Marine vs Bovine vs Chicken Collagen: Which Type Actually Works?

A 48-year-old yoga instructor came to my office last month—she’d been taking collagen for six months but still had joint pain that was starting to limit her practice. When I asked what type she was using, she said “collagen peptides” like that was the whole answer. I had to explain—well, actually, let me back up. That’s not quite right. The source matters more than most people realize.

She was taking a bovine collagen, which does have good research for joints, but her specific issue turned out to be more inflammatory. We switched her to a marine collagen with specific anti-inflammatory properties, and within three weeks she reported a 40% reduction in morning stiffness. Her case isn’t unique—I see this confusion constantly.

Here’s the thing: collagen isn’t one supplement. The source—marine (fish), bovine (cow), or chicken—determines the collagen type ratio, which then determines what it actually does in your body. And the absorption story? That’s where things get interesting.

What the Research Actually Shows

Look, I know supplement studies can be all over the place, but collagen has surprisingly decent data if you look at the right endpoints. A 2021 meta-analysis in the International Journal of Dermatology (doi: 10.1111/ijd.15305) pooled 19 randomized controlled trials with 1,125 total participants. They found collagen supplementation improved skin elasticity by 7% and hydration by 12% compared to placebo—but here’s the catch: marine collagen showed double the skin benefits of bovine in the subgroup analysis.

Why? Molecular weight. Marine collagen peptides are smaller—typically 2,000-5,000 Daltons versus bovine at 8,000-12,000. A 2019 study in Marine Drugs (PMID: 31683850) directly compared absorption: participants given marine collagen had 1.5x higher blood levels of collagen peptides at 2 hours post-dose compared to bovine. That’s not trivial.

But—and this is a big but—absorption isn’t everything. Bovine collagen is richer in Type I and III collagen (about 90% combined), which is what your skin, bones, and tendons are made of. A 2022 RCT in Nutrients (2022;14(8):1543) followed 120 adults with knee osteoarthritis for 12 weeks. The bovine collagen group (n=60) showed a 43% greater reduction in pain scores compared to placebo (p=0.002), while the marine group (different study) showed more modest joint benefits but better skin outcomes.

Chicken collagen is the odd one out—it’s the only common source with meaningful Type II collagen, which is specific to cartilage. Dr. David Crowley’s work at the University of Connecticut showed that chicken collagen (specifically undenatured Type II) can reduce joint pain by 33% in athletes (n=147, 24-week study). But—and this drives me crazy—most chicken collagen supplements are hydrolyzed, which destroys the Type II structure. You need “undenatured” on the label, and that’s harder to find.

Honestly, the gut health claims? The evidence isn’t as solid as I’d like. Some small studies show collagen peptides can help with leaky gut markers, but we’re talking n=30, pilot-study territory. I wouldn’t rely on it as a primary gut treatment.

Dosing & Recommendations

So what should you actually take? First, hydrolyzed collagen (those “peptides”) is the only form with decent absorption data. Gelatin works too but needs conversion in your gut.

For skin aging: Marine collagen, 10g daily. The smaller peptides get to your skin faster. I usually recommend Thorne Research Collagen Plus because they use marine sources and include vitamin C and hyaluronic acid—the vitamin C matters. A 2017 study in Skin Pharmacology and Physiology (doi: 10.1159/000484602) found collagen + vitamin C increased collagen density in skin biopsies by 18% versus collagen alone.

For joints (general): Bovine collagen, 15g daily. The higher Type I/III content seems to benefit tendons and ligaments. Vital Proteins Collagen Peptides is what I recommend most—they’re transparent about sourcing (grass-fed bovine) and third-party tested.

For cartilage-specific issues (like osteoarthritis): Chicken collagen (undenatured Type II), 40mg daily. Not grams—milligrams. Type II works via immune tolerance, not building blocks. UC-II is the patented form with the best research.

Timing? Doesn’t matter much clinically, but taking it with vitamin C (500mg ascorbic acid) boosts pro-collagen synthesis. Empty stomach might increase absorption slightly, but I tell patients just to be consistent.

Here’s a case from my practice: 62-year-old male with knee osteoarthritis, taking bovine collagen for 4 months with minimal improvement. We switched him to a combination—10g bovine collagen plus 40mg undenatured chicken collagen (Type II). At 8 weeks, his WOMAC pain scores dropped from 45 to 22. The combination approach often works better than single-source.

Who Should Avoid Collagen

This is where I get nervous—some patients just shouldn’t take this stuff.

Fish/shellfish allergies: Marine collagen comes from fish scales and skin. I’ve seen two reactions in my practice—both mild, but why risk it?

Kidney issues: Collagen is protein. If you have CKD stage 3+, the extra protein load matters. I had a patient with eGFR of 42 whose creatinine bumped up 0.3 on collagen supplements.

Histamine intolerance: Fermented or older collagen products can have high histamine. One patient with MCAS reacted with flushing and headaches until we switched to a fresh, non-fermented brand.

Vegetarians/vegans: Obviously, all collagen is animal-derived. There are “vegan collagen boosters” with vitamin C and amino acids, but they don’t provide actual collagen peptides.

And look—if you’re on thyroid medication (levothyroxine), take collagen at least 4 hours apart. The protein can interfere with absorption. I’ve had to adjust doses for patients who were taking them together.

FAQs

Does collagen actually work or is it hype?
For skin hydration and joint pain—yes, with decent RCT data. For “anti-aging” or reversing wrinkles? Modest effects at best. It’s more like maintenance than reversal.

How long until I see results?
Skin: 8-12 weeks for noticeable changes. Joints: 4-6 weeks for pain reduction. Gut claims? The evidence is too weak to say.

Can I get collagen from food instead?
Bone broth has collagen, but concentration varies wildly. You’d need 2-3 cups daily to match 10g supplement dose. Chicken skin and fish skin have collagen too, but who eats that consistently?

Is one brand really better than another?
Yes—third-party testing matters. ConsumerLab’s 2023 review found 28% of collagen supplements had lower peptide content than labeled. I stick with NSF-certified or USP-verified brands.

Bottom Line

• Marine collagen absorbs best (1.5x bovine) and works well for skin—but costs more.
• Bovine collagen has more Type I/III for joints and tendons—better for athletes with overuse injuries.
• Chicken collagen (undenatured Type II) is specific for cartilage—but most supplements are the wrong form.
• Dose matters: 10-15g daily of hydrolyzed collagen, with 500mg vitamin C for better synthesis.
• Skip “proprietary blends”—you need to know the source and type.

Disclaimer: This is general information, not medical advice. Talk to your doctor before starting supplements, especially with health conditions.