Collagen 101

Collagen is all the rage at the moment, so I thought it would be a good time to highlight this magical substance and give you the in’s and out’s of one of my favourite “supplements”. I’ve been taking collagen peptides powder and drinking bone broth religiously for well over three years now, and I truly love the stuff. There are so many ways to naturally boost your body's collagen production- but since our body's ability to make it declines with age, a reliable collagen supplement is like the secret fountain of youth. 

Collagen proteins are an integral part of being a human being, because they are literally the substance that a large part of our skin suits are made of. Protecting (and boosting!) it will ensure you age gracefully, promote healthy joints, bones, gut, and generally support the health of your meat vehicle.

When you hear the word collagen you might think to yourself cosmetic surgery, and I am here today to tell you there are less foul ways of supporting your body's natural aging process- without injecting or cutting yourself open. At the end of the day- you do you, but plastic surgery befouls me; I am so against the concept in general- not only the harm it can do to the body, but the distress it has on the mental psyche. I love my body, I am so grateful for the gift of this human life- and I am definitely one to support my body naturally to help it thrive and age with grace.

This article highlights collagen supplements, but also natural ways to boost your body's own production, things to avoid that destroy collagen, and many other topics, all in the format of a Q&A. Links to supplements I discuss will take you to the Vital Proteins website, a company I  trust and am now working with as an affiliate. There are many brands of collagen out there, and it is so so important to invest in a high quality, pasture-raised, organic supplement. If a collagen powder supplement is out of your budget, there are many other ways to naturally boost your body's collagen production, so read on!





noun: collagen; plural noun: collagens

Any of a group of fibrous proteins that occur in vertebrates as the chief constituent of connective tissue fibrils and in bones and yield gelatin and glue upon boiling with water.


There are actually over 20 types of collagen (creatively named collagen 1, collagen 2, collagen 3, etc); but all you should really concern yourself with are the principle types 1, 2, and 3- that make up the majority of your body's collagen needs. Type 1 in particular is what gives structure to skin, tendons, bones, and organs- this is the kind that makes your hair, skin, and nails grow and glow. It also heals the gut, and speeds up wound healing. Type 2 is more about cartilage and joint health, this type of collagen supports cracking knees, back, and jaw pains. Type 3 is made of reticular fibers and a major component of that makes up your organs and skin. 90% of the body's collagen is types 1 and 3, and in supplement form, these two types often go hand in hand (more on this later). Bovine collagen is made up mostly of types 1 and 3, while chicken collagen is made up mostly of type 2. Marine collagen (from fish) is said to be the most bioavailable, and is made up mostly of type 1. Don't concern yourself too much with this, any (high quality) collagen powder supplement will do wonders for your body- and I'll get into some of my favourite products below.


I asked you guys for any questions you have regarding collagen, and it essentially covers the whole subject top to bottom.. so let's live in!


Collagen Q&A


Well this gets right to the point! Let's break it down.



Collagen is found abundantly in our muscles, tendons, joints, bones, skin, blood vessels, digestive system, skin, hair, nails. The word collagen actually comes from the Greek word "kolla" (meaning glue), and indeed it essentially is the gelatinous substance that holds our skin suits together! This stuff is important not only when you're "young"- as it helps repair the body (from cuts, exercise recovery, leaky gut etc), but even more so as we age. I like to think of collagen as a fountain of youth- because it support elastic, plump skin, as well as supports healthy bones and joints. Ain't nobody got time for brittle bones! Despite being nearly 28, I often get mistaken for a 16 year old (no joke), and collagen-boosting habits (as well as supplements) are an integral part of my long-term plan to look and feel vibrantly alive. 

Our collagen production drops at a rate of 1% after the age of 20, so being mindful of ways to support your body as its ability to produce collagen naturally slows down will help your body thrive as it ages. There are many studies showing the incredible impact of collagen on a multitude of bodily functions. One of the most mind blowing for me is to see wrinkles diminish by 20% in an 8 week study- not even for the vanity aspect, but truly to see the skin come back alive! Links to studies at the bottom of this article.



Collagen is produced endogenously by our bodies but can alsobe boosted with a particular diet, and habits. 

“You can’t out train a bad diet” mirrors the fact that you can’t "out-diet" your bad habits when it comes to boosting your body’s collagen production. So before worrying about putting in the good- be mindful of removing the bad.


