Avian cartilage

Other Names

avian collagen type IIavian sternal cartilagechicken breast cartilagechicken cartilagechicken collagen peptidechicken collagen type IIchicken keel cartilagechicken sternal cartilagechicken sternum cartilagecollagen from chicken sternal cartilagecollagen type II (avian)desiccated avian sternal cartilagehydrolysate of avian cartilagehydrolyzed chicken cartilagehydrolyzed collagen type II (avian)native type II collagen (chicken sternum)poultry cartilageundenatured type II collagen (avian source)

Synopsis

Avian Cartilage

1. Identity, Source, and Common Forms

1.1 Nomenclature and Chemical Identity

Avian cartilage is the hyaline cartilage tissue harvested from domesticated birds—almost exclusively the domestic chicken (Gallus gallus domesticus)—and used as a dietary supplement or functional food ingredient. The material is most commonly obtained from the sternal (keel) cartilage, the cartilaginous extension of the breastbone, because it yields a high concentration of the tissue's most commercially important macromolecules. Type II collagen (Col II) and chondroitin sulfate (CS) are the main macromolecules in the extracellular matrix, and their characteristics have been studied extensively in chicken sternal cartilage (CSC) as a primary extraction source.

In the dietary supplement trade, avian cartilage appears under several proprietary and generic designations. Undenatured (or native) type II collagen, often sold under the registered brand name UC-II®, refers to collagen that has not been thermally or chemically denatured and retains its native triple-helical structure. An emerging novel nutraceutical ingredient known as UC-II has received considerable attention in the treatment of osteoarthritis; UC-II is a novel undenatured type II collagen derived from chicken sternum cartilage. A separate, hydrolyzed preparation marketed as BioCell Collagen® (BCC) contains a low-molecular-weight matrix of hydrolyzed collagen type II together with chondroitin sulfate and hyaluronic acid. BioCell Collagen® contains a naturally occurring matrix of hydrolyzed collagen type II and low-molecular-weight hyaluronic acid and chondroitin sulfate. Early desiccated preparations are represented by the trademarked powder Kolla2™, described in patents as extracted from desiccated avian sternal cartilage collagen type II powder. This composition is extracted from desiccated avian sternal cartilage collagen type II powder, with use for arthritis as a therapeutic agent and nutritional food supplement.

Chicken type II collagen is additionally described in the scientific literature as CCII (chicken type II collagen) when distinguishing it from bovine-derived sources. Chicken type II collagen (CCII) is a protein extracted from the cartilage of chicken breast and exhibits intriguing possibilities for the treatment of autoimmune diseases by inducing oral tolerance.

1.2 Natural Source and Anatomical Origin

The chicken sternum is the primary commercial source. The chicken sternum is a promising source of collagen and CS. The choice of sternal rather than bone-adjacent tissue is deliberate: maintaining pure cartilage tissue is critical to product purity because it avoids contamination of collagen type II with types I and III found in bone. The fresh sternal cartilage is promptly frozen after harvest, and it is exclusively the sternal cartilage that is used for preparing collagen type II powder. Chicken feet and other poultry-derived connective tissues also contain type II collagen and are consumed in numerous traditional cuisines, but the sternal cartilage is the standard raw material in the supplement industry due to its concentrated collagen and glycosaminoglycan content. By utilizing the sternum—a significant by-product of chicken production—research on this source aims to contribute to the productive use of poultry waste.

1.3 Common Forms and Preparations

Avian cartilage is processed into dietary supplement form in several distinct ways, each yielding a product with different structural and bioactive characteristics:

