The Science of Collagen

April 15th, 2022

Collagen sales have exploded over the past decade, and according to Global Market Insights, the collagen industry is expected to hit a whopping 6 billion dollars in revenue by 2026. Based on the growth projection, I think it’s safe that collagen interest is here to stay.

As nutrition professionals, we’re a reliable voice in a dubious market, and to meet the demand of consumer interest, we need to understand the science behind the expanding trend. So what exactly is collagen, why is it important, and is it the answer to good joints, strong nails, and flawless skin? Let’s dive in.


What is collagen?

Collagen is the main structural protein found throughout the body, representing approximately 30% of total protein mass. (1) Interestingly, the word “collagen” comes from the Greek word “kolla,” which translates to “glue producer.” (2) It forms all connective tissues, including the skin, nails, tendons, and ligaments, and is the most abundant fibrous protein within the extracellular matrix (ECM) (1).


Structure and types of collagen

Collagens consist of three polypeptide chains arranged to form a triple helix. Each chain consists of 1050 amino acids, primarily glycine, proline, and hydroxyproline. (3) To date, 28 different types of collagen have been identified, each labeled with a Roman numeral. (4) The five most common types include:

Type I: the most predominant collagen type throughout the body, making up 90% of total collagen. Commonly found in the skin, bones, capsules of organs, tendons, cornea, and fascia. (5)

Type II: mainly found in cartilage, vitreous body (eyes), and nucleus pulposus (vertebrae discs) (6)

Type III: the second most abundant collagen throughout the body, found in skin and fibers of the lungs, spleen, liver, and lymphatic system. (2)

Type IV: forms the basal lamina and basement membrane. (7)

Type V: found in the placenta, corneas, hair, and bones. (7)

Collagen has many noteworthy characteristics, including its excellent durability and strength exhibited by its presence in tendons and bones. It supports skin elasticity and protects against the absorption of toxins and pathogens through the skin. Collagen also plays a significant role in cellular health, tissue and organ development, and bone and blood vessel healing. (3)


What impacts collagen levels in the body?

Several factors impact collagen production in the body, including

  • Age
  • Genetics – (i.e. COL14A1, COL5A1, COL4A2, COL3A1, COL1A1, and COL18A1) (18)
  • Smoking
  • Stress
  • Nutrient deficiencies and poor diet quality (e.g., low vitamin C, high refined sugar intake)
  • Excess sun exposure
  • Osteoporosis
  • Heritable/genetic conditions (e.g., Ehlers-Danlos syndrome, Osteogenesis Imperfecta, Stickler Syndrome, Alport Syndrome, Marfan Syndrome, Epidermolysis Bullosa)
  • Autoimmune conditions (e.g., Systemic Lupus Erythematosus, Systemic Sclerosis, Oral submucous fibrosis, Sjogren’s syndrome, Scleroderma, Rheumatoid Arthritis, Ankylosing Spondylitis) (2)


What are the benefits of collagen?

Collagen possesses many health benefits, including anti-inflammatory and antioxidant capabilities. According to an article in the Journal of Scientific and Technical Research, collagen hydrolysate can increase the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). (8)

Data also suggests that collagen can impact skin, nails, bone and joint health, and people with type 2 diabetes.


Collagen is a significant component of skin, with type I constituting 70% of skin collagen. (2) It helps maintain skin elasticity and hydration and decreases the formation of deep wrinkles.

Skin aging is a complex biological process that involves the degradation of collagen by intrinsic and extrinsic forces, including UV radiation, reactive oxygen species (ROS), and the production of advanced glycated end products (AGEs). Smoking, stress hormones, and a disrupted circadian rhythm also impact collagen synthesis and skin health. (7)

Several studies have shown a positive impact of collagen supplementation on skin health and integrity. One study, in particular, reviewed 11 randomized-controlled trials using collagen supplements for anti-aging benefits. Skin elasticity and hydration improved after 3 grams of collagen ingestion per day for 4-12 weeks. (7)