Collagen Killers

Excess sugar molecules that we consume attach to collagen and elastin fibers in skin, causing them to harden and become more fragile and prone to damage.
— Dr. Fredric Brandt, M.D., a cosmetic dermatologist and founder of the Dermatology Research Institute in NYC
Do you know whats REALLY in your skin/ body care? Click image to learn more about the importance of trustworthy skincare products, and my favourite brands.

Do you know whats REALLY in your skin/ body care? Click image to learn more about the importance of trustworthy skincare products, and my favourite brands.

  1. Refined sugar. Too much sugar essentially ages your skin through a process called glycation, whereby sugar binds to collagen and over time destroys the density of elastin and collagen. Moreover, sugar also promotes inflammation and breaks down antioxidants- leaving you more susceptible to things like sun damage (and further collagen depletion).

  2. Smoking. When it comes to smoking, a restriction of blood flow means a drop in collagen too. Smoking has a host of harmful effects, and deepAF wrinkles are definitely one of them.

  3. Sun Smart. Sun is an absolute wonder for your body and a necessary part of any thriving humans existence- but over exposure is a one way ticket to collagen destruction. Your skin does need bare exposure to sunlight to synthesize vitamin D (and a host of other benefits, including promoting strong bones) but too much (and especially a sun burn) will destroy your skins collagen.

  4. Caffeine and Alcohol. To learn more about why caffeine is not your friend, read THIS article, and needless to say poisoning your body with alcohol is a fast track to limp, lifeless skin. Coffee is the worst culprit of the caffeine crew- explained in article link mentioned above. The article also has alternatives, ranging from less caffeinated matcha tea, to completely un-caffeinated dandelion teas, different adaptogens, and even naturally energizing beetroot kvass for a pre-workout.

  5. Toxic makeup and skin/ beauty products. This is a serious problem, because although you might think you're not using much, or that it's not being ingested: toxic makeup and body/ skin care is a chronic low level stressor that is truly poisoning you little by little. Ranging from artificial dyes, synthetic fragrances, harsh chemicals, and even formaldehyde- make the commitment to invest in your health and in the future of your glow by going 100% natural. And don't be fooled by greenwashing companies that slap the word "natural" or "hypoallergenic" on an otherwise toxicAF product... do your due diligence and ensure the products you use on your skin (that absorb directly into your bloodstream!) are safe. My skincare 101 article (HERE), and a look into my bathroom cabinet (HERE) both highlight some of my favourite and absolutely trust worthy products.


Collagen boosters

Gua Sha is the ancient art of lymph massage; it is known as an oriental facelift! Click image to learn more.

Gua Sha is the ancient art of lymph massage; it is known as an oriental facelift! Click image to learn more.

A herbal infusion is a great way to hydrate and infuse your water with an extra dose of vitamins, and minerals. Click image for instructions on how to make one.

A herbal infusion is a great way to hydrate and infuse your water with an extra dose of vitamins, and minerals. Click image for instructions on how to make one.

  1. Facial Massage: is a great way to boost natural collagen production. Gua Sha is my favourite way- learn how (and more on why) HERE.

  2. Topical collagen: products can be applied directly to the skin, but since the collagen particle is too big to penetrate the skin- it just sits on the surface. Not ideal. When it comes to topical stuff, your better option (IMO) is to nourish the skin with serums and oils, and boost blood flow (and collagen production) with facial massage; learn more about skincare HERE.

  3. Hydrate: Dehydrated skin is dull and sags, our cells need water to survive, let alone thrive. Hydrate with water that hasn't been chemically treated (aka tap water), because chemicals like chlorine destroy your guts micro biome and are not conducive to a thriving body. Opt for spring water or invest in a proper filter. Consider supercharging your water with collagen-boosting vitamin C (lemon juice!), gut healing apple cider vinegar, make a herbal infusion (learn how HERE), or add in a scoop of collagen beauty boosters.