Undenatured (native) powder / UC-II®: The investigational UC-II product is derived from chicken sternum and manufactured using a patented, low-temperature process to preserve its native structure. This approach retains the intact triple-helical collagen conformation believed necessary for immune modulation (see Section 4).
Hydrolyzed extract (BioCell Collagen®): Produced by enzymatic hydrolysis of chicken sternal cartilage to yield collagen type II fragments of low molecular weight together with depolymerized chondroitin sulfate and hyaluronic acid. A patented method involves treating fresh chicken sternal cartilage with a proteolytic enzyme to form a hydrolysate having at least 20% depolymerized chondroitin sulfate and at least 10% hyaluronic acid, with hydrolyzed collagen type II fragments having an average molecular weight of approximately 5,500 to 10,000 daltons.
Desiccated whole-cartilage powder (Kolla2™): Prepared by freeze-drying or low-temperature desiccation of the raw sternal cartilage material with minimal processing. For oral administration as a nutritional dietary supplement, this powder may be provided as a dispersible powder or granule, tablet, hard or soft capsule, emulsion, aqueous or oil suspension, syrup or elixir.
Isolated constituents (purified CS or type II collagen): Extracted using enzymatic hydrolysis under varying conditions. For Col II and CS obtained from chicken sternal cartilage, the highest efficiency of enzymatic hydrolysis was achieved after 24 and 6 hours of treatment respectively, yielding average molecular weights of 130 kDa (α1 chain) and 270 kDa (β chain) for Col II, and 80.27 kDa for CS.

2. Traditional and Historical Use

2.1 Traditional Chinese Medicine and Asian Culinary Traditions

The use of cartilage-containing bird preparations as food-medicine has deep roots in East Asian traditions. Chicken bone broth has been consumed for centuries in Traditional Chinese Medicine (TCM) as a healing food believed to improve health and longevity. More than 2,500 years ago in Chinese medicine, bone broth was used to strengthen the kidneys and support digestive health, and it subsequently became a staple of traditional Asian meals, frequently used as the base for Chinese, Korean, and Japanese soups.

Within TCM dietary therapy, the preparation emphasizes extended, slow simmering of bones and connective tissues. To extract as much of the nutrients as possible, the broth is typically cooked over 24–48 hours; the slow cooking process extracts minerals, collagen, amino acids, and other supportive nutrients from the bones and connective tissues. The resulting gel-like broth is regarded in TCM frameworks as warm, nourishing, and tonifying. Bone broth is seen as warm, nourishing, and tonifying—excellent for patients who are weak, tired, and convalescing—and can be particularly beneficial for those with weakened digestive systems.

Chicken feet—which are rich in type II collagen—are a widely consumed food in many parts of the world. Eating collagen-rich chicken feet is common in many countries, including China, Indonesia, Korea, Thailand, Laos, Malaysia, Trinidad and Tobago, Ukraine, Russia, Romania, Moldova, Jamaica, South Africa, Peru, Mexico, the Philippines, Cambodia, and Vietnam. In TCM practitioner contexts, chicken bone broth is specifically applied to support kidney function, digestive health, and blood building. Chinese medicine practitioners use chicken bone broth to strengthen the kidney, support digestive systems, and build blood.

In cultures across Europe, Asia, and Africa, the slow cooking of bones has for millennia produced inexpensive but nutritious meals. What began as a way for poorer households to extract value from scraps became a long-standing tradition; through extended simmering, bones release collagen, gelatin, and minerals such as calcium, magnesium, and phosphorus, along with amino acids—substances believed to support joint function, bone strength, digestion, and recovery.

2.2 European and Western Traditions

In Western culinary traditions, chicken soup prepared from boiling chicken bones and connective tissue has long been used as a folk remedy, particularly for respiratory illness. In Traditional Chinese Medicine, bone broths still play a restorative role, while in African contexts they remain valued for the sick and for women after childbirth; European traditions likewise placed meat and bone broths at the heart of household healing and strengthening remedies. The informationally rich amino acid glycine present in chicken broth, alongside its mucolytic constituent cysteine, are now thought to partially explain such traditional applications. Biochemically, chicken broth is uniquely rich in soluble cysteine, glycine, and proline; cysteine in particular acts as a mucolytic, directly reducing mucus viscosity.

