Collagen Supplements—Should You Take Them?

As a dietitian, I field a lot of questions about certain diets, foods, and supplements. If I get enough questions about a specific topic, I feel it’s worth covering in a blog post. Doing so is a great opportunity for me to conduct a thorough literature review, and the end product provides an up-to-date, evidence-based review for my friends, family, and followers. The last topic I covered was the keto diet (see here), and now I’ll focus on the current food trend du jour: collagen supplements.

Search the internet for information on popular nutrition trends and you’ll find all sorts of articles with extraordinary claims that make it seem like a certain diet or supplement is a cure-all for any and every ailment you may have. And while these articles are intriguing, it’s important to look at the science behind the claims to see if they hold any water. So, let’s take a look at the science behind collagen supplements, starting with the basics.

What is collagen?

Collagen is a protein found throughout the human body. It’s been called “the body’s scaffolding,” as it’s the main structural protein for various connective tissues, which hold our body together. There are over 20 different types of collagen, which vary in how hard or soft they are. For example, collagen can be found in bone, where it’s more rigid, or it can be found in tendons, ligaments, and blood vessels, where it’s more compliant. Collagen is also found in cartilage, corneas, intestines, hair, skin, and placentas.

Your body makes all the collagen you need, and it will continue to do so for the rest of your life (although there are some rare genetic connective tissue disorders that impair collagen production). Yet as we age, collagen production gradually declines, which is a normal, natural, and inevitable part of aging. This decline, though, creates an opportunity for companies to sell us a “cure.”

Enter collagen supplements

Interestingly, humans can’t digest or absorb whole collagen. This is why supplement companies have to chemically or enzymatically hydrolyze (break down) collagen into smaller amino acid peptides. These supplements are derived from animal tissue rich in collagen, such as tendons, ligaments, cartilage, intestines, skin, corneas, and more. We have no way of determining where the protein from these supplements will go, or how it will be used in our body. Once digested and absorbed, collagen protein enters our body’s amino acid pool, and our body will allocate it, along with any other protein we consume, where it deems appropriate. So the claim that collagen protein is directly deposited into our skin, joints, or any other area is inaccurate.

Other sources of collagen

In addition to supplements, there are some food sources that contain collagen. Tendons, ligaments, or other collagen-containing tissue obviously contain collagen. But remember, we can’t digest or absorb this form, so consuming it this way is useless.

Another source is bone broth, which has been made popular by fad diets such as the paleo and keto diets. This gelatinized form of collagen differs from hydrolyzed collagen, so our ability to digest, absorb, and use it is questionable. That doesn’t stop bone broth proponents from making all sorts of bold health claims about how amazing it is for you. Unqualified bloggers and health writers claim it can cure everything from a leaky gut to thyroid diseases to autoimmune disorders. If these claims sound too good to be true, it’s because they are. There are virtually no human studies to support any of these claims. On the contrary, bone broth may actually be harmful.

Bone sequesters heavy metals that leach out when cooked, such as lead and cadmium. Commercially tested bone broth products have been shown to contain “markedly high lead concentrations,” although levels appear to vary depending on the brand and cooking methods (1-2). Either way, the Center for Disease Control and Prevention, the Environmental Protection Agency, and the World Health Organization all agree that there is no safe level of lead in our body, especially for children (3). When it comes to bone broth, the risks far outweigh the non-existent benefits, so avoid consuming it.

But what about collagen supplements?

Below are the most common health claims surrounding collagen supplements. Let’s see if there’s any evidence to support them.