  4. Nourish: Certain vitamins and minerals are precursors to collagen, and help boost the body's endogenous (self) production but also increase the bioavailability of a collagen supplement. These include: vitamin C (black currants, red peppers, kiwis, guava, strawberries, oranges, broccoli, parsley), manganese (mussels, sweet potato, pine nuts), copper (grass-fed beef liver, cacao, cashews, sunflower seeds), proline (bone broth, organ meats, grass-fed beef, wild caught fish, egg yolk from pasture raised chickens), glycine (bone broth, grass-fed beef, organ meats, egg yolk, spinach, kale, cauliflower and pumpkin), and foods high in anthocyanidins (blueberries, cherries, blackberries, red onion, purple cabbage, eggplant). It is highly recommended to consume your collagen powder with at least a source of vitamin C to help increase its absorption. Bone broth is another incredible way to nourish your body with the collagen (& gelatin) extracted from animal bones through the process of a low simmer. These gelatinous broths are full of minerals and vitamins as well.

  5. Supplement: is one of the most popular modern ways to get collagen, and has definitely been one of my most longstanding permanent relationships with a supplement. Collagen supplements vary, but



Bovine Collagen Peptides (Hydrolyzed)

Are the most common, and the most widely beneficial for the average human. The hydrolyzed process renders these collagen proteins extremely bioavailable, and the bovine source offers 20g of protein per scoop (contains 18 amino-acids, including 8 out of 9 essential amino-acids.). These collagen peptides are mostly type 1 and 3 collagens (which comprise 90% of our own bodies collagen makeup). Great for gut, hair, skin, nails and joints, ligaments, and tendons.


Marine Collagen Peptides (Hydrolyzed)

Like the bovine collagen peptides, this wild caught marine collagen supplement is flavourless, and dissolves in hot or cold water. Abundant in type 1 collagen, marine peptides are said to be the most bioavailable. Great for gut, hair, skin, nails and joints, ligaments, and tendons.


Cartilage Collagen

These capsules are made of type 2 collagen, ideal for building/ repairing cartilage, ligaments, tendons, skin, and bone. Made of bovine tracheal cartilage, they are great for super active people who pound the joints, or anyone with arthritis.

The beauty collagens come in many flavours, including melon mint (left) and lavender lemon (right). Unlike the aforementioned powders- these guys do have (natural, organic) flavour, as well as probiotics, hyaluronic acid, and of course collagen peptides. These beauty collagens are a great way to flavour your water, to help ensure you drink enough of it (and super boost you with goodness at the same time). 


What about cosmetic collagen?

Cosmetic collagen enhancers are simply a no. First of all, they are terrible for the body; collagen injections are not simply pure collagen- they contain synthetic compounds (including actual plastic) and come with a host of potential side effects including not only redness, itching, tenderness, rash, discolouration, lumps or asymmetry, and infection, but also all the long term impacts of essentially poisoning yourself (hello neurological damage- Alzheimer's, etc). Also, you look like a psycho (yes, people can tell you've botoxed the shit out of your face, no it does not look natural). Moreover, plastic surgery in general is just a dangerous slippery slope; learn to love your Self, support your body's natural process- and age with grace.


When? (collagen supplement timing)

Collagen supplement timing (kind of) depends on your goal.

Collagen peptides first thing in the morning can help balance blood sugar, reduce cravings and increase satiety throughout the day. Collagen peptides post-workout (along with a complete source of protein) will not only boost recovery speed, but also increase the absorption of the complete protein source. Collagen peptides before bed (on an empty stomach) will help heal the gut, reduce inflammation, and heal the body while you sleep and recover. 

I say timing "kind of" depends on your goal because the truth is, collagen protein at any time will essentially benefit all of the above. The benefits are less about timing, and more about consistency. Suggested use is 20 grams (one scoop) per day, every day. And this is not a hard feat considering how easy it is to incorporate into anything and everything you already eat. 

 I mix it into my drinks, smoothies, baked goods, sneak it into my chocolates, mix it in my coconut yogurt.. the possibilities are endless.

Some of my favourite recipes using collagen:

[click name for recipe]


Collagen chocolate almond butter cups

Cookie dough phat balls


Hot Choc


Adaptogenic cacao coyo bowl

Chocolate avocado pudding


Q- What difference might you see after taking a good collagen supplement for ages?

I have been drinking bone broth and taking a collagen supplement almost daily for years now- and first and foremost my intuition screams YES at this habit. I am very in tune with what my body needs and doesn’t, and there actually hasn’t been a single supplement that I’ve taken so long term without stopping. Whether it be chlorella, oregano oil, essential oils, ashwagandha, matcha, and even cacao- every so often my body just intuitively knows its time to take a break, and this hasn’t happened with collagen (or bone broth). I do consume bone broth warm (like a morning tonic) or cold (like as the base to a smoothie) depending on the weather, and simply incorporate collagen peptides powder in whatever I'm eating seasonally.


