply of collagen, via our cells' fibroblasts (assuming they have the amino acids and other required nutritional building blocks they need).

In fact, it's made by our body throughout our lifetime; however, it also decreases with age, and your natural endogenous levels can also be reduced by environmental factors and stressors, such as sun damage and high-sugar diets1

This is where collagen supplements come in: Collagen supplements are broken-down digestible forms of collagen (derived from things like cows, fish, and chickens), usually in a powdered form.*

When ingested, your cells' fibroblasts can use the amino acids to stimulate and enhance your own natural collagen production.* (If you are interested in trying a supplement, we rounded up our all-time favorites—check it out for our recommendations.) 

All sounds great, yes? Well, you might be wondering if there is anything negative you need to keep an eye out for when trying a new supplement.

Here, we explain the most common complaints. 


Collagen is a family of proteins found in the human body. Collagen supplements are broken-down digestible forms of collagen and when taken, your cells' fibroblasts can use the amino acids to stimulate and enhance your own natural collagen production.*

Short term side effects & cautions. 

Overall, collagen peptides are safe for consumption, and few side effects, complaints, or cautions are reported. They fall into the "benign" bucket.

However, everyone is different, and everyone's body reacts to products in unique ways. This is why some side effects are reported anecdotally. 

Whether the experiences are directly tied to the collagen peptides is difficult to pinpoint, particularly considering collagen powders can contain other active ingredients and some "Other ingredients" too (depending on the brand and product).

So it's important to note that individual issues with collagen powders may be triggered by another player in the specific brand's formula, not the peptides themselves: 

  • Bad taste in mouth. Some people report unpleasant taste with their collagen powders. The most common tastes reported are from the collagen itself (which some people describe as strong) or from the flavoring (which can be either too saccharine or comes with a tangy or bitter aftertaste). If this is a concern, we recommend mixing it with a smoothie or coffee, as they can help mask the flavor. We also recommend checking whether high-quality sweeteners are used (e.g., organic monk fruit extract, organic coconut sugar) instead of the artificial stuff. If you don't personally like unflavored collagen blends, look for a flavored option (again, with high-quality plant-based flavors like organic cocoa, for example).
  • Stomach upset. Anecdotally, some individuals report bloating, stomach upset, and fullness. This isn't common, and we suspect this might have more to do with the specific formula and additives on a brand-by-brand basis than collagen peptides in general. 
  • Allergens. Always be sure to check out the full ingredient list, and where the collagen is sourced from (bovine, marine/fish, or chicken)—and keep an eye out for any ingredient that you may personally have sensitivities to. 
  • Vegan status. No collagen is vegan because collagen peptides are derived from animals (cows, fish, and chicken most often). This can be a pain point for strict vegans, while other plant-heavy consumers and even vegetarians consider this pure protein source acceptable even though it's animal-derived.

If you have any concerns or questions about the specific powder you are trying, speak to your health care practitioner and reach out to the brand directly for more information.  


Only a few side effects of collagen have been reported. However, everyone's body is different and will react to it in unique ways. Possible side effects include a bad taste in the mouth, bloating, or allergens.

Positive long-term "side effects."

This all being said, if you stick with it—you may experience some pretty impressive long-term results.

"Hydrolyzed collagen is predigested, so it does not go through that first-pass digestion in the GI tract," says board-certified dermatologist Joshua Zeichner, M.D. "The collagen fragments can be absorbed as is and circulate throughout the body to exert their effects."* 

And if you think the benefits are just hype, we assure you—there's enough data to support what we're saying here.

"There are, in fact, numerous published studies on collagen peptides, and the science continues to build. When there are enough clinicals to compile them in a systematic review or meta-analysis, that's definitely a sign that a certain bioactive or nutritional component has a noteworthy breadth of clinical evidence,"* says Ashley Jordan Ferira, Ph.D., RDN, vice president of scientific affairs at mindbodygreen.

Here, all the positive things collagen supplements can do for your body:


Beauty benefits. 

The research 2shows that these collagen peptides are able to support skin elasticity, hydration, texture, and dermal collagen density2.* How? Well hydrolyzed collagen peptides have been shown to help promote your body's natural production of collagen3 and other molecules that make up the skin, like elastin and fibrillin.*

Additionally, this double-blind, randomized, placebo-controlled clinical trial found that participants' moisture levels in the skin were seven times higher4 than those who did not take collagen supplements.*

And another double-blind, randomized, placebo-controlled clinical trial found that when a small group of women took a collagen supplement that was also formulated with hyaluronic acid and a few other bioactives, they experienced a significantly smoother appearance of wrinkles.* 

That's not all, it can also help hair and nails.*

Keratin—or what hair is made up of—is made up of amino acids, many of which are found in collagen supplements such as proline, cysteine, and lysine.

For nails, one study found that when patients took collagen daily for 24 weeks, it helped support their nail health5, including better growth rates, reduced breakage, and improved appearance.* 


Promotes gut health.

One of the reasons collagen supplements have become so widespread is the potential gut health benefits.*

While this is a newer area of study for collagen supplements, research has found that levels of certain types of collagen are lower in individuals with digestive challenges6.*

Additionally, research has found that one of the main amino acids in collagen, L-glutamate, supports the intestine by neutralizing oxidative stress7 and acts as a major fuel source8 for the cells in the intestine.*

The cells of our gut lining also use proline and glycine for energy, and these are two additional amino acids found in collagen.*


Joint, muscle & bone health. 

Collagen has very important roles in the joints, muscles, and bones. Researchers show that supplementation can help support all three of these areas.*

For joints, one randomized clinical trial found that people who took a type II collagen supplement for 180 days experienced improvements in their physical function and helped improve joint mobility and comfort.* 

For bone health, it's a more time-intensive benefit to track—simply given how long the bone turnover timeline is—however, this clinical trial found that postmenopausal women had enhanced bone density9 at 12 months after consuming collagen peptides daily for a year.* 

And for muscles, collagen supplementation can help along with a workout routine. In one small clinical study, men who took collagen daily while participating in an exercise program gained more muscle mass10 than those who only completed the exercise program.*


There are a variety of potential long-term benefits of taking collagen supplements, including improvements in skin elasticity, hydration, and texture, improved gut health, and better joint, muscle, and bone health.*

The takeaway. 

It's normal to be cautious about starting a new supplement routine.

However, collagen tends to be pretty safe and tolerable, as long as you find a clean, smart formula that works for you. 

Alexandra Engler author page.
Alexandra Engler
mbg Beauty Director

Alexandra Engler is the beauty director at mindbodygreen and host of the beauty podcast Clean Beauty School. Previously, she's held beauty roles at Harper's Bazaar, Marie Claire, SELF, and Cosmopolitan; her byline has appeared in Esquire, Sports Illustrated, and In her current role, she covers all the latest trends in the clean and natural beauty space, as well as lifestyle topics, such as travel. She received her journalism degree from Marquette University, graduating first in the department. She lives in Brooklyn, New York.