Improve skin health. There have been a handful of studies looking at collagen supplementation and skin health (skin elasticity, hydration, and wrinkles) (4-11). These are small studies often published in little-known journals, but they do tend to show a small benefit. Unfortunately, the most suspicious aspect of these studies, is who funded and/or conducted them. If you look at the author’s affiliation or funding source, you will find names like: Minerva Research Labs Ltd; Collagen Research Institute; and BioCell Technology, LLC. Guess what these companies sell? Collagen supplements! Keep in mind there is no FDA oversight of supplements or the health claims made about them, so these companies can do and say whatever they want. But as NYU nutrition professor Marion Nestle—who literally wrote the book on food politics—has pointed out, industry-funded studies are more about marketing than they are about science. Considering I couldn’t find any legitimate non-industry funded studies looking into the subject, the jury is out on whether or not collagen supplements have any effect on our skin health. What is known, however, is that smoking tobacco, drinking alcohol, and excessive sun exposure is detrimental to skin health and promotes skin aging. Focus on avoiding these instead of buying collagen supplements.
Relieve joint pain. Similar to skin health, many of the studies and reviews looking into collagen supplements for joint pain are small, short in duration, published in little-known journals, and are often funded by companies selling collagen supplements (12-22). Despite this, if we take the evidence as it is, the argument that collagen can reduce joint paint is not very convincing. A 2018 systematic review and meta-analysis published in the British Journal of Sports Medicine came to the same conclusion stating that although a few short-term improvements have been reported, “supplements had no clinically important effects on pain and function at medium-term and long-term follow-ups.” Based on the available data, it is unlikely that collagen supplements will relieve joint pain.
Provide a bone boost. Websites stating that collagen can “prevent bone loss,” or “improve bone density” often provide no supporting data. When pooling the references that are occasionally provided from these websites, along with other studies I found on the subject, we get a hodgepodge of data. Similar to studies looking at skin health or joint pain, these studies are small in size, short in duration, published in little-known journals, typically funded by collagen-selling companies, and typically show no benefit compared to a placebo, or the studies are conducted on rodents (23-27). Based on the available data, it is unlikely that collagen supplements will improve bone health.
Can increase muscle strength and mass. There is simply no good data to make this claim. Yet that doesn’t stop bro-science websites from stating that “collagen can help you build bigger and stronger muscle.” These websites often point to a 2015 study published in the British Journal of Nutrition (28). This study was funded by Gelita, a company that sells collagen supplements, and was conducted by researchers from the Collagen Research Institute. It followed the classic design that many protein supplement companies use to make their product seem useful—take an elderly population that doesn’t consume enough protein at baseline, give half protein supplements and the other half a placebo. Surprise-surprise, they find that supplementing protein in a protein-deficient population leads to a few small benefits. The few other studies looking at collagen supplements and muscle strength were conducted on rodents or exploit a similar elderly population (and were also funded by companies selling collagen supplements) (29-30). Interestingly, collagen is the only true “incomplete” protein in the human diet, as it does not contain tryptophan—an essential amino acid found in varying amounts in all other food. For this reason, many consider it the worst source of protein we could choose from.
Weight loss. I was unable to find any studies looking at collagen supplements and weight loss. A couple of studies have looked at the satiating effect of collagen, but they are of poor quality and cannot be used to claim collagen will help with weight loss (31-32). To date, there is no evidence that I could find suggesting that collagen supplements lead to weight loss.
Improve digestion and gut health. There are absolutely no legitimate studies to support this claim. Advocates for collagen often report that it can “heal leaky gut,” but provide no evidence to support it.
Better hair and nails. The only study I could find (surprise, surprise) was conducted by the Collagen Research Institute (33). Like many of these studies, they are of extremely poor quality and often lacking a control group. Once again, no convincing data to support claims that collagen supplements will improve hair or nail health.
Brain health. A couple articles have discussed the role of collagen tissue in brain health (one was in mice), but no studies have actually put it to the test (34-35). So once again, no convincing data to support this claim.
Reduce cellulite. I could only find one study on this subject, which was funded by Gelita and conducted through the Collagen Research Institute. Despite the funding, they found that collagen supplements resulted in no significant improvement of cellulite compared to a placebo (36).
Heart healthy. I could only find one study that looked at collagen supplements and cardiovascular risk factors. This was conducted by researchers from Jellice—a company that sells collagen supplements—and found no noteworthy benefits (37). Again, this study was of poor quality—no control group, no placebo, and the potential for numerous confounding factors. You’re better off eating a whole food, plant-based diet for heart health.

Anytime a new supplement hits the market, it should be considered ineffective until proven effective by multiple, independently-funded human studies published in peer-reviewed journals. Unfortunately, the current situation is just the opposite—supplement companies can do and say whatever they want, as there is no FDA oversight. It’s only when unsafe or contaminated supplements start killing people that they are pulled from the shelf.

It wouldn’t surprise me to see claims that collagen supplements can cure cancer, solve world hunger, or help you win the lottery. I realize I sound like a broken record in the topics above, but evidence to support the health claims made about collagen supplements is extremely weak or completely non-existent. Not to mention, nearly all of the research was funded by companies selling collagen supplements. Which again, is more about marketing than it is about science. We wouldn’t use tobacco industry studies to determine whether or not cigarettes are good for us and we shouldn’t do the same for collagen, or any other food/supplement for that matter.

More importantly, let’s not forget that our body makes all the collagen it needs. There are, however, certain nutrients that serve as co-factors in collagen synthesis. Being deficient in these could result in impaired collagen synthesis. The most important of these is vitamin C. Good dietary sources of vitamin C include, peppers, strawberries, papaya, broccoli, brussels sprouts, pineapple, oranges, kiwi, cantaloupe, cauliflower, guava, mango, grapefruit, and avocado.

Zinc and copper are also important for collagen synthesis. Healthy sources of zinc include, wheat germ, sesame seeds, pumpkin seeds, lentils, garbanzo beans, cashews, quinoa, all types of beans/legumes, oatmeal, and almonds. Healthy sources of copper include, sesame seeds, cashews, soy products, mushrooms, sunflower seeds, beans, lentils, walnuts, potatoes, dark chocolate, avocado, millet, spinach, figs, as well as most nuts and seeds.

Bottom line, there is simply no convincing evidence to support any of the health claims surrounding collagen supplements. If you’re eating a nutrient-dense diet rich in vitamin C, you’re likely making all the collagen you need. In other words, you’d be better off taking the money you were going to spend on collagen supplements, and heading over to the produce section. In plants we trust!

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