Anyways- benefits of taking a collagen powder supplement include:

This is the grass-fed, pasture raised bioavailable collagen protein powder that I take daily. Click image for more info.

This is the grass-fed, pasture raised bioavailable collagen protein powder that I take daily. Click image for more info.

- improves health and strength of skin and hair

- repairs joints

- heals cuts

- helps repair leaky gut

- boosts metabolism

- strengthens teeth and nails

- helps the body detoxify

- reduces cellulite/ stretch marks

- prevents and heals arthritis 

- speeds up repair of cuts

- hydrates the skin

- curbs cravings

- reduces inflammation

- calms nervous system

- improves sleep quality

- balances hormones


Although I have experienced many of these benefits over the years, it's essentially impossible for me to say (personally) that they are the sole cause of supplementing with collagen powder. My relationship with my body's health is preventative, not reactive. So I'm preventing problems by making healthy choices today- which makes it very hard to say specifically what caused health. Moreover, health is more than the sum of its parts; things work synergistically as a whole, and my lifestyle in general contributes to my overall wellbeing. My one personal anectdote is that I had a clicking knee from the time I was a youngin' up until I started taking collagen... clicking completely vanished! All I know is I feel good, and my intuition tells me collagen plays a vital role in this process. Collagen powder is now one of the very few supplements I actually travel with (I took it with me living off-the-grid in Maui for 3 months, and also backpacking through Europe for 2 months... #priorities). 


That being said, studies do show the very real impact of collagen, not only preventatively but more so reactively! Speeding up recovery, and reversing skin damage and wrinkled; including THIS double blind placebo study that showed a 20% reduction in wrinkles after just 8 weeks of taking a bioavailable form of collagen peptides. The study showed that supplement not only increased the collagen, but it actually boosted the body's ability to make its own!

Additionally, after 8 weeks of intake a statistically significantly higher content of procollagen type I (65%) and elastin (18%) in the BCP-treated volunteers compared to the placebo-treated patients was detected.
— Proksch et. al study, 2014

I've linked to nearly 20 other peer reviewed scientific studies at the bottom of this article, ranging from reduction of joint inflammation in athletes, to healing rheumatoid arthritis, to ealing the gut, reducing visible signs of aging (wrinkles) and more!


Q- Could you please explain the steps of bone broth making please?

Yes! There are so many variations, but I actually posted my favourite bone broth recipe (beef bone marrow) HERE. Alternatively you can use a chicken carcass for an insanely gelatinous broth (the cartilage super charges the type 2 collagen levels of your broth). Another way to benefit from the gelatinous goodness when simply roasting meat is to bake vegetables around your bone-in source of meat. Check out my baked chicken with collagen carrots recipe HERE.

Liquid gold. Click the image for my favourite bone broth recipe.

Liquid gold. Click the image for my favourite bone broth recipe.

Another way to get collagen is to oven roast your chicken surrounded with veggies. The gelatinous substance that comes out of the chicken as it cooks absorbs into the veggies and makes them delicious and crazy nutritious.

Another way to get collagen is to oven roast your chicken surrounded with veggies. The gelatinous substance that comes out of the chicken as it cooks absorbs into the veggies and makes them delicious and crazy nutritious.

I personally opt for homemade bone broth, once you get in the swing of it, it's so easy to make. If you're not into the idea, you can buy beef bone broth powder (like THIS one), or chicken bone broth powder (like THIS one). Whether you're making your own of buying a powder- it is imperative to get the highest quality because bones can be the source of incredible nutrition or poison, depending on how the animal lived his life. Animals store toxins in their bones, so pasture raised animals (grass-fed in the case of beef) and certified non-gmo is an absolute must.


Q- How can I get the best source of Collagen when beef proteins cause an allergic reaction? 

Marine Collagen, click image for more info.

Marine Collagen, click image for more info.

First of all, you should always primarily focus on nourishing your body with the collagen precursors (real, whole, vitamin and mineral rich foods). Opt for chicken bone broth (instead of beef), and as far as supplements: go with marine collagen! The marine collagen I use from Vital Proteins is made from the scales of fresh Non-GMO Project verified wild-caught snapper caught in Hawaii. It is highly bio-available, digestible, and soluble in cold and hot water. You can also get them in capsule form if the thought of fish powder ain't your thing (but truly, it blends seamlessly in hot or cold drinks, you won't even know it's there). 


