If you tune into nutrition in the media space, you've likely noticed collagen is all the rage right now. Thanks to brilliant marketing efforts from companies such as Vital Proteins, it's actually been the rage for quite some time. As a Registered Dietitian, I'm constantly getting asked about the efficacy of different supplements, and collagen is one of the more popular supplements I'm asked about.

It's time I dive deeper into the research to better understand the role of collagen in the body, as well as the scientific evidence of the benefits of collagen supplements, and I'm taking you with me! This blog post is pretty research heavy, but I kept it that way on purpose. It's important to understand the supplement industry is virtually unregulated, so we need to rely on evidence-based research to fully articulate the benefits of supplements, such as collagen.

So is collagen worth it or is it all just a hype?

What is Collagen?

Accounting for about 30% of your body's total protein, collagen is the most abundant protein in your body. It’s the main building block of connective tissues that make up several body parts, including tendons, ligaments, skin, and muscles. It helps provide structure to your skin and helps strengthen your bones.

Proteins are made from amino acids. The main amino acids that make collagen are proline, glycine and hydroxyproline. These amino acids group together to form protein fibrils in a triple helix structure. Your body also needs the proper amount of vitamin C, zinc, copper and manganese to make this triple helix.

Animal proteins are considered complete proteins, meaning they include all nine essential amino acids that cannot be manufactured in your body (aka you need to get them from food). Collagen does not contain the amino acid tryptophan, so it cannot be considered a complete protein.

However, many studies have shown that despite collagen's absence of tryptophan, it can still be counted towards your daily protein intake. This is similar to how we count plant-based foods, such as legumes and nuts, towards our daily protein intake despite those foods missing some essential amino acids as well.

You can get collagen from foods like bone broth and organ meats. However, bone broth and organ meats are not staples in most peoples diets, which is one of the reasons collagen supplements have become so popular.

Most collagen supplements are hydrolyzed, which means the collagen has been broken down to make it easier to absorb. These hydrolyzed formulas also dissolve nicely in beverages like coffee, making them easy to integrate into your daily routine. The types of collagen found in supplements vary — some contain one or two types, while others contain up to five.

What Are the Different Types of Collagen?

28 different types of collagen have been identified. The collagen types differ by how the molecules are assembled, the cell components that are added, and where the collagen is used in your body.

The main five types of collagen and what they do are:

• Type I. This type makes up 90% of your body’s collagen. Type I is densely packed and used to provide structure to your skin, bones, tendons and ligaments. This is the most common type of collagen you'll see in supplements.

• Type II. This type is found in elastic cartilage, which provides joint support. Only a limited number of collagen supplements actually contain Type II collagen.

• Type III. This type is found in muscles, arteries and organs.

• Type IV. This type is found in the layers of your skin.

• Type V. This type is found in the cornea of your eyes, some layers of skin, hair and tissue of the placenta.

How is Supplemental Collagen Absorbed in Our Body?

Some of my initial skepticism with supplemental collagen stemmed from my knowledge that collagen is a relatively large molecule. With my understanding of how nutrients are absorbed across our permeable intestinal membrane, I questioned if a large molecule like collagen could even be absorbed across the membrane. Further, if it's absorbed, does the body break it down further and then reabsorb it as collagen? Or is collagen just absorbed as a simple broken-down protein (aka amino acids) and therefore can't we just skip the expensive supplement and eat any source of protein?

After reviewing some of the research on collagen absorption, studies have shown that supplemental collagen can pass across the mucosal barrier in the small intestine as a complete peptide. Of note, a rat study concluded that 95% of collagen fed to rats was absorbed within 12 hours. This shows us that large molecules, like collagen, can be used whole by the body.

Once it enters the bloodstream, it then travels and accumulates in cartilage tissue, and stimulates production of type II collagen (the major protein in articular cartilage) and proteoglycans in the extracellular matrix of cartilage. In summary, this means that collagen is digested and signals to the body to make more collagen.

What Are the Benefits of Collagen?

Okay this is what we're all here for. Tell me all about the benefits of collagen supplements!