The specific isolation and concentration of avian cartilage as a supplement—distinct from whole-food broth consumption—is a modern development that emerged in the late twentieth century, driven initially by research into type II collagen oral tolerance in the context of rheumatoid arthritis and, subsequently, by interest in osteoarthritis management and cosmetic skin-aging applications. Most structural molecules in joint supplement formulations had been extracted from cattle cartilage for many years; however, since the appearance of bovine spongiform encephalopathy (BSE), the food, pharmaceutical, and cosmetic industries became concerned about possible contamination of these extracts by BSE-responsible prions, which are not inactivated by heat and are difficult to detect. The BSE crisis from the 1990s onward drove significant commercial and scientific interest toward avian-derived collagen as a safer alternative source.

3. Key Constituents and Active Compounds

3.1 Type II Collagen

Type II collagen (Col II) is the dominant structural protein of hyaline cartilage and the primary active constituent of avian cartilage preparations. Type II collagen (Col II) and chondroitin sulfate (CS) are the main macromolecules in the extracellular matrix. Fourier transform infrared spectroscopy has revealed that Col II samples from chicken sternal cartilage maintain their triple-helical structure and that the predominant type of chondroitin sulfate is chondroitin-4-sulfate. The triple-helical conformation is considered critical for the supplement's immunological mechanism of action: preservation of this native structure, achieved through low-temperature processing, is specifically what distinguishes the "undenatured" preparation (UC-II®) from hydrolyzed forms. Collagen type II contains the greatest concentration of proteoglycans, which help rejuvenate connective tissue joints.

The amino acid profile of avian sternal cartilage collagen differs from that of typical collagen preparations. The unique amino acid composition and molecular weight of the powder differs substantially from typical collagen proteins; tryptophan and hydroxylysine amino acids are absent and hydroxyproline is low.

3.2 Chondroitin Sulfate

Glycosaminoglycans (GAGs) can be categorized into sulfated GAGs—which include chondroitin sulfate (CS), dermatan sulfate, keratan sulfate, and heparin/heparan sulfate—and nonsulfated GAGs such as hyaluronic acid. CS consists of N-acetylgalactosamine and glucuronic acid; it is widely found on cell surfaces and within extracellular matrices, and is a cartilage protective agent commonly used for osteoarthritis treatment. CS is primarily sourced from diverse by-products derived from land and sea animals, including cartilage, bovine trachea, fish bone and fins, and chicken keel cartilage.

3.3 Hyaluronic Acid

Avian sternal cartilage is also a natural source of hyaluronic acid (HA). Hydrolyzed preparations such as BioCell Collagen® contain low-molecular-weight HA as an intrinsic matrix component. After enzymatic hydrolysis of chicken sternal cartilage, the hydrolysate contains at least 10% hyaluronic acid alongside depolymerized chondroitin sulfate and hydrolyzed type II collagen. HA is a non-sulfated glycosaminoglycan that plays fundamental roles in joint lubrication and water retention within connective tissues. Glycosaminoglycans exhibit significant functions in a range of physiological processes, such as the regulation of electrolytes and management of water retention.

3.4 Natural Lipids

Desiccated avian cartilage preparations also retain natural lipids present in native cartilage tissue. The natural lipids found together with collagen II protein and carbohydrates constitute the chief structural components of joint cartilage cells; the molecular weight, amino acid composition, and natural lipids are considered essential to promote optimal assimilation of the peptides.

4. Mechanisms of Action

4.1 Oral Tolerance (Undenatured Type II Collagen)

The primary proposed mechanism for the undenatured form of avian type II collagen is oral tolerance—an immune process operative in gut-associated lymphoid tissue. UC-II has a definite immune-mediated mechanism of action named oral tolerance. Oral tolerance is an immune process where the body differentiates between harmless antigens such as dietary proteins or commensal microorganisms and potentially detrimental foreign aggressors; it initiates in the gut-associated lymphoid tissue (GALT).

UC-II acts via a specific immune-mediated mechanism known as oral tolerance, which can lead to reduced inflammation and enhanced cartilage repair in the knee joint. More specifically, native type II collagen derived from chicken sternal cartilage possibly acts by desensitizing the T-cell-mediated attack on native type II collagen and can thus help prevent joint inflammation and degradation. At the cellular level, oral administration of type II collagen is associated with generation of immunoregulatory T-cell populations. Mice tolerized by repeated oral feeding of CII before collagen-induced arthritis induction showed significantly less joint inflammation; mice fed CII also exhibited increased serum IgG1 and decreased serum IgG2a compared with non-tolerized arthritic animals.

