Why Cod Skin? The Story Behind Our White Synergy Collagen | Wellinder

When we were figuring out which collagen to use, one question kept nagging at me."Wait, which fish should our collagen actually come from?"

We take this product every day. It felt a little odd to call it "great collagen" without knowing exactly which fish it came from.

So we came up with three criteria for choosing our collagen ingredient.

First, we wanted to know exactly where it came from.
"Premium fish collagen" on its own wasn't enough. We wanted to know the species and the country of origin.

Second, we wanted to see the size of the collagen peptides, not just the amount.
Collagen can be broken down into smaller peptides through hydrolysis. Instead of relying on a vague label like "ultra-low molecular," we wanted actual data on molecular weight.

Third, we wanted protein content and quality backed by numbers.
Anyone can say "high quality." We wanted to see exactly how much protein was in the ingredient, and what the heavy metal and microbial test results showed.

And there was one ingredient that matched all three.

Saffron cod.

Not a name you hear every day, right?

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01. A fish from cold northern waters

Saffron cod's scientific name is Eleginus gracilis.

It's a member of the cod family that lives in the cold waters of the North Pacific.

Despite the name, it has nothing to do with the yellow spice we cook with.

It's smaller than the large cod most of us picture, with a greyish-brown body and a silvery belly.

It lives close to the coast and around river mouths, and moves with the seasons.

It comes closer to shore in autumn and winter, then heads back out to sea in spring and summer to feed.

That's the fish we chose for our collagen. But what really caught our attention was its skin.

02. So why the skin?

When you think of eating fish, you usually think of the flesh first.

But when it comes to collagen, the story changes.

Fish skin is an important source of collagen.

Our interest in cod skin wasn't just because it contains collagen.

What caught our attention was that collagen peptides from cod skin have actually been studied in relation to skin.

A study that compared five types of collagen

 

 

A 2025 study published in Food & Function compared collagen peptides from five different sources: cod skin, tilapia skin, cowhide, pig skin and chicken bone.

The researchers applied each peptide to cells damaged by UV exposure and looked at several markers related to skin damage.

In this cell study, cod-derived peptides showed the most pronounced effects on the skin-damage markers evaluated.

But that wasn't the end of it.

The researchers went on to test the cod peptide in humans.

In an eight-week trial comparing cod peptides with a placebo, the researchers reported improvements in skin hydration, elasticity and wrinkle-related measures.

This is the part that stood out to us.

Cod skin wasn't just a source of collagen. It was an ingredient that had actually been studied for its effect on human skin.

The study gave us another reason to take a closer look at cod-skin-derived collagen.

03. Beyond the Claims: What Did the Test Results Actually Show?

"Ultra-low molecular collagen." "High-quality collagen."

You see phrases like this all the time.

But we didn't want to judge an ingredient on description alone.

We wanted to know what its actual properties were, and what the test results showed.

So we looked closely at two certificates of analysis for the saffron-cod-derived collagen we chose.

Three things mattered most.

① 300 Da — why we paid attention to smaller peptides

 

 

Collagen starts out as a large protein.

Break it into smaller pieces, and you get collagen peptides.

But does making it smaller actually relate to absorption?

A 2016 human study found that after participants ingested a collagen tripeptide with an average molecular weight of about 300 Da, collagen-derived peptides were detected in the blood. The researchers reported that collagen in tripeptide form may be absorbed more efficiently by the body.

Our saffron cod ingredient's certificates of analysis list a molecular weight specification of 300 Da, and both batches we reviewed met that specification

② 98%+ protein — checking what's inside

Collagen is a key structural protein in skin.

It's also important in connective tissue like bone, tendons and cartilage.

But does every collagen ingredient have the same protein content?

Not necessarily.

An ingredient can contain moisture and other components alongside protein.

Since collagen peptides are the key ingredient we wanted to deliver, knowing exactly how much protein it contains mattered to us.

So we checked the certificates.

Protein content in the two batches we reviewed was 98.40% and 98.33%.

In plain terms, roughly 98g out of every 100g of the ingredient is protein.

③ Quality testing — because it's something you take every day

The last thing we checked was quality testing.

Even the same ingredient can vary batch to batch depending on when it was manufactured. So rather than relying on a single test result, we looked at results across different batches.

In both certificates of analysis we reviewed, heavy metal test results met the specifications listed on the certificate.

E. coli and Salmonella tests both came back negative.

Molecular weight and protein content can look great on paper, but for something you take every day, checking quality and safety wasn't optional.

Only after going through each of these conditions did we feel ready to introduce this ingredient to you.

That's why we chose this saffron-cod-derived collagen peptide.

And why every stick of White Synergy Collagen contains 2,500 mg of it.

A note on the research and test data: The studies cited above were not conducted on Wellinder's collagen ingredient or finished product. The molecular weight specification, protein content and quality test results are based on certificates of analysis for two batches of our collagen ingredient, not the finished product.

References:

• He L, et al. Anti-photoaging activity of cod peptides: structural characterisation and clinical validation. Food Funct. 2025. DOI: 10.1039/D5FO02080H
• Yamamoto S, Deguchi K, Onuma M, Numata N, Sakai Y. Absorption and urinary excretion of peptides after collagen tripeptide ingestion in humans. Biol Pharm Bull. 2016;39(3):428-434.

Allergen information: Contains fish and milk.