Bone Health

As people age, the body’s ability to produce collagen decreases by around 1% to 1.5% per year. Collagen appears to support bone health, as collagen is an essential component to bone mass. Collagen has also been shown to help with with bone mineralization, which is the process that strengthens and hardens bones.

Prevention and treatment of osteoporosis is an increasingly important public health concern because osteoporotic bone fractures are responsible for chronic pain, inactivity and invalidity in the elderly. It is estimated that, worldwide, every third women, and one in five men over the age of 50, will sustain an osteoporotic-induced bone fracture.

Current treatments for osteoporosis include non-pharmacological approaches, such as daily physical activity, smoking cessation, reduction of alcohol consumption, and supplementation with calcium and vitamin D.

Pharmacological treatment includes substances such as bisphosphonates, human monoclonal antibody therapy and selective estrogen receptor modulators. However, many of this pharmacological therapies come with unwanted side effects, including gastrointestinal disorders, hypocalcemia, or predisposed renal failure.

So can collagen be used as a non-pharmacological treatment without side effects to support bone mineral density?

Preclinical in vitro studies or investigations with rodents have shown that administration of collagen peptides increased the organic component of bones, improved bone metabolism, and enhanced the bio-mechanical resistance of vertebrae. Supplementation with collagen peptides in combination with calcitonin (a hormone that helps control the level of calcium in your blood) has shown positive effects in postmenopausal women.

A 2018 study investigated the effects of specific collagen peptides on bone health in 131 postmenopausal people with reduced bone mineral density. The researchers measured the effects of taking 5 grams of collagen peptides daily for 12 months, compared with a placebo group. They looked at changes in bone mineral density in the femoral neck, which is the area where the thighbone joins the hip bone and the spine.

The results showed the collagen peptides increased bone mineral density and improved bone markers, indicating a reduction in bone loss and an increase in bone formation. In other words, collagen may help mitigate further bone loss.

Given the results of the 2018 study, researchers followed up the study with another, smaller-scale study in 2021. It looked at the long-term effects of the same collagen peptides in 31 postmenopausal people. The participants were from the original study’s treatment and placebo groups.

Researchers found that a daily intake of 5 grams of collagen peptides over 4 years significantly increased bone mineral density. Participants also experienced no fractures during the 4-year period.

While research on collagen and bone health is somewhat limited, the research we do have is strong and promising!

Joint Pain

As a long distance runner, endurance junky, and someone with a history of chronic Lyme disease, I've always been curious about collagen's ability to relieve joint pain.

One study noted that athletes who consumed collagen over the span of six months experienced improvement of joint pain. After 3 months of taking 10 grams of collagen per day, athletes reported less pain and greater ease of climbing stairs and carrying objects.

To control for alternative joint pain management and therapy, such as topical ice and heat, acupuncture, or medication, alternative therapies were recorded and collected throughout the duration of the study. At visit five during the study, the group taking collagen hydrolysate reported using alternative therapies 12 times, while subjects taking placebo reported using alternative therapies 39 times. This study outcome indicates subjects taking collagen reported less joint discomfort than subjects taking placebo.

Collagen has been extensively studied as a potential osteoarthritis treatment. Research quality varies, but most findings are positive.

One small observational study found that a hydrolyzed collagen supplement significantly reduced pain and stiffness in people with knee osteoarthritis. Patients were only followed for a month, however, and there was no control group.

A more robust randomized trial compared 40 mg a day of Type II collagen supplement to a placebo group. After six months, people taking the Type II collagen supplement had significantly less pain and stiffness and better function than did the placebo group.

Further, an analysis of 41 animal and human studies, including 25 clinical trials, found that collagen benefited osteoarthritis and aided cartilage repair, no matter what the dose, type or brand of collagen. 

All of this evidence is pretty compelling and suggestive that collagen may be a supportive therapy for managing joint pain. It's also interesting to think about which types of collagen may be most beneficial for joint pain. For example, from the research summarized above, it appears supplements with Type II collagen may be the most supportive for managing joint pain.

Skin

The benefit to skin with collagen supplementation is what I most often see advertised in the media, so again, I was very curious to see what the research tells us regarding skin health and collagen supplementation.