Downregulation of the immune response to CII may help prevent destructive arthritis; oral administration of CII is an established procedure for inducing peripheral immune tolerance, which suppresses autoimmune responses in RA. The precise cellular mechanisms of oral tolerance to CII are not fully characterized. Bovine or chicken CII has been administered orally to RA patients, resulting in some clinical improvement; however, the precise mechanisms of oral tolerance are not fully known.

UC-II acts via a definite immune-mediated mechanism named oral tolerance, which ultimately leads to secretion of anti-inflammatory cytokines and simultaneous decrease in expression of pro-inflammatory cytokines, essential to reduce inflammation and enhance cartilage repair in the joint.

4.2 Anti-Inflammatory Effects of Chondroitin Sulfate and Collagen Peptides

In preclinical models, the bioactive compounds of chicken cartilage exert anti-inflammatory effects through distinct molecular pathways. In rat models, oral chondroitin sulfate, cartilage powder, and type II collagen peptides could increase the athletic ability of rats and reduce inflammatory cytokine levels in serum or synovial fluid, including prostaglandin E2, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-17. The morphological structure of articular cartilage indicated that CS could significantly improve cartilage tissue morphology and reduce OA score; oral CS slowed down the development of OA by modulating gut microbiota.

4.3 Structural Support (Hydrolyzed Preparations)

Hydrolyzed collagen preparations are postulated to provide substrate for cartilage and skin matrix synthesis. The low-molecular-weight peptide fragments resulting from enzymatic hydrolysis are considered more bioavailable for intestinal absorption. Such processed forms of collagen type II are considered less effective in absorbing into the gastrointestinal tract compared to the native sternal cartilage preparation, a claim made in the context of comparing processing approaches. In skin tissue, hydrolyzed preparations from avian cartilage may support the accumulation of dermal collagen: dietary supplementation of chicken sternal cartilage extract supports the accumulation of types I/III collagen in skin to promote increased elasticity and reduced skin wrinkling in women aged 39 to 59.

5. Scientific Evidence by Area of Application

5.1 Osteoarthritis (OA)

5.1.1 Undenatured Type II Collagen (UC-II®)

The clinical evidence base for UC-II® in osteoarthritis is the most developed among avian cartilage preparations. A 2009 clinical trial by Crowley et al., published in International Journal of Medical Sciences, compared UC-II to a combination of glucosamine and chondroitin (G+C) in subjects with knee OA. The trial evaluated the safety and efficacy of UC-II as compared to a combination of glucosamine and chondroitin (G+C) in the treatment of OA of the knee; the results indicate that UC-II treatment was more efficacious, resulting in significant reduction in all assessments from the baseline at 90 days, whereas this effect was not observed in the G+C treatment group. Specifically, treatment with UC-II reduced the WOMAC score by 33% as compared to 14% in the G+C treated group after 90 days, and UC-II treatment decreased VAS score by 40% after 90 days as compared to 15.4% in the G+C treated group. Treatment with UC-II reduced the Lequesne's functional index score by 20% as compared to 6% in the G+C treated group at the end of the 90-day treatment.

A larger multicenter, randomized, double-blind, placebo-controlled trial by Lugo, Saiyed, and Lane (2016), published in Nutrition Journal, enrolled 191 subjects with knee OA. Undenatured type II collagen (UC-II) is a nutritional supplement derived from chicken sternum cartilage; the study evaluated its efficacy and tolerability for knee OA pain and associated symptoms compared to placebo and to glucosamine hydrochloride plus chondroitin sulfate (GC); 191 volunteers were randomized into three groups receiving a daily dose of UC-II (40 mg), GC (1500 mg G and 1200 mg C), or placebo for a 180-day period. The UC-II treated group showed significant improvements in WOMAC subscales and total scores, VAS score, and LFI compared to placebo at 180 days follow-up; the UC-II group also showed significant improvements for WOMAC total score, pain and stiffness, VAS score, and LFI compared to GH+CS at 180 days follow-up; safety outcomes were similar for all three groups.