A 2014 double-blind, placebo-controlled study found that 2.5g of bioactive collagen peptides (BCP) significantly reduced eye wrinkle volume after eight weeks compared to the placebo group. The same study found that after eight weeks, the BCP group saw a 65% increase in procollagen type I collagen and an 18% increase in elastin (another important skin component). (9)


Brittle nails can be a symptom of various deficiencies like low protein, iron, zinc, and omegas-3s. Interestingly, collagen supplementation might be an effective treatment strategy for strengthening nail integrity. A 2017 study found that 2.5 grams of BCP intake for 24 weeks increased nail growth by 12% and decreased broken nail frequency by 42%. An impressive 88% of study participants noted an improvement in nail health after four weeks of BCP treatment. (10)

Bone and joint health

Collagen production declines with age, thus impacting cartilage, tendons, and ligaments—consequently, degenerative joint disorders and osteoarthritis risk increase. However, research shows that various collagen supplements can also help reduce joint pain in healthy individuals. In fact, a 2016 systematic review found that 10 grams of collagen hydrolysate per day for 24 weeks reduced joint pain and inflammation in 147 healthy athletes. (11, 12)

Collagen supplementation has also been found to improve pain in people with rheumatoid arthritis. An interesting study in Arthritis Care & Research assessed the use of chicken-derived type II collagen in rheumatoid arthritis versus methotrexate. Both study groups revealed statistically significant improvements in joint pain, swelling, and stiffness. The collagen group reported fewer adverse side effects than the methotrexate treatment group. (13)

Type II Diabetes

Studies show that marine-derived collagen peptides might be beneficial for people with type 2 diabetes. A randomized, placebo-controlled study on 100 participants with type 2 diabetes assessed the effect of 6.5 grams of marine-derived collagen taken daily with breakfast and before bedtime. Results showed a reduction in fasting glucose, hemoglobin A1c, blood insulin, LDL-C, total triglycerides, CRP, and free fatty acids after 3 months. An increase in HDL-C and insulin sensitivity index was also demonstrated. (14)


Chicken collagen hydrolysate (CCH) has been shown to have anti-hypertensive effects. A placebo-controlled, double-blind study found that 2.9 grams of CCH per day for 12 weeks reduced systolic and diastolic blood pressure, increased serum nitric oxide, and improved vascular protection in people with mild hypertension or high-normal blood pressure. (15)


Collagen Supplements

Collagen supplements can come from many different animal sources, including bovine, porcine, and marine.


Bovine collagen is extracted from cow skin and bones and is one of the major industrial sources of collagen. A disadvantage of bovine collagen is two-fold: a) there’s a risk of zoonosis and other contaminants, and b) 3% of the population is allergic to it. (3)


Porcine collagen is extracted from the skin and bones of pigs. It does not cause an allergic response like bovine collagen, but zoonosis poses a potential risk. (3)


Marine-derived collagen is the safest collagen available for many reasons:

  • free of zoonosis like mad cow disease
  • high collagen concentration
  • environmentally friendly
  • better absorption rate due to lower molecular weight
  • low inflammatory and allergen response
  • low risk of biological contaminants and toxins (3)

During processing, collagen is extracted from the skin, bones, cartilage, and tendons using hot water. This process forms gelatin, aka “partially hydrolyzed collagen.” Gelatin is then broken down via enzymatic hydrolysis to form collagen hydrolysate (CH). Collagen hydrolysate is commonly found in collagen supplements because it’s easily absorbed and has a higher bioavailability than gelatin. (8)


What to consider when recommending collagen supplements:

  1. Consider food allergies and intolerances (including histamine intolerance). Marine-based collagen sources are the least allergenic but are not suitable for people with a fish allergy.
  2. Be mindful of religious and cultural preferences and collagen sourcing.
  3. Ensure the product is third-party tested. Check and for more information.
  4. For marine-derived collagen, look for Marine Stewardship Council (MSC) certification. For bovine-derived collagen, look for grass-fed and/or pasture-raised.
  5. Check for a certificate of analysis (COA).
  6. Choose the correct collagen type based on the desired outcome. Type I and type III collagen are mainly used for skin health and anti-aging effects. Type II collagen is generally used for joint pain and in people with osteoarthritis.