Collagen hydrolysate is a well-known dietary supplement for the treatment of skin aging, however its mode of action remains unknown. Previous studies have shown the oral ingestion of collagen hydrolysate leads to elevated levels of collagen-derived peptides in the blood. It's still unclear whether these peptides reach the skin when ingested orally.

A study analyzed the plasma concentration of collagen-derived peptides after ingestion of high tri-peptide containing collagen hydrolysate in humans. They identified 17 types of collagen-derived peptides, with a particular enrichment in Gly-Pro-Hyp. This was also observed using an in vivo mouse model in the plasma and skin, albeit with a higher enrichment of Pro-Hyp in the skin. Interestingly, this Pro-Hyp enrichment in the skin was derived from Gly-Pro-Hyp hydrolysis, as the administration of pure Gly-Pro-Hyp peptide led to similar results.

That was a lot of science jargon, so here's the major takeaway of this study: collagen can reach the skin when ingested orally.

The unique amino acid profile of collagen may be responsible for the observations of orally administered collagen effects on skin physiology. A study demonstrated that the “ingestion of collagen peptide (0.2 g/kg/d) suppressed UV-B-induced decreases in skin hydration, hyperplasia of the epidermis, and decreases in soluble type I collagen.” This suggests that collagen is beneficial as a dietary supplement to suppress UV-B-induced skin damage and photoaging.

Another study related collagen consumption to better skin ulcer healing. Those who received the collagen supplement had twice the rate of pressure ulcer healing by the eighth week of treatment.

For those who don't work in a hospital setting, you may not know how common wounds like pressure ulcers are among certain patient populations. I have seen some pretty terrible pressure ulcers on patients who are bedridden. Thank you to all the wound care nurses out there! You're the real heroes!!

As a clinical Registered Dietitian, I typically have the medical team check for vitamin and mineral deficiencies and almost always recommend a high protein supplement, vitamin C supplementation, and potentially a specialty supplement called Juven, which contains wound-healing nutrients including glutamine, arginine, collagen, zinc, vitamin C, and vitamin B12. These nutrients have been extensively researched to be supportive of pressure ulcer healing.

Collagen is also thought to attract water molecules, in turn improving skin hydration, scavenge free radicals and reduce inflammation. A study investigated 20 healthy women ingesting 10 grams of collagen daily. They saw gradual improvement of water absorption capacity compared to the placebo group. The water content of the dermis increased by 14% at week 6 from the baseline value in the group ingesting collagen daily.

Another study investigated the effect of a dietary supplement containing a hydrolyzed collagen type II, hyaluronic acid and chondroitin sulfate in 26 healthy females who displayed visible signs of natural and photoaging in the face. Daily supplementation with just 1 gram of hydrolyzed collagen for 12 weeks led to a significant reduction of skin dryness/scaling and global lines/wrinkles. An increase in the content of hemoglobin and collagen in the skin dermis was also observed after 6 weeks of supplementation.

The authors suggested that dietary supplementation with hydrolyzed collagen can physiologically counteract natural and photoaging processes to reduce visible aging signs in the human face. This study shows that an oral nutritional supplement consisting of hydrolyzed collagen, hyaluronic acid, and essential vitamins and minerals, leads to a significant improvement in wrinkle depth. It is also able to induce noticeable improvement in elasticity and hydration of the skin.

Okay, so maybe we're onto something with collagen supplementation and skin health!

Hair

I'll be honest, luxurious, silky, smooth, and long hair is something I've always desired! After going through treatment for chronic Lyme disease, I noticed my hair was not as healthy as it used to be. This was likely due to being in a perpetual state of inflammation and I was malnourished due to the inability to adequately tolerate certain foods. Now that my health is in a better place, I've also noticed improvements to my hair.

So can collagen give my hair a further boost?

Unfortunately, studies on the effects of collagen and hair health are limited. What we do know is that collagen is a protein, and hair is largely made up of a protein called keratin. Therefore, collagen may provide the amino acids necessary to build keratin and promote hair growth. Based on the lack of research, it's unknown whether it's the increase in protein from collagen ingestion or the collagen itself that is supporting hair growth and health.

Based on the lack of human research related to hair growth and collagen supplementation, I wouldn't choose to supplement with collagen solely for the benefit of hair growth at this time.