A subsequent multicenter, randomized, double-blind, placebo-controlled study (Schön et al., 2022, published in the Journal of Integrative and Complementary Medicine) assessed UC-II's effect on knee joint flexibility in 96 healthy subjects with activity-related joint discomfort (ArJD) but without diagnosed OA. The study was conducted in healthy subjects with ArJD who had no history of osteoarthritis or joint diseases; 96 subjects (aged 20–55 years) who reported joint discomfort while performing a standardized single-leg-step-down test were randomized to receive either placebo (n=48) or 40 mg of undenatured collagen (n=48) supplementation daily for 24 weeks.

A 2025 systematic review and limited meta-analysis (published in Annals of Medicine, accessible via PMC) examined 12 studies—3 pre-clinical, 8 clinical, and 1 combining both—meeting predefined inclusion criteria. The review concluded that UC-II acts via oral tolerance and can lead to reduced inflammation and enhanced cartilage repair in the knee joint; in addition, administration of UC-II (40 mg daily) is safe and efficacious in the short- and mid-term, reducing inflammation and pain and improving function, range of motion, and overall quality of life. The same review noted a gap: as of August 13, 2024, there are no ongoing clinical trials registered on ClinicalTrials.gov, CTRI, or ChiCTR to study the safety and efficacy of UC-II alone for the management of knee OA.

Evidence strength (OA): Multiple small-to-moderate-sized randomized controlled trials report favorable outcomes for pain and function measures over 90–180 days. A systematic review supports short- to mid-term efficacy. Important limitations include: several pivotal studies were conducted by or in collaboration with the ingredient manufacturer (InterHealth Nutraceuticals), raising potential conflicts of interest; sample sizes are modest; long-term structural outcomes (cartilage preservation on imaging) have not been established in large independent trials.

5.1.2 Hydrolyzed Avian Cartilage Extract (BioCell Collagen®)

A randomized, double-blind, placebo-controlled trial (Schauss et al., 2012, Journal of Agricultural and Food Chemistry) examined BioCell Collagen in OA. The aim of this trial was to investigate the tolerability and efficacy of BioCell Collagen (BCC), a low-molecular-weight dietary supplement consisting of hydrolyzed chicken sternal cartilage extract, in the treatment of OA symptoms; patients (n=80) had physician-verified evidence of progressive OA in their hip and/or knee joint, with joint pain present for 3 months or longer and pain levels of 4 or higher at baseline. The RCT enrolling 80 subjects demonstrated that BioCell Collagen was well tolerated with no serious adverse events and led to a significant improvement in joint mobility compared to the placebo group on day 35 (p=0.007) and day 70 (p<0.001).

5.2 Rheumatoid Arthritis (RA)

Chicken type II collagen has been studied in RA, primarily through the oral tolerance mechanism. A landmark phase III clinical trial (Wei et al., 2009) published in Arthritis Research & Therapy was the largest such study. Chicken type II collagen (CCII) is a protein extracted from the cartilage of chicken breast; a 24-week, double-blind, double-dummy, randomized, methotrexate (MTX)-controlled study was conducted to evaluate the efficacy and safety of CCII in RA; 503 RA patients were included; patients received either 0.1 mg daily of CCII (n=326) or 10 mg once a week of MTX (n=177) for 24 weeks.

Four hundred fifty-four patients (94.43%) completed the 24-week follow-up; in both groups there were decreases in pain, morning stiffness, tender joint count, swollen joint count, HAQ, and assessments by investigator and patient, and all differences were statistically significant. However, at 24 weeks, 41.55% of patients in the CCII group and 57.86% in the MTX group met the ACR-20 improvement criteria, and 16.89% and 30.82% respectively met the ACR-50 criteria; both response rates in the CCII group were lower than those of the MTX group, and this difference was statistically significant (P < 0.05).

