- What is collagen and why do we need it?
- How well is collagen absorbed?
- Hydrolysed collagen supplements
- The evidence for collagen supplements for skin
- Nutritional alternatives to collagen supplements
- Key takeaways
Whether or not collagen supplements “work” is one of the most contentious issues in medical aesthetics. Can collagen pills and powders really make a difference for skin and gut health, or does the body simply break down the protein into its individual amino acids like it does with any other protein?
What makes collagen supplements so special, if anything? And can different types of collagen peptides have different effects on health?
Let’s dig in and look at the evidence for and against collagen supplements. First, a quick reminder as to what collagen is and why it’s important in human health.
For a unique take on the wisdom of taking a collagen supplement, you might also want to check out this episode of the Gene Food podcast.
What is collagen and why do we need it?
Collagen is the main type of structural protein in the body, accounting for around 75% of the dry weight of the skin and playing a major role in bone health and most other tissues in the body. Collagen provides the scaffolding for harder structures like bones and teeth, and for cartilage, viscera, and organs. It holds moisture to keep tissues firm and plump and plays a part in protecting the skin against damage from ultraviolet radiation.
Collagen synthesis starts to decline rapidly around the age of 30, which can lead to thin, sagging, dry, wrinkle-prone skin, weaker joints and bones, and slower healing, among other things. The thinking behind collagen supplements, then, is that these can help boost the amount of collagen in the body to help slow or even prevent or reverse this decline. Some of the purported benefits of collagen supplements include:
- Reducing deep wrinkles and fine lines around the eyes
- Improving skin elasticity and density
- Enhancing skin smoothness, for a more youthful appearance
- Promoting endogenous (internal) collagen production and elastin production (elastin is the “elastic” protein that gives skin its “bounce”)
- Reducing the appearance of cellulite
- Supporting the health of blood vessels
- Supporting joint and bone health and reducing pain associated with osteoarthritis
- Helping to heal the gut / microbiome
These all sound like great benefits from a single supplement, but is there any real evidence to support these claims?
How well is collagen absorbed?
Collagen is a large protein, with an average molecular size of about 300 kilodaltons (kD). This means that when we ingest collagen, such as from meat or bone broth, it is too large to pass directly through the gut wall. Instead, like most proteins, the digestive system uses proteolytic enzymes to break down the protein into individual amino acids or smaller chains of these amino acids (peptides) that can pass through the gut wall and, eventually, make it into the bloodstream.
See also: Can undigested protein cause leaky gut?
Why take collagen supplements then? Well, even poor-quality collagen supplements provide extra protein with a specific ratio of ready-made amino acids necessary for collagen production. The main amino acids in collagen are proline and glycine, with proline combining with the amino acid lysine to form hydroxyproline. There’s no guarantee, though, that the body will digest the collagen and assign the resulting amino acids or peptides to form new collagen, but it is possible and the body can always use these amino acids to produce other important proteins.
As an added benefit, the amino acids in collagen are not the amino acids thought to promote aging (BCAAs, methionine, tryptophan) in the research of Dr. Walter Longo, head of longevity at USC.
Hydrolysed collagen supplements
Due to the problems with absorption, manufacturers have developed novel techniques that dramatically reduce the molecular size of collagen to a point where it can be absorbed intact through the gut wall. Instead of 300 kD, some hydrolysed collagen supplements have a molecular size of just 3 kD, which is extremely tiny and essentially “predigested” for immediate absorption.
Time for another caveat, though: even when hydrolysed collagen is absorbed, there’s no guarantee that it will go where any given individual wants it to go. Say a person takes a collagen supplement because they want to get rid of crow’s feet around their eyes, the body may well have other designs on that collagen and send it instead to help with joint or bone health. The fact is that the body almost always puts the skin last on its list of priorities and will instead favor internal health.
Of course, you could view the body’s smart prioritizing as another reason to use collagen supplements: if there are already outward signs of collagen degradation (wrinkles, cellulite, etc.), this may indicate internal problems affecting overall collagen production with negative consequences for cardiovascular health, joint health, and bone strength.
Providing the body with ready-made collagen and letting it do its thing could, therefore, have unexpected benefits for joint health and cardiovascular health.
The evidence for collagen supplements for skin
There’s plenty of anecdote to support the use of collagen supplements for skin health, but just a handful of decent quality studies that suggest benefits.
Double-blind studies in Germany, for example, have looked at the effects of 2.5-5 grams of animal-derived hydrolysed collagen in women aged 35-65 over eight weeks. Those who received the collagen rather than the placebo were assessed as having improved skin elasticity, moisture, and roughness, as well as less transepidermal water loss (which leads to dry skin), with women aged 45-65 enjoying a significant reduction in eye wrinkle volume (of 20-50%).1
In another double-blind, placebo-controlled clinical study, women aged 24-50 with moderate cellulite who took 2.5 g of bovine collagen peptides for six months were deemed to have a significant decrease in cellulite and reduced skin waviness on their thighs, compared to women taking a placebo.2
The problem with most collagen studies is that they are methodologically flawed. They tend to rely on subjective assessments of wrinkles and do not account for dietary factors, such as intake of protein and vitamin C. And, as for animal studies, these are especially flawed, given that rats and mice have significantly faster metabolisms and different enzymatic activity.