Q- How much is too much? Does it suppress serotonin production? should everyone take it?

I don't actually believe there is a single supplement out there that everyone should take. We are such bio-individual beings, and at the end of the day only you can truly know what does and doesn't serve your highest good. When it comes to collagen peptides supplement, two red flags I know of are people with histamine issues, and of course allergies to the animal-product source in question. Bone broths and collagen peptide powders have been known to cause a histamine reaction in those sensitive to it; I have no solution for you there other than stay away from what makes you feel bad, work on nourishing and healing yourself with things that make you feel good and consider reintroducing it every so often as you get stronger to see how it goes.

There are many options when it comes to allergies (aforementioned) so whether it be chicken, bovine, marine, etc- opt for a supplement made with a product your body responds to well. 

Although collagen is extremely gut healing, it could cause problems if the leaky gut is really bad. Certain people with extremely destroyed gut walls have had problems with glutamine (an amino acid abundant in collagen); although glutamine is so so good for the gut, if your barrier is too porous it can actually let full particles through. Kind of how certain people need to heal their gut before consuming sauerkraut; although these things are good for the gut, your gut needs to be strong enough to properly break them down and utilize the nutrients. Catch 22.

And as for serotonin, there has been a study done using a gelatin-based protein to deplete tryptophan (a precursor to serotonin), which in turn affected serotonin levels. This is complicated, but a few notes: check in with yourself; if things don't make you feel good, don't take them! But it's not necessarily just the collagen, and perhaps more about an imbalance. Collagen and gelatin are full of amino acids: proline, glycine, glutamine and arginine, but they do not contain the amino acid tryptophan. So instead of not consuming collagen, you could supplement with tryptophan to balance it out; or even better: just eat meat!

I will elaborate on why in the question below.


Q- Is collagen a suitable replacement to my protein powder? 

Technically, no. Collagen is not a "complete protein", which means that it is not a replacement for “whole” protein. A whole protein means that the protein source contains all the nine "essential" amino acids that our bodies cannot synthesize (compared to the non-essential ones that we can synthesize). I used a bunch of quotation marks in there because I personally think the distinction between essential and non-essential amino acids is complete horse shit.

We love to isolate and categorize things as human beings, but as I've said before: things work synergistically with one another in ways we cannot completely fathom. The whole is more than the sum of its parts. And in this case- we see protein (say a lean cut of grass-fed, pasture raised steak), and able it "complete". But the reality is, it's actually lacking it's whole. The whole cow includes fat, cartilage, bones, and organs. When we eat the whole animal, we get all the amino acids, and together they are truly conducive to a healthy body. Glycine (one one the "non-essential") amino acids is actually depleted when we consume red meat- but this is only because we consume red meat in isolation from the whole cow- i.e. the glycine rich collagen! The studies that suggest that red meat reduces longevity fail to acknowledge many things, including the fact that when balanced out with non-essential aminos (the kinds we get either truly eating nose-to-tail, including bone broth), there is no bodily imbalance.

In one recent study, the relationship between red meat and diabetes was abolished after controlling for low-glycine status. People with low glycine levels and high meat intakes were more likely to have diabetes; people with higher glycine levels could have higher meat intakes without any issues. In another study, low circulating levels of glycine predicted diabetes risk. It may very well be that the way most people eat meat in developed countries—eating chicken breasts over chicken wings and skin, lean steak over oxtails and shanks, muscle meat over bones, skin, and tendons—is unhealthy. Increasing your collagen, then, could balance out the meat intake.
— Mark Sisson

See study HERE.

Organic, grass-fed, pasture raised whey protein- but make sure you balance out with collagen!

Organic, grass-fed, pasture raised whey protein- but make sure you balance out with collagen!

So although collagen is not a suitable replacement for "complete" proteins, it actually works wonders in conjunction with it. 

I personally don’t use protein powders because I try to get as much of my nutrition as possible from whole food sources, and so I consume plenty of high quality organic, pasture raised animal products. But whether you consume protein powders or animal meat: they be perfectly pared with a scoop of collagen peptides.


