Collagen: Which Type (I, II, III) Is Best for Skin, Joints and Bones?

Collagen is the most abundant protein in connective tissue and one of the key structural components of skin, bones, tendons, and cartilage. Supplements most commonly contain type I, II, or III collagen, but the “best” type depends on what the goal is: supporting the skin, joints (cartilage), or bones [1], [2].

Important: Collagen supplements are not medications, and claims on product labels should be distinguished from the results of clinical research. In the United States, the U.S. Food and Drug Administration does not approve dietary supplements as drugs before they reach the market, so a marketing claim by itself is not evidence of clinical efficacy [13].

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Types I, II and III: Where Are They Found in the Body, and What Does That Mean in Practice?

• Type I: dominant in the skin and bones, and also present in tendons and ligaments. This is why type I is most often associated with “skin + bones” [1], [2].
• Type II: characteristic of cartilage, the tissue that covers joint surfaces and cushions mechanical load. It is most often associated with joint support [1], [4].
• Type III: often found together with type I in the skin and blood vessels and contributes to the structure of soft tissues. In supplements, it is often combined with type I, particularly in bovine or marine collagen products [1].

In practice: a label stating “type I & III” is most often associated with skin support and potentially bone support, while “type II” more often refers to joint cartilage.

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Collagen Form: Hydrolyzed Peptides vs. Native (Undenatured) Type II

In practice, two forms are encountered most often:

1. Hydrolyzed collagen / collagen peptides (collagen hydrolysate, collagen peptides)
   These proteins are broken down into smaller peptides for easier use and probably better absorption. They are used most extensively in skin studies, but also in studies of joint pain and bone-related markers or outcomes [5], [6], [7].
2. Native (undenatured) type II collagen (often labeled UC-II)
   This is not a “collagen peptide,” but a specific form of type II collagen used in much smaller doses, typically tens of milligrams, and most often studied for joint function and symptoms [8], [9].

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What Is Best for the Skin?

The largest amount of clinical evidence for skin is available for hydrolyzed collagen peptides, most often from sources rich in type I collagen, frequently with type III as well. Systematic reviews and meta-analyses of clinical trials suggest improvements in parameters such as skin hydration and elasticity compared with placebo, although results vary among studies [3], [5].

A frequently cited randomized, placebo-controlled study found improved skin elasticity in women taking 2.5 g or 5 g of collagen hydrolysate daily for 8 weeks compared with placebo [6]. More recent randomized studies have also assessed biometric skin parameters and reported improvements in certain measurements, although study quality and design vary [10].

Which Label Is Relevant for Skin?

• “Hydrolyzed collagen / collagen peptides” (often “type I” or “type I & III”) [5], [6]

Realistic expectations: effects are usually moderate and require consistency, most often 8-12+ weeks in studies [5], [6].

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What Is Best for Joints?

There are two approaches here, supported by different types of evidence:

Native (Undenatured) Type II Collagen (UC-II): Focus on Cartilage and Function

Randomized studies report improvements in certain outcomes related to joint function and symptoms at doses of about 40 mg/day, with generally good tolerability [8], [9].

When Does This Make Sense?

This option makes the most sense when the main goal is joint cartilage, mobility, or symptoms and the product clearly states undenatured type II with a dose in milligrams rather than grams [8], [9].

Hydrolyzed Collagen Peptides: Focus on Pain and Function

Randomized controlled trials and meta-analyses in osteoarthritis, a degenerative joint disease, suggest reductions in pain and improvements in functional scores such as WOMAC compared with control, while also noting substantial heterogeneity among studies in products, doses, and treatment duration [7], [11]. Studies in physically active people with activity-related joint pain have also reported improvement during 24 weeks of supplementation [12].

Which Label Is Relevant for Joints?

• For OA or general joint support: “collagen hydrolysate / peptides” (usually dosed in grams) or “undenatured type II (UC-II)” (dosed in milligrams) [8], [11].

People taking pain medications, such as NSAIDs (nonsteroidal anti-inflammatory drugs including ibuprofen or naproxen), should not change treatment on their own; a supplement is not a substitute for a treatment plan [13].

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What Is Best for Bones?

Bones are rich in type I collagen, so specific collagen peptides, mainly type I, have been studied as dietary supplements, especially in people with lower bone mineral density.

A randomized controlled trial in postmenopausal women with reduced BMD found that supplementation with specific collagen peptides may increase BMD and favorably affect markers of bone metabolism compared with placebo [14]. Earlier studies have also examined biochemical markers of bone remodeling during collagen-hydrolysate supplementation [15].

Which Label Is Relevant for Bones?

• “Collagen peptides / hydrolyzed collagen” (often type I) [14]
• However, the foundation for bone health remains adequate protein intake, vitamin D and calcium, together with weight-bearing exercise; collagen may be an addition, not the foundation [14].

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How Much Should Be Taken, and for How Long?

Doses vary among studies, but hydrolyzed collagen is commonly used in gram-level doses, for example 2.5-10 g/day, whereas undenatured type II is typically used in doses of tens of milligrams [6], [8]. As a practical reference, Health Canada lists dosing ranges for hydrolyzed collagen, including approximately 2.6-10 g/day for certain uses, and provides cautionary notes for specific populations [15].

