Collagen gets lumped into a single category far too often. In reality, the human body uses more than 28 distinct types of collagen, each with a specific role. When knee pain, stiffness, or reduced mobility enter the picture, the type of collagen you choose matters far more than the label on the bottle.
Here’s what the research shows about the main collagen types, how they differ, and which ones truly support knee health.
The Main Types of Collagen — and What They Do
Type I Collagen
Type I collagen makes up about 90% of the collagen in the human body. You’ll find it in skin, bones, tendons, and ligaments. It provides structural strength, but it does not dominate cartilage tissue. That makes it less specialized for knee support.
Type II Collagen
Type II collagen accounts for roughly 90% of the collagen found in cartilage. It gives cartilage its ability to withstand compression and repetitive movement. Because cartilage cushions the knee joint, Type II collagen plays a central role in joint function and mobility.
Type III Collagen
Type III collagen often appears alongside Type I. It supports elasticity in tissues like skin, lungs, and blood vessels. It helps maintain tissue flexibility, but it does not directly support cartilage structure.
Type IV Collagen
Type IV collagen forms thin, sheet-like membranes in tissues such as skin and kidneys. It supports cell attachment and tissue organization rather than joint cushioning.
Type V Collagen
Type V collagen regulates how Type I collagen fibers form and organize. It appears in connective tissues, including skin and bone, but it does not serve as a primary cartilage component.
Type X Collagen
Type X collagen appears mainly in cartilage during bone growth and calcification. It supports skeletal development rather than everyday joint mobility in adults.
Which Collagen Is Best for Knees?
Type II collagen stands out as the most relevant for knee health.
Cartilage depends on it. Without enough functional Type II collagen, cartilage loses resilience, friction increases, and movement becomes less comfortable.
Research consistently shows that Type II collagen supplementation provides the most meaningful support for knee pain, stiffness, and joint function, especially in people with age-related wear or osteoarthritis-related changes.
Two Forms of Type II Collagen — Very Different Roles
Hydrolyzed (Denatured) Collagen Peptides
Hydrolyzed collagen breaks down collagen into smaller peptide chains. The body absorbs these peptides quickly, often within hours. They act as building blocks that support cartilage matrix production and overall joint tissue maintenance.
Clinical research shows that 2.5 to 10 grams per day supports knee comfort and function. A 2025 study found that 3 grams daily for 180 days significantly reduced knee pain and improved physical function in people with knee osteoarthritis.
This form is best for people seeking general joint support and cartilage regeneration.
Undenatured (Native) Type II Collagen
Undenatured Type II collagen keeps its original triple-helix structure. It works through a process known as oral tolerance, which helps calm immune responses that contribute to cartilage breakdown.
Despite the much smaller dose — typically 40 mg daily — studies show this form can match or outperform glucosamine and chondroitin for knee pain and stiffness over time. Results often appear after several months of consistent use.
This form suits people dealing with chronic inflammation or immune-related joint stress.
How the Two Forms Compare
Absorption: Hydrolyzed collagen absorbs quickly; undenatured collagen works gradually
Mechanism: Hydrolyzed collagen provides structural building blocks; undenatured collagen supports immune balance
Timeline: Hydrolyzed collagen may show effects in weeks; undenatured collagen often takes longer
Dosage: Grams versus milligrams
Best Use: Structural joint support versus inflammation-driven joint issues
Both forms show strong evidence for knee support. The best choice depends on the underlying issue.
Supporting Collagen Where It Counts
Collagen doesn’t work in isolation. Vitamin C plays a critical role in collagen synthesis, helping the body build and maintain connective tissue. Foods like citrus, strawberries, red bell peppers, and tomatoes support that process naturally.
Many people also pair collagen with ingredients that support joint comfort and movement, including hyaluronic acid and other structural nutrients.
Where Supplements Fit In
For people focused specifically on joint comfort, flexibility, and everyday movement, collagen often works best as part of a broader joint-support strategy.
That’s where supplements such as MobilityMD come in. MobilityMD focuses on supporting joint mobility and physical comfort with thoughtfully selected ingredients that complement lifestyle choices like regular movement and strength maintenance.
You can learn more about MobilityMD at https://www.mymobilitymd.com.
Supplements don’t replace movement or healthy habits. They support the biological systems that make staying active more manageable over time.
The Bottom Line
Not all collagen supports knees equally. Type II collagen — in hydrolyzed or undenatured form — plays the most direct role in cartilage health and knee function. Choosing the right form, using evidence-backed dosing, and supporting collagen production with proper nutrition makes the difference.
Joint health builds gradually. Consistency, movement, and smart biological support matter more than quick fixes.
Medical Disclaimer
This article is for informational and educational purposes only and does not constitute medical advice. It is not intended to diagnose, treat, or prevent any medical condition. Individuals should consult a qualified healthcare professional before starting any dietary supplement, especially if they have a medical condition or take medications.
FDA Disclaimer
The Food and Drug Administration has not evaluated dietary supplements mentioned in this article. These products are not intended to diagnose, treat, cure, or prevent any disease.
FTC Disclosure
Kathryn Munoz, PhD, MPH, and Keith Ablow, MD, are co-founders of companies that develop and market dietary supplements, including products referenced in this article. They may receive financial benefit from the sale of these products. Individual results may vary.
