Collagen Side Effects: What To Know About Taking Collagen Supplements

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.

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.

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).

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.

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.

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.*

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.* 

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