What You Should Know About Collagen

Sticking to the facts.

There is a new trend in the supplement and fitness industry: collagen. The name has a greek rooth: kólla means “glue” and the suffix -gen denotes “producing” as it was used in the past to produce glue out of skin and tendons of slaughtered animals. Now, it is either sold as a powder, hydrolyzed or undenatured, or as one of the components of bone broth and it should help against joint pain, autoimmunity, skin aging, gut issues and more. Even if a big part of the claims are exagerated as usual, there is a bit of truth behind. Let’s have a closer look at it.

what is collagen?

Collagens are a big family of fiber-building structural proteins in multi-cellular animal organisms. It is the main protein component of the connective tissue and the most abbundant protein overall in mammals, making up from 25% to 35% of the whole-body protein content. There are different types of collagen but all have a triple-helix structure in common, which is quite unique.

Triple helix structure of collagen

The five most common types are:

  • Type I: skin; tendon; vasculature; organs; organic part of bone
  • Type II: cartilage
  • Type III: reticular fibers, commonly found alongside type I
  • Type IV: basal lamina, a layer of the extracellular matrix secreted by the epithelial cells
  • Type V: cell surfaces, hair, placenta

Over 90% of the collagen in the human body is collagen type I, but in this article we will focus on collagen type II as it is the one which is sold as supplement for the treatment of joint pain and arthritic conditions.

collagen supplement forms and dosage

Remember that there is no non-animal source of collagen. That’s why it is not suitable for vegetarians and vegans. That said, there are basically two forms how collagen is sold as a supplement:

  • Hydrolyzed Collagen (also known as gelatin) is made from skin, bones and connective tissue mostly from shark and pork. Rarely, it is derived from bovine sources due to potential infection risk with bovine spongiform encephalopathy (Mad Cow Disease).  The collagen is irreversibly “cut” (=hydrolyzed) in smaller pieces, called peptides with a variable amino acid (=the brickstones of proteins) length. The active ones appear to be those with low molecular weight and are likely small peptides (like tripeptides) with a high amounts of glycine and proline, two amino acids that are prominent in collagen protein. Hydrolized collagen is taken in doses of around 10g a day for skin health and some benefits to joints, and can be taken with meals. 
  • Undenatured Collagen is non-hydrolyzed collagen that is still glycosylated. It is derived from chicken sternum and sold with the brand name UC-II®. It is adviced to take it at a dose of approximately 40mg once daily for the treatment of osteoarthritis and rheumatoid arthritis when there is an autoimmune component to it.

Proposed health benefits


It was fascinating for me to read that in regards to autoimmunity issues, such as rheumatoid arthritis, the ingestion of collagen already has an activity on cells of the immune systems located in the intestine, the so called dendritic cells of the Peyer’s patches. Dendritic cells are cells of the innate immune system responsible of presenting antigens (=molecules that may trigger an immune response) to the T cells of the adaptive immune systems. Doing so they have the capacity of activate a response against an antigen but also to form a tolerance to an antigen via influencing other immune cell populations such as T cells.

Already the ingestion of low doses of collagen seems to cause changes in the dendritic cells which promote T cells to differentiate into a more anti-inflammatory form, the T regulatory cells. T-regulatory cells reduce differentiation of T cells into T helper cells, which are responsible of activating B cells, cytotoxic T cells and macrophages, therefore potentiating the immune response. There is nothing wrong about T helper cells doing it in a healthy organism, that’s exactly their job! But in an autoimmune enviroment T- and B-cells are often a bit overzealous and promote an immune response against the body itself.

The T regulatory cells produce more of a messenger molecule called interleukin 10 (IL-10) which suppresses the actions of another molecule known as IL-17. Since IL-17 exacerbates rheumatism, increasing IL-10 concentrations reduces its actions and the subsequent joint pain.

Production of T regulatory cells from collagen is known as ‘tolerance’, which is achieved within a month of supplementation and can be continually held until supplementation is stopped where T cell populations and the two interleukins produced from them normalize about a month later resulting in symptoms recurring.


There are a couple of studies in mice (here , here and here) showing that the smaller peptides found in the hydrolyzed collagen supplements cross the blood-brain barrier and may mimic neurotrophines (proteins promoting survival, development and function of neurons) thus increasing neurogenesis (=growth of neurons) in parts of the brain. The mechanisms are largely hypothetical at this point and more research has to be done.

