What Is Collagen?

Posted by Stars + Honey Team on

Key Points:

  • Collagen is an abundant structural protein that provides stability for connective tissue, skin, bones, and organs
  • There are at least 28 different collagen types, but types I-IV are the most well studied
  • Collagen is primarily made up of amino acids that act as building blocks for various body structures  like skin, hair, nails, joints, and organs. 
  • The body produces less collagen as people age—contributing to skin, joint, and muscle deterioration. 
  • Age-related decreases in collagen production makes collagen supplementation an attractive option for many.
  • Hydrolyzed collagen peptides are more easily absorbed than whole, native collagen particles found naturally in the wild.  

Why is Collagen Important?

Collagen is an abundant structural protein that plays a major role in the development, stability, repair, and rejuvenation of connective and organ tissue, bones, and skin. Due to its strength and abundance, collagen is also a key component of hair, nails, teeth, tendons, ligaments, muscles, and joints [1].

A collagen protein molecule comprises 18 amino acids and has particularly high levels of proline, hydroxyproline, and glycine [2]. The amino acids are linked together in chains that form collagen fibers. The collagen fibers twist together in a rope-like manner, and this formation provides structural support for cells, tissues, and organs throughout the body.

In addition to providing stability, collagen is a building block for another structural protein called elastin that allows tissues to be sturdy, but flexible. Furthermore, collagen formation helps heighten the release of hyaluronic acid from connective tissue cells [1, 3]. Healthy levels of collagen also afford antioxidant, lipid-balancing (fat-balancing), and blood pressure-normalizing properties [1].

Due to these properties, collagen has rapidly gained interest in the cosmetic, clinical, and nutraceutical industries. However, it is important to note that there are many different types of collagens that serve various functions.

Collagen Types

To date, 28 collagen types have been identified, but most research focuses on collagen types I-V [4]. The collagens of interest have been identified in the following parts of the body:

  • Collagen type I—the most common form found in the skin, bone, teeth, tendons, ligaments, vasculature, and organs. 
  • Collagen type II—present in cartilage.
  • Collagen type III—found in the skin, muscle tissue, and blood vessels. 
  • Collagen type IV—located in the organs and glands.
  • Collagen type V— main component of cell surfaces and the placenta.

Collagen types I through III are frequently used for cosmetic and clinical purposes due to their strong fiber-forming properties. Furthermore, collagen type I makes up about 90% of the collagen protein in the human body, followed by collagen type II [5, 6]. Additional collagen types are found in low levels in other parts of the body and in specific organs.

Age-Related Changes in Collagen Production

As you get older, your body begins to produce less collagen, and the levels gradually decrease by about 1% every year [7]. This occurs in both men and women. However, women who are going through menopause often experience a 2% decrease in collagen levels each year, while the rate of collagen loss remains at around 1% every year for older men [7]. 

As time passes, collagen fibers also become damaged—losing strength, firmness, and thickness through a degenerative process that is associated with the skin-aging phenomenon as well as other issues such as muscle or joint problems [1]. Low collagen levels are linked to thin hair, dry skin, wrinkles, brittle nails, and weak connective tissue, among other health issues [8, 9].

The gradual loss of collagen makes it optimal to supplement the diet with this key structural protein. Supplementation at any age can be beneficial, as collagen supports healthy hair, skin, nails, joint, and muscle structures. Regular supplementation has also  been found to combat many types of age related declines in collagen production [1, 8, 9].

Can You Get Enough Collagen From Food?

Although certain types of food such as beef, poultry, fish, soy, legumes, and dairy contain collagen, it is hard to consume adequate amounts unless collagen is taken in supplement form. 

Furthermore, native collagen in its pure, whole form is harder on the intestines due to its large size. This prevents digestive enzymes from properly breaking down native collagen into amino acids that can be transferred through the bloodstream to different tissues and organs, where the amino acids are converted into key proteins that carry out vital processes. When native collagen is consumed instead of hydrolyzed collagen peptides, only a small amount reaches the bloodstream and the rest is simply excreted as waste.

Research shows that taking an adequate amount of collagen peptides—also known as hydrolyzed collagen or collagen hydrolysate—promotes noticeable benefits in many humans in about 4 to 12 weeks, depending on the amount taken [10, 11]. Collagen peptides consist of short chains of amino acids. This form of collagen is much easier to absorb, digest, and utilize than whole, native collagen. 

Stars + Honey Collagen Protein Bars contain 10 grams of hydrolyzed collagen peptides from bovine sources that contain both types I and III collagen. We designed them to be convenient, delicious and easy to digest so you could stick with your collagen supplement routine – and even look forward to it. 


  1. Rodriguez MIA, Barroso LGR, Sanchez ML. Collagen: A review on its sources and potential cosmetic applications. J Cosmet Dermatol. 2018;17(1):20-26.
  2. Ottani V, Martini D, Franchi M, et al. Hierarchical structures in fibrillar collagens. Micron. 2002;33:587-596.
  3. Sibilla S, Godfrey M, Brewer S, et al. An overview of the beneficial effects of hydrolysed collagen as a neutraceutical on skin properties: Scientific background and clinical studies. Open Neutraceutical J. 2015;8:29-42.
  4. Gelse K, Poschl E, Aigner T. Collagens – Structure, function, and biosynthesis. Adv Drug Deliv Rev. 2003;55:1531-1546.
  5. Leon-Lopez A, Morales-Penzloza A, Martinez-Juarez VM, et al. Hydrolyzed-collagen—Sources and applications. Molecules. 2019;24(22):4031-4047.
  6. Naomi R, Ridzuan PM, Bahari H. Current insights into collagen type I. Polymers (Basel). 2021; 13(16): 2642-2661.
  7. Brincat M, Versi E, Moniz CF, et al. Skin collagen changes in postmenopausal women receiving different regimens of estrogen therapy. Obstet Gynecol. 1987;70(1):123-127.
  8. Asserin J, Lati E, Shioya T, Prawitt J. The effect of oral collagen peptide supplementation on skin moisture and the dermal collagen network: evidence from an ex vivo model and randomized, placebo-controlled clinical trials. J Cosmet Dermatol. 2015;14(4):291-301. 
  9. de Moraes LO, Lodi FR, Gomes TS, et al. Immunohistochemical expression of types I and III collagen antibodies in the temporomandibular joint disc of human foetuses. Eur J Histochem. 2011;55(3):e24.
  10. Khatri M, Naughton RJ, Clifford T, et al. The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: A systematic review. Amino Acids. 2021;53:1493-1506.
  11. Abrahams M, O'Grady R, Prawitt J. Effect of a daily collagen peptide supplement on digestive symptoms in healthy women: 2-Phase mixed methods study. JMIR Form Res. 2022;6(5):e36339

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