How Much Collagen Should I Take?

This is going to be somewhat bio-individual based on your goals. The dosing guidelines in the research vary based on what your intended use of collagen is. Are you trying to evade wrinkles? Are you trying to escape joint pain as a distance runner? Are you trying to hydrate your skin while living in a frozen tundra (me!)?

In the research I cited throughout this blog post, the collagen dosages varied. However, most of the research suggests ingesting anywhere from 10 grams to 20 grams of collagen daily may be beneficial. Most products provide this dosage range.

If you're looking for more joint pain relief, I suggest finding a collagen supplement that is rich in Type II collagen, and combining it with a source of vitamin C. I've recently started taking a product from the company Modere called Liquid BioCell Life, which includes vitamin C and Type II collagen with the hope it can support my joint pain as an endurance athlete. Before I recommend the product to anyone, I'm doing my own little trial.

If you're looking for more skin health benefits, perhaps a product that contains more Type I collagen is sufficient. However, based on the research and my professional opinion as a Registered Dietitian, a product that contains both Type I and Type II collagen is going to give you the most "bang for your buck." Who wouldn't want skin benefits AND more joint pain relief?!

The Major Takeaway

To conclude, after my extensive review of the research, I'm pretty pro-collagen. The research is especially compelling related to bone health, joint pain and skin health, but is still lacking related to hair health benefits.

This research also highlights that introducing collagen-rich foods to your diet can't hurt either. Sipping on some bone broth can be incredibly healing!

References:

Broumand, M. & Sibilla, S. (2015). Effects of a nutritional supplement containing collagen peptides on skin elasticity, hydration, and wrinkles. Journal of Medical Nutrition and Nutraceuticals, 4(1), 47.

Clark, K.L., Sebastianelli, B., Flechsenhar, K.R., Aukermann, D.F., Meza, F., Millard, R.L., Deitch, J.R., … & Albert, A. (2008). 24-Week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain. Current Medical Research and Opinion, 24(5), 1485-1896. doi: 10.1185/030079908X291967

de Almeida Jackix, E., Cuneo, F., Amaya-Farfan, J., Viera de Assuncao, J., Quintaes, K.D. (2010). A food supplemenent of hydrolyzed collagen improves compositional and biodynamic characteristics of vertebrae in ovariectomized rats. Journal of Medicinal Food, 13(6), 1-6). doi:10.1089=jmf.2009.0256

Hwang SB, Park HJ, Lee BH. Hair-Growth-Promoting Effects of the Fish Collagen Peptide in Human Dermal Papilla Cells and C57BL/6 Mice Modulating Wnt/β-Catenin and BMP Signaling Pathways. Int J Mol Sci. 2022;23(19):11904. Published 2022 Oct 7. doi:10.3390/ijms231911904

König, D., Oesser, S., Scharla, S., Zdzieblik, D., & Gollhofer, A. (2018). Specific Collagen Peptides Improve Bone Mineral Density and Bone Markers in Postmenopausal Women-A Randomized Controlled Study. Nutrients, 10(1), 97. https://doi.org/10.3390/nu10010097

Lugo, J.P., Saiyed, Z.M., & Lane, N.E. (2006). Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: A multicenter randomized, double-blind, placebo-controlled study. Nutritional Journal, 15(1).

Tanaka, M., Koyama, Y., & Nomura, Y. (2009). Effects of collagen peptide ingestion on UV-B-induced skin damage. Bioscience, Biotechnology, and Biochemistry, 73(4), 930-932. doi: 10.1271/bbb.80649

Zague, V. (2008). A new view concerning the effects of collagen hydrolysate intake on skin properties. Archives of Dermatological Research, 300, 479-483. doi: 10.1007/s00403-008-0888-4

Yazaki, M., Ito, Y., Yamada, M., Goulas, S., Teramoto, S., Nakaya, M.A., Ohno, S., & Yamaguchi, K. (2017). Oral ingestion of collagen hydrolysate leads to the ptransportatino of highly concentrated Gly-Pro-Hyp and its hydrolyzed form of Pro-Hyp into the bloodstream and skin. Journal of Agricultural and Food Chemistry, 2017. doi: 10.1021/acs.jafc.6b05679