Bone and Joint Health

1. Collagen and Joints

We have already seen that in case of autoimmune arthritis, the supplementation of collagen seems to make sense. What about healthy subjects reporting joint pain? First you should know that also normal subjects have some degree of antibodies towards the body’s own structural collagen.

A study has shown that oral supplementation of undenatured collagen at 40mg a day (for four months) in patients with joint pain but without autoimmune arthritis was effective in improving knee range of motion compaired to the placebo group. They had also a longer time for joint pain to occur during exercise and faster recovery, maximal benefits occurring three months after supplementation and maintaining. However, the study could not show any influence on daily joint pain, which is assesed by the Knee Injury and Osteoarthritis Outcome Score (KOOS).

2. Ostheoarthritis

Osteoarthritis  is a type of joint disease that results from breakdown of joint cartilage and underlying bone, but has not a main autoimmune component. Causes are previous joint injury, abnormal joint or limb development, and inherited factors.

A study showed that oral supplementation of undenatured collagen from chicken sternum in osteoarthritic subjects at 40mg once daily over 90 days was effective (relative to baseline values) in improving different scores assessing osteoarthritic pain and mobility in a somewhat time dependent manner.

Another study was able to show that oral supplementation of 10g hydrolyzed collagen daily for six months in subjects with osteoarthritis was noted to reduce pain but failed to affect other parameters such as stiffness and function relative to placebo.

3. Rheumatoid Arthritis

See the paragraph about autoimmunity. Plus one more citation from Examine.com

Oral ingestion of solubilized type II collagen (0.1mg for one month, 1mg for two months) in subjects with severe active rheumatoid arthritis for 90 days appeared to improve symptoms on joints (swelling, pain, and tenderness) and preserved 15 minutes walking time relative to placebo which benefitted to a lesser degree with four subjects in the collagen group (14% of the sample) reporting resolution of rheumatism.

Kamal Patel – Examine.com


The collagen found in the extracellular matrix of the skin is mainly type I and to some degree type III collagen but a study in rats has found that type II collagen can still accumulate in the skin following oral ingestion of hydrolyzed collagen.

Nevertheless, the proposed mechanism of action of collagen as supplement for skin health is rather that oral ingestions increases serum levels of some dipeptides and tripeptides (chains of two and three aninoacids) of which one of them, proline-hydroxyproline (Pro-Hyp), can stimulate fibroblasts (cells in the extracellular matrix) to produce hyaluronic acid, also a component of the extracellular matrix (it binds water) and itself an oral supplement for skin health . Also chondrocytes, the cells producing and maintaining the cartilaginous matrix in the joints, seem to react with increased production of hyaluronic acid, which may explain some joint health properties.

bone broth

Bone broth has gained increased popularity as a health food, especially in the Paleo circles. The two most popular claims are that it has a high mineral content and it is also rich in collagen. Well, it seems that none of that is the case. An old study from the King’s College showed that most of the mineral content in the bone broth comes from the vegetables used and the collagen content as well as the amount of peptides/amino acids is quite low too, compaired to the supplemental sources .

Nevertheless, it is a healthy food even if it is not a magic potion. More than that, bone broth is a delicious staple giving a very rich, unique taste to home made soups, stews and sauces. What would a ramen without a proper broth be? Here is how to cook one:

  • buy some good quality bones from your butcher or use leftover bones from your roasts (chicken, duck, lamb…);
  • put them in a pot and cover them with cold water. Do not add salt. Eventually add some vinegar if you like it;
  • bring the water to boil and then let it simmer at very low heat for up to 48h;
  • use it immediately or store it in the freezer divided in portions as you need them.


There is still research to be done in regards to the efficacy of collagen agianst joint pain but in my eyes it is worth supplementing if you suffer from it, especially if it is of autoimmune nature. It does not replace a doctor nor a good physiotherapist designing you a proper exercise programm nor help you if your nutrition is crap and you are overweight but I think it could be a good support if you are already checking all the boxes.

You may also want to give it a try for skin health but again it is only the cherry on the top: if you expose yourself a lot to the sun without protection, smoke and your nutrition is based on processed junk food, do not expect wonders from collagen.

Bone broth isn’t a good source for collagen, your better served with hydrolyzed collagen or undenatured collagen, but you should definitely cook some if you want to level up your stews, soups and sauces.

Do you have any questions or did I miss some aspects? Do not be shy and drop your comment in the comment section below! Stay strong and healthy.

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