Q- Thoughts on vegan collagens? (Silicea colloidal gel)

So technically there is no such thing as a vegan collagen. Collagen by nature is an animal-based product (most commonly fish, chicken, bovine). If you are a vegan, you can supplement with collagen processors, as discussed briefly above under "nutrition". The body makes collagen naturally, so nourishing yourself with vitamins in minerals (particularly vitamin c, manganese, copper, proline), will help your body create its own.

Beef liver capsules and collagen powder are a great way to reintroduce animal products into your life if you are healing from veganism.

Beef liver capsules and collagen powder are a great way to reintroduce animal products into your life if you are healing from veganism.

The problem with this is that our bodies naturally slow down collagen production with age (starting around age 20!), so no matter how much you nourish- nothing really replaces the benefits of an actual collagen supplement in the diet. Now I'm not telling you to change your life in the name of collagen, but I will say that I personally know vegetarians and vegans that have used collagen powder as a "gateway" back into animal products. Knowing and trusting the brand quality (ethically that the animals were either pasture raised, or wild) has made this the perfect supplement for those not ready to actually consume straight up flesh. Another great gateway are grass-fed, pasture raised beef liver capsules (click HERE for more info). For more on how to recover from veganism, click HERE.


There are many vegan supplements that do support the body's creation of collagen (like silica, biotin), but these are not in fact collagen supplements. These vegan supplements can be a great way to give your body the necessary building blocks to make collagen, but as you age and the factory starts to slow down... nothing (IMO) beats just giving your body the ready-made product.


Q- what's the difference between collagen and gelatin powder?

Beef gelatin: for thickening liquids, making gummies, gravy, etc. Click image for more info.

Beef gelatin: for thickening liquids, making gummies, gravy, etc. Click image for more info.

Collagen and gelatin powders are derived from the same source- and so they have the same amino acid profiles and nutritional benefits; but they differ in the way they are processed, and they differ in the way they react as a substance. Gelatin is processed more gently- leaving long chain amino acids that dissolve in hot water but become gelatinous when chilled (think jell-o!). Gelatin is what's used to thicken soups, gravy, custards, gummies. Collagen is processed more aggressively which creates short chain collagen peptides, which dissolve in hot or cold liquid and are actually more bio-available (easy to digest and absorb). Both are highly anti-inflammatory, support healthy joints, bones, guts, hair, nails, skin, etc.


Q- Just tell me which one to buy.

Hahah, first of all let me say: don't ever just buy something because someone else advocates for it. You should always do your research, and know that just because something works for someone you respect or trust, doesn't mean it works for you.

That being said, if you're vibing collagen, I would choose one of the two below- depending on which you feel more drawn too. Both these collagen supplements are flavourless, will integrate in any hot or cold beverage, and are great high quality, properly sourced collagen.

(Click images for more info)

Like any supplement, it is so so important to trust the company you purchase from. Supplements can do a lot of damage otherwise, and collagen supplements are no exception. The Consumer Wellness Centre tested several collagen peptide brand and found alarming contents from powders not sourced from organic, pasture raised or wild animals (read more HERE). Your better off consuming less of a high quality supplement than any amount of a low quality one.


Any questions? Comment below!


May your skin be full, and your joint be supple!


Visit for more information on the products I mentioned above, you can also buy off of, and use code "DST929" for a discount on your entire order.

Dive Deeper


1. Why we need collagen by Mark Sisson -

2. What is collagen + it's benefits by Dr. Josh Axe-

3. Benefits of collagen by Wellness Mama - 

4. Collagen vs. gelatin

5. All about collagen and gelatin 

6. Consumer Wellness Report on tainted collagen peptides products



  1. Glycine

  2. L-proline

  3. Hydroxyproline

  4. L-alanine

  5. Vitamin C and collagen

  6. Collagen Precursors

  7. Collagen to reduce wrinkles in humans

  8. Collagen to reduce signs of ageing in humans

  9. Benefits of collagen studied in mice

  10. Study on gelatin-based protein and impact on tryptophan and serotonin

  11. Collagen anti-inflamatory

  12. Collagen promotes better sleep

  13. Improved sleep quality

  14. Collagen to reduce joint pain in athletes

  15. Collagen to strengten achilles tendon

  16. Impact of collagen on middle aged women

  17. Collagen speeds up healing of ulcers

  18. Collagen to treat rhumatoid arthritis