Evidence strength (RA): The Wei et al. phase III trial is the most rigorous evidence and shows that CCII (0.1 mg/day) produced statistically significant improvements across RA disease activity measures, but the response rates were inferior to methotrexate, a standard disease-modifying drug. CCII is not established as a replacement for standard RA pharmacotherapy.

5.3 Exercise-Related Joint Discomfort in Healthy Subjects

The effect of UC-II in non-arthritic individuals experiencing exercise-induced joint pain was assessed in a 2013 randomized, double-blind, placebo-controlled trial (Lugo et al., Journal of the International Society of Sports Nutrition). This study was conducted in healthy subjects who had no prior history of arthritic disease or joint pain at rest but experienced joint discomfort with physical activity; 55 subjects were randomized to receive placebo (n=28) or UC-II (40 mg daily, n=27) for 120 days; joint function was assessed by changes in degree of knee flexion and extension as well as time to experiencing and recovering from joint pain following strenuous stepmill exertion.

Evidence strength (exercise-related joint pain): This is a small single study (n=55) of relatively short duration. The findings suggest potential utility in non-OA populations but require replication in larger independent trials before firm conclusions can be drawn.

5.4 Skin Aging and Dermal Parameters

A pilot open-label study (Schwartz & Park, 2012, Clinical Interventions in Aging) investigated BioCell Collagen's effects on facial aging signs. In a pilot open-label study of BioCell Collagen® (BCC), which contains a naturally occurring matrix of hydrolyzed collagen type II and low-molecular-weight hyaluronic acid and chondroitin sulfate, in 26 healthy females with visible signs of aging, daily supplementation with 1 g of BCC for 12 weeks led to a significant reduction of skin dryness/scaling (76%, P=0.002) and global lines/wrinkles (13.2%, P=0.028) as measured by visual/tactile score. Additionally, a significant increase in the content of hemoglobin (17.7%, P=0.018) and collagen (6.3%, P=0.002) in the skin dermis was observed after 6 weeks of supplementation. This pilot study is limited by its open-label design and small sample size.

A subsequent 12-week randomized, double-blind, placebo-controlled trial (published 2019) addressed these limitations with a larger sample. A 12-week, randomized, double-blind, placebo-controlled trial of 128 female subjects aged 39–59 was conducted; twice-daily oral administration of a supplement containing 500 mg of a naturally occurring matrix of collagen type II peptides, hyaluronic acid, and chondroitin sulfate derived from chicken sternal cartilage, or placebo, was the intervention. Dietary supplementation significantly reduced facial lines and wrinkles (p=0.019), crow's feet lines/wrinkles (p=0.05), increased skin elasticity (p=0.05), cutaneous collagen content (p=0.001), and improved indicators of youthful skin appearance and wrinkle width (p=0.046), and decreased skin dryness and erythema, compared to placebo. There was no difference between supplement and placebo for skin surface water content or retention; the supplement was well tolerated with no reported adverse reactions.

Evidence strength (skin aging): The larger RCT provides controlled evidence for effects on specific skin parameters in women aged 39–59. Limitations include enrollment restricted to women, making generalization to men or other age groups uncertain; the supplement was well tolerated with no reported adverse reactions, and study limitations include the use of only female participants who were 39 years of age or older, making generalization to younger age groups impossible. Skin aging endpoints were measured by validated but still relatively subjective or technique-dependent instruments.

5.5 Preclinical (Animal and In Vitro) Evidence

Several animal models have contributed mechanistic and proof-of-concept data. The aim of one study was to determine the ability of undenatured native chicken type II collagen (UC-II) to prevent excessive articular cartilage deterioration in a rat model of OA; surgery produced moderate OA at the medial tibial plateau; study results demonstrated that a clinically relevant daily dose of UC-II applied immediately after injury can improve the mechanical function of the injured knee and prevent excessive deterioration of articular cartilage. Animal studies on the use of UC-II have shown a positive effect on preventing cartilage damage and arresting the advancement of the disease process.

