Marine Collagen: 6 Health Benefits, Side Effects & More

Collagen is the most abundant protein in the human body. It's found in our tendons, ligaments, skin, muscles, bones, and blood vessels—and it plays a vital role in maintaining our overall structural integrity.

Unfortunately, our bodies produce about 1% less collagen1 with each passing year, and we're consuming far less of it from natural sources than we used to. This isn't a recipe for good health—and is why dozens of food and supplement companies are beginning to make products that help you fill the void.* One of those being marine collagen.*

Much of the marine collagen sold today is derived from fish like cod or snapper, specifically the skin and scales of these fish. The collagen protein is removed and then broken down into smaller units of protein (or collagen peptides) through a process called hydrolysis (why you'll also hear these referred to as hydrolyzed collagen). These smaller bits make it so marine collagen peptides easily dissolve in hot or cold liquids, which makes it an easy addition to your morning coffee, smoothie, or oatmeal. And yes, it's odorless and tasteless.

As with all sources of collagen, the body doesn't simply absorb marine collagen whole and deliver it directly where it needs to go.* It breaks the collagen down into its individual amino acids, which are then absorbed and utilized by the body.* While it contains 18 amino acids, marine collagen is characterized by high levels of glycine, proline, and hydroxyproline. It's important to note that marine collagen contains only eight out of the nine essential amino acids, so it's not considered a complete protein.

The main differences come down to collagen sources and diet preferences.

As for diet preferences, that's pretty self explanatory: If you don't eat meat, but you do eat fish, you'll likely opt for marine. But if you do eat animal-products, you'll likely opt for bovine. No matter what you choose, look for sustainable, clean sourcing.

As it naturally occurs, collagen acts as a kind of scaffolding that keeps our faces looking nice and plump. But collagen production naturally declines as we age, slowly robbing us of these perks. The good news is, supplementing with collagen may help support this process.*

Animal research has found that consuming marine collagen helps maintains dermal thickness on mice by promoting the number and activity of skin fibroblasts, or cells in the dermis that produce collagen and other fibers—and research on humans seems to confirm this effect.* In one study3, women who took a supplement containing hydrolyzed Type I collagen derived from tilapia had better supported skin with diminished appearance of lines, photo-aging, and better maintained moisture levels.*

The most abundant amino acid in marine collagen, glycine, has promising sleep-supporting perks.* One review of research revealed that ingestion of glycine before bed helped maintain satisfactory levels of self-perceived sleep quality.* It also suggested that glycine may help maintain core body temperature, which is associated with better sleep.* Erratic spikes and dips in blood sugar can also interfere with quality sleep, while marine collagen (which often contains around 10 grams of protein per serving) can help maintain normal levels.*

Everything from too much stress to a poor diet has the potential to damage the delicate tissues lining the intestines. This contributes to "leaky gut," a condition in which foreign particles are able to enter your bloodstream and wreak havoc on your body, increasing inflammation and your risk for autoimmune diseases. The good news: Not only is marine collagen easily digestible, but it may help support your gut, thanks to its amino acid profile.*

Two amino acids, glycine and glutamine, may be particularly helpful, as they both play a role in supporting the tissue that lines the digestive tract.* Glycine is particularly helpful at maintaining inflammation4, making it helpful for managing inflammatory gut conditions;* and glutamine is necessary for the health of the enterocytes, or epithelial cells, that line your gastrointestinal tract.*

Collagen is a concentrated source of the amino acid glycine, which helps your body produce creatine.* In turn, creatine has been shown to help support muscle mass5 and exercise performance6.* It's also a great source of proline, which acts as an antioxidant7 and helps monitor cellular damage that might cause post-workout achiness.*

While marine collagen doesn't contain the minerals you'd typically associate with bone health, one animal study8 suggests that it may help support the absorption of calcium, phosphorus, and other minerals into the body.*

The absorption was also associated with the activity of osteoblasts, cells in the bone responsible for synthesizing and mineralizing bone. Osteoblasts are also responsible for secreting collagen in order to create the unmineralized portion of the bone called the osteoid.*

Anecdotal evidence abounds of collagen's ability to increase hair and nail growth. More studies are needed, as research9 in this area has typically involved bovine or porcine collagen.*

Like bovine collagen, marine collagen really doesn't have many significant side effects.*

"As a functional medicine practitioner, one of the great things I have seen with marine collagen is how well it is tolerated by almost everyone," says mbg contributor William Cole, D.C..* "Where food reactivities are common today, this is one source of protein that not only agrees with most people but that people thrive taking."*

In some studies10, a few people have reported that it leaves a bad taste in their mouth, while others have reported minor bloating and digestive upset. But these results aren't the norm, and collagen is much more likely to help improve digestion than disrupt it. That said, you should definitely avoid marine collagen if you have an allergy to fish; and if you're currently taking any medication, check with your doctor to make sure collagen won't interfere with its effectiveness.

The best way to get collagen is through grass-fed bovine, as it contains both type I and III collagen, which are essential for full-body support.* If that is not an option, you still need to be mindful of where your marine collagen supplement is coming from.

"I always recommend people look for clean, wild-caught sources from a company that has independent nutritional and quality testing," says Cole. A good strategy is to seek out a product that has been third-party verified to contain what the label says it contains and to be free of contaminants like mercury and other heavy metals (reputable groups that test supplement ingredients include NSF International, USP, and UL).

Because marine collagen is typically derived from fish skin or scales, you should also consider where those fish came from—both for your health and the health of the environment. Ideally, you'll seek out a marine collagen supplement from an established company that sources their collagen from sustainably caught fish (if they don't call this out on their label, that's typically a red flag). A number of marine collagen products have also been non-GMO-Project certified, which is typically another indicator of a good product.