Supplement dosing

Collagen supplements include the manufacturer’s daily dosing recommendation. A dosing range from 2.5-15 grams per day is generally safe and effective.

Condition Dosing Outcome
Skin 2.5g porcine-derived type I collagen (VERISOL) for 8-weeks ↑ procollagen type I

↑ elastin

↓ eye wrinkle volume

Nails 2.5g porcine-derived type I collagen (VERISOL) for 24-weeks ↑ nail growth by 12%
↓ broken nails by 42%
Bone and Joint 10g collagen hydrolysate for 24-weeks ↓ joint pain when walking, standing, and running
Rheumatoid Arthritis 0.1mg/day chicken-derived type II collagen for 24-weeks ↓ pain and tenderness

↓ stiffness

↓ swollen joints

Type II Diabetes 6.5g marine-derived collagen for 3 months ↓ fasting glucose

↓ fasting insulin

↓ A1c


↓ triglycerides


↓ free fatty acids

Hypertension 2.9g chicken collagen hydrolysate for 3 months ↓ systolic blood pressure

↓ diastolic blood pressure

↑ serum nitric oxide



Diet recommendations for collagen support

Most importantly, we can support intrinsic collagen production via collagen-promoting nutrients. The following nutrients are beneficial for collagen production:

Glycine Bone broth, poultry skin, seafood, meat, dairy products, spinach, peanuts, seaweed, cabbage, asparagus, watercress
Proline Meat, fish, liver, cabbage, soy, beans, peanuts, egg yolks
Hydroxyproline Meal, offal, organ meats, fish, bone broth, alfalfa sprouts
Copper Liver, oysters, mushrooms, nuts, seeds, leafy greens, dark chocolate
Zinc Meat, fish, oysters, legumes, dairy
Vitamin C Oranges, mangos, grapefruits, kiwis, strawberries, peppers, tomatoes
Sulfur/sulforaphane Raw broccoli, cabbage, cauliflower, watercress, Bok choy, mustard
Other antioxidant-rich foods Berries, beets, artichokes, oregano, rosemary, cinnamon, turmeric


Other lifestyle recommendations

  1. Avoid refined sugar. To no surprise, a diet high in refined sugar can negatively affect collagen production. Refined sugar can increase advanced glycated end products (AGEs) in the body, which can degrade the production of collagen and elastin in the skin. (16)
  2. Cook at a lower temperature like boiling, steaming, and sous vide. High-temperature cooking (e.g. grilling, roasting, air-frying, and frying) can also lead to the formation of AGEs and accelerate collagen degradation.
  3. Limit/avoid alcohol. Overconsuming alcohol can lead to reactive oxygen species and oxidative stress, both of which are detrimental to collagen synthesis. (17)
  4. Encourage effective stress-management strategies. Try utilizing the 5R strategy, as mentioned in the IFNA training:
  • Is there something in your life that you want to REMOVE? 
  • What would you REPLACE it with? 
  • How would you REPOPULATE your current life with joy, purpose, and meaningful social connections?
  • Is there a relationship that you want to REPAIR?
  • What could you do now to REBALANCE your work and your life?



While collagen might be trendy amongst influencers, it’s safe to say that we do have science to support its use for specific conditions and ailments. Fortunately, collagen supplementation is safe with minimal adverse effects, but it’s important to be aware of food sensitivities/allergies. And before lathering in collagen for wrinkle support, consider the brand, quality (i.e. wild-caught for marine, pasture-raised for bovine), collagen type, and collagen source (i.e., bovine, porcine, or marine-based).

To learn more about various supplements, like collagen, be sure to sign up for IFNA Track 1. Kelly Morrow, MS, RDN, FAND goes into great detail about how to assess various supplements for quality assurance.

by Tori Eaton, RDN, LDN, IFNCP


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