In the context of rheumatoid arthritis models, administration of CCII (10, 20, 40 μg/kg/day, days 15–22) could significantly reduce synovial hyperplasia, lymphatic follicle hyperplasia, and inflammatory cells infiltration of mesenteric lymph node lymphocytes in collagen-induced arthritis rats.

Oral CS, cartilage powder, and type II collagen peptides in rat models could increase athletic ability and reduce inflammatory cytokine levels including prostaglandin E2, TNF-α, IL-1β, IL-6, and IL-17; CS displayed the best treatment effect against OA; CS could significantly improve cartilage tissue morphology and reduce OA score; oral CS slowed down the development of OA by modulating gut microbiota.

Note on evidence grade: All animal and in vitro findings are preliminary. They inform plausible mechanisms but cannot be directly extrapolated to human therapeutic outcomes.

6. Body Systems and Health Areas of Association

Musculoskeletal system (joint cartilage): The most clinically investigated area. Avian cartilage preparations, particularly UC-II®, are associated with joint pain reduction, improved function, and range of motion in OA and RA. Native type II collagen derived from chicken sternal cartilage possibly acts by desensitizing the T-cell-mediated attack on native type II collagen; animal studies have shown a positive effect on preventing cartilage damage and arresting the advancement of the disease process.
Immune system: The oral tolerance mechanism positions avian type II collagen as an immune-modulating agent. Downregulation of the immune response to CII may help prevent the resulting destructive arthritis; oral administration of CII is an established procedure for inducing peripheral immune tolerance, which suppresses autoimmune responses in RA.
Integument (skin): Hydrolyzed preparations are associated with improvements in skin collagen content, elasticity, and reduction of wrinkles and dryness in clinical trials. Dietary supplementation of chicken sternal cartilage extract supports the accumulation of types I/III collagen in skin to promote increased elasticity and reduced skin wrinkling.
Gut microbiota: A preclinical finding suggests that chondroitin sulfate from chicken cartilage may modulate intestinal microbial communities, contributing to its anti-OA effects. Oral CS slowed down the development of OA by modulating gut microbiota. This is a preliminary observation requiring human validation.

7. Dosage Forms and Dosages Reported in Clinical Studies

Dosages vary substantially based on preparation type and intended use:

Undenatured type II collagen (UC-II®) — joint applications: Fifty-five subjects were randomized to receive placebo or UC-II at 40 mg daily for 120 days. In the 191-subject multicenter OA trial, subjects received a daily dose of UC-II (40 mg), GC (1500 mg G and 1200 mg C), or placebo for 180 days. The 40 mg daily dose is consistently the studied dose across human trials of UC-II®. Each 40 mg capsule of UC-II material in the clinical study provided 10.4 ± 1.3 mg of native type II collagen.
Undenatured type II collagen — immunological (RA) applications: Type II collagen, when used for its effects on the immune system in rheumatoid arthritis, is used in very small amounts, from 0.02 mg to 10 mg per day. In the Wei et al. phase III RA trial, patients received 0.1 mg daily of CCII for 24 weeks.
Desiccated avian sternal cartilage powder (Kolla2™): The compositions are orally administered to humans in need of cartilage cell repair in a daily dietary supplement dosage of between about 2,400 mg and 3,600 mg.
Hydrolyzed chicken sternal cartilage extract (BioCell Collagen®) — OA application: Research shows that taking 1 gram of BioCell Collagen by mouth twice daily for up to 10 weeks reduces pain, increases physical activity, and reduces the need for pain medication in people with osteoarthritis.
Hydrolyzed extract (BioCell Collagen®) — skin aging application: Early research shows that taking 500 mg of BioCell Collagen by mouth twice daily for 12 weeks improves skin dryness and reduces lines and wrinkles in women with visible signs of aging skin. In the pilot open-label skin study, 1 g daily of BCC for 12 weeks was administered to 26 healthy females, leading to significant reduction of skin dryness/scaling and global lines/wrinkles.