Collagen benefits for osteoarthritis patients
Several studies have focused on other, more easily measured, potential benefits of collagen, however. For example, some research suggests that hydrolysed collagen may support cartilage formation and help reduce pain from osteoarthritis. In one review, collagen hydrolysate was deemed to be well absorbed orally, to accumulate in cartilage, and to stimulate cells called chondrocytes to produce new connective tissue. This review also noted that collagen supplements have been associated with significant reductions in osteoarthritis pain and improvements in function compared to placebo.3
In one study, people with knee osteoarthritis who received 10 grams of type 2 collagen alongside 1500 mg of acetaminophen daily for three months had greater improvements in walking scores compared to those just receiving the acetaminophen. Both groups had improvements in joint pain, function, and quality of life.4
Collagen benefits for athletes
Collagen supplements have also been associated with some benefits for athletes, which makes a certain kind of sense given that active bodies need additional protein to build and maintain strong and healthy muscles and joints. In one study, 24 weeks of hydrolysed collagen (10 g/day) supplementation was associated with significant benefits for joint pain compared to placebo in students on varsity teams or in sports clubs.5
Collagen benefits for people with bone disorders
These probable benefits of collagen supplements for bones and joints makes sense because certain bone disorders have a collagen connection. Osteoporosis and osteopenia, for instance, are connected to problems with specific genes that influence collagen cross-linking via lysyl hydroxylase and lysyl oxidase-mediated enzymatic processes, as well as abnormal levels of LH2b cause defective cross-linking patterns and collagen fibrillogenesis, and abnormal mineralization of bone.67 As an example, the condition Bruck syndrome type II is characterized by less resilient cross-links in bone and connective tissue, which reduces the body’s ability to properly mineralize bone, making bones more vulnerable to micro-damage and, eventually, fracture and pain.8
While there are certainly many caveats and a lack of robust evidence for skin benefits of collagen, there is some support for the use of collagen in joint health. So, if you do choose to use collagen supplements, what should you look for? And what might be a good alternative to collagen?
A note on collagen for vegans and vegetarians
Collagen is a protein found in abundance in animals. As such, collagen supplements are currently sourced almost entirely from animals. Commercially viable plant-based collagen supplements do seem to be on the horizon, but are not yet available for the general consumer. There has been some success in the laboratory in creating plant-based collagen for use in skin grafts, but as of the time of writing I’ve not seen any collagen supplements made from plant sources. As a vegan in my 30s, I’m excited to see some solid science on these before forking over any cash.
In the meantime, vegans, vegetarians, and anyone skeptical of the absorbability of collagen supplements can easily provide their body with the building blocks for collagen.
Nutritional alternatives to collagen supplements
Collagen is made up of three main amino acids: proline, glycine, and lysine (which forms hydroxyproline).
L-lysine and collagen production
Lysine is an essential amino acid, meaning that the human body cannot make it itself. If you tend to suffer from canker sores (cold sores) caused by the Herpes simplex virus, it’s likely that you’re lacking lysine. This may also mean that your body is fighting to create enough collagen to keep your skin, organs, and other tissues healthy. In such cases, the best option may be to take a daily lysine supplement (1000 mg or so) with added vitamin C.
Vitamin C and collagen
Vitamin C is essential for healthy collagen production, as demonstrated by the disease known as scurvy. For centuries, this condition plagued sailors who spent months at sea without seeing a fresh fruit or vegetable. The resulting vitamin C deficiency meant that their bodies could not properly hydroxylate collagen, meaning that the collagen that was produced was misshapen and weak: The sailors bodies would quite literally fall apart.
Bring on the limes! Smart captains soon learnt that giving their crew limes could help prevent scurvy, although it would still be many years before vitamin C itself was discovered.
The importance of vitamin C for collagen production also underlies another factor in visible signs of aging, namely smoking. Every cigarette smoked uses up around 50 mg of vitamin C. That vitamin C is, therefore, no longer available for use in collagen production. Smoker’s lines are a clear sign of collagen degradation, and people who smoke tend to have much thinner, fragile, dry, and unhealthy skin. Now consider what this lack of collagen is doing internally. Clearly, stopping smoking is the smart move for skin health and overall health. At a minimum, though, anyone who smokes should up their vitamin C intake accordingly.
As for the other factors in collagen synthesis, glycine is the simplest of all of the amino acids and, like proline, can be synthesized in the body. It is unlikely that glycine or proline deficiency will arise and lead to a decline in collagen synthesis, except in cases of extreme malnutrition and protein deficiency. Poor collagen synthesis is much more likely to be a result of low levels of lysine, vitamin C, and other co-factors in collagen production such as copper and iron.
Many collagen formulas, such as Collagen Plus, now include these co-factors, recognizing their importance for collagen synthesis in the body. Some formulas also include hyaluronic acid, which has an impressive capacity to hold water and maintain skin hydration. Hyaluronic acid is poorly absorbed, however, and, like collagen, doesn’t necessarily make it to the skin even when it is absorbed.
All in all, the smart move is probably to focus on getting all the building blocks of collagen in the diet, including sufficient protein; maintaining good levels of hydration; minimizing things that damage collagen, such as smoking, sun exposure, and pollution; and avoiding chronic stress and unhealthy dieting practices that increase cortisol and disrupt hormone synthesis and overall health.
Do you have a collagen supplement you enjoy? Share with us in the comments!