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Safety and Who Should Be Cautious

Collagen is generally well tolerated in studies; meta-analyses in osteoarthritis report that collagen derivatives did not increase the risk of adverse events compared with control within the included studies [11]. Mild gastrointestinal symptoms such as bloating or nausea may still occur in some people.

Caution:

• Pregnancy/breastfeeding: consultation with a healthcare professional is recommended, particularly with higher daily doses, as also stated in the Health Canada monograph [15].
• Allergies/source: marine collagen should be avoided in people with fish allergy; bovine or porcine sources should be considered according to individual restrictions.
• Regulation and quality: in the United States, supplements are not approved as drugs before entering the market. The U.S. Food and Drug Administration (FDA) regulates supplements differently from drugs, so it is important to choose reputable manufacturers and products with clear labeling [13].

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What to Remember

Skin (elasticity/hydration): most often hydrolyzed collagen peptides, usually type I and often with type III, taken consistently for 8-12+ weeks [5], [6].

• Joints (cartilage/mobility): undenatured type II (UC-II, around 40 mg/day) may be considered; alternatively, collagen peptides in gram doses are used for pain and function, particularly in OA [8], [11].
• Bones (BMD/markers): specific collagen peptides, mainly type I, may be used as an addition to the fundamentals of bone health: protein, vitamin D, calcium, and exercise [14].

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Sources

[1] Nezwek TA, et al. Physiology, Connective Tissue. StatPearls (NCBI Bookshelf) 2024.

https://www.ncbi.nlm.nih.gov/books/NBK542226/

[2] Amirrah IN, et al. A Comprehensive Review on Collagen Type I Development of Biomaterials for Tissue Engineering: From Biosynthesis to Bioscaffold 2022.

https://pmc.ncbi.nlm.nih.gov/articles/PMC9496548/

[3] Pu SY, et al. Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis 2023.

https://pmc.ncbi.nlm.nih.gov/articles/PMC10180699/

[4] Chang LR, et al. Anatomy, Cartilage. StatPearls (NCBI Bookshelf) 2024.

https://www.ncbi.nlm.nih.gov/books/NBK532964/

[5] de Miranda RB, Weimer P, Rossi RC. Effects of Hydrolyzed Collagen Supplementation on Skin Aging: A Systematic Review and Meta-Analysis 2021.

https://onlinelibrary.wiley.com/doi/10.1111/ijd.15518

[6] Proksch E, et al. Oral Supplementation of Specific Collagen Peptides Has Beneficial Effects on Human Skin Physiology: A Double-Blind, Placebo-Controlled Study 2014.

https://pubmed.ncbi.nlm.nih.gov/23949208/

[7] García-Coronado JM, et al. Effect of Collagen Supplementation on Osteoarthritis Symptoms: A Meta-Analysis of Randomized Placebo-Controlled Trials 2019.

https://pubmed.ncbi.nlm.nih.gov/30368550/

[8] Lugo JP, et al. Undenatured Type II Collagen (UC-II®) for Joint Support: A Randomized, Double-Blind, Placebo-Controlled Study in Healthy Volunteers 2013.

https://pmc.ncbi.nlm.nih.gov/articles/PMC4015808/

[9] Gupta A, Maffulli N. Undenatured Type II Collagen for Knee Osteoarthritis 2025.

https://pmc.ncbi.nlm.nih.gov/articles/PMC12010644/

[10] Demir-Dora D, et al. The Efficacy and Safety of CollaSel Pro® Hydrolyzed Collagen Peptide Supplementation Without Addons in Improving Skin Health in Adult Females 2024.

https://pmc.ncbi.nlm.nih.gov/articles/PMC11432272/

[11] Lin CR, et al. Analgesic Efficacy of Collagen Peptide in Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials 2023.

https://pmc.ncbi.nlm.nih.gov/articles/PMC10505327/

[12] Clark KL, et al. 24-Week Study on the Use of Collagen Hydrolysate as a Dietary Supplement in Athletes With Activity-Related Joint Pain 2008.

https://pubmed.ncbi.nlm.nih.gov/18416885/

[13] U.S. Food and Drug Administration (FDA). FDA 101: Dietary Supplements Accessed 2026.

https://www.fda.gov/consumers/consumer-updates/fda-101-dietary-supplements

[14] König D, et al. Specific Collagen Peptides Improve Bone Mineral Density and Bone Markers in Postmenopausal Women: A Randomized Controlled Study 2018.

https://pmc.ncbi.nlm.nih.gov/articles/PMC5793325/

[15] Health Canada. Hydrolyzed Collagen: Natural Health Product Monograph 2024.

https://webprod.hc-sc.gc.ca/nhpid-bdipsn/dbImages/mono_hydrolyzed-collagen_english.pdf

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Health Disclaimer: This content is for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before starting or changing any supplement, especially if you are pregnant, breastfeeding, have a medical condition, or take medication.

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