What Our Tallow Tests Tell Us—and What They Don’t

For years, I repeated something nearly everyone in the tallow world seemed to accept as fact: grassfed tallow was rich in vitamins A, D, E and K.

It sounded reasonable. It was repeated everywhere. And because water buffalo meat has such an interesting nutritional profile, I assumed the fat must be remarkable, too.

But assumptions are not evidence.

So I sent our tallow to the laboratory.

What came back changed the way I talk about tallow, the questions I ask and, ultimately, the way I formulate skincare.

Not because the reports proved that tallow is a miracle. They didn’t.

They showed me something more useful: the raw material was far more complex—and far more variable—than the internet had led us to believe.

The samples

I wanted more than a report on one jar of fat. I wanted context.

Carrell Farms water buffalo tallow

This sample came from water buffalo raised here at Carrell Farms. It was gently dry-rendered at a low temperature using the same approach we use for the tallow in Buffalo Gal skincare.

This is the material I know most intimately—from pasture, to animal, to rendered fat, to finished formula.

Grassfed beef tallow

The comparison beef sample was a composite of 100% grassfed tallows from several farms I know and trust.

Each farm had already rendered its own tallow using a low-and-slow dry method. I did not render these samples myself, but they represented thoughtfully raised and carefully handled grassfed beef tallow—