8. Safety Considerations

8.1 General Tolerability

Across the clinical trials reviewed, avian cartilage preparations have demonstrated a favorable safety profile at the doses tested. In clinical investigations running for 180 days or longer, UC-II® has demonstrated a high safety profile, with tolerability and side effects typically comparable to placebo. Mild stomach upset is occasionally reported. In the large 191-subject OA trial, safety outcomes were similar for all three groups (UC-II, glucosamine/chondroitin, and placebo). In the skin-aging RCT, the supplement was well tolerated with no reported adverse reactions.

For the BioCell Collagen® hydrolyzed form, BioCell Collagen is likely safe for adults when taken by mouth short-term in daily doses of 2 grams or less.

8.2 Potential Interaction with Immunosuppressive Medications

Because undenatured type II collagen exerts its proposed effects through an immune-mediated mechanism, a relevant theoretical safety consideration exists regarding immunomodulatory drugs. There are no widespread, severe drug interactions documented with UC-II®; however, since it works by engaging the immune system, patients taking immunosuppressive medications should exercise caution.

8.3 Comparison to Risk Profile of Standard Treatments

The safety advantage of avian cartilage supplements is frequently contextualized against NSAID use. Classical medication treatments of OA include acetaminophen, nonsteroidal anti-inflammatory drugs, and glucosamine sulfate for abatement of pain and symptoms in the clinical setting; however, long-term oral NSAIDs can cause a series of side effects, including renal impairment and gastric ulceration.

8.4 Avian Protein Allergy Consideration

Avian cartilage preparations are derived from chicken tissue and therefore pose a potential risk to individuals with documented hypersensitivity to poultry proteins or chicken-derived products. This is an inherent biological consideration, not merely a labeling formality. The Wei et al. RA trial noted that the exclusion criteria of at least one trial included history of allergic reaction to products used in the study.

8.5 RA: Not Equivalent to Standard of Care

In the context of rheumatoid arthritis, the clinical trial data make clear that CCII is not a replacement for established disease-modifying therapy. At 24 weeks, ACR-20 and ACR-50 response rates in the CCII group were lower than those of the MTX group, and this difference was statistically significant. Individuals with active, diagnosed RA who discontinue or avoid standard pharmacotherapy in favor of avian collagen supplementation therefore accept a clinically meaningful difference in expected disease control.

8.6 Pregnancy and Lactation

For the most part, there is not enough evidence to know whether BioCell Collagen is safe for adults when applied to the skin, and not enough is known about its safety during pregnancy and breastfeeding. This knowledge gap applies analogously to other avian cartilage supplement forms, as no adequate controlled studies in pregnant or lactating populations have been published.

References

Health Conditions

Health conditions that Avian cartilage may help support.

Cartilage HealthScientific
Avian (chicken sternal) cartilage is the primary commercial source of undenatured type II collagen (UC-II), chondroitin sulfate, and hyaluronic acid. UC-II at 40 mg/day induces oral tolerance via gut-associated lymphoid tissue, reducing T-cell–mediated degradation of articular cartilage. A double-blind RCT (Crowley et al., 2009, n=52 knee OA) found UC-II from avian cartilage superior to glucosamine+chondroitin on all three WOMAC subscales at 90 days. A 2022 systematic review confirmed type II collagen peptides as consistently efficacious across multiple OA trials.
Connective Tissue HealthScientific
Avian (chicken) sternal cartilage is the primary commercial source of undenatured type II collagen (UC-II) and native glycosaminoglycans. In a double-blind RCT, UC-II from avian cartilage at 40 mg/day produced significantly greater reduction in OA pain than glucosamine/chondroitin combined. The immunological mechanism involves oral tolerance induction to suppress cartilage-attacking immune responses.
Flexibility & MobilityScientific
Avian (chicken) sternum cartilage is the primary commercial source of undenatured type II collagen (UC-II), which has been studied in multiple RCTs for OA and joint health. UC-II at 40 mg/day operates via oral tolerance mechanisms and has been shown in clinical trials to improve joint comfort and function, including in athletes with activity-related knee pain. It outperforms glucosamine+chondroitin in some head-to-head studies.

Body Systems

Body systems that Avian cartilage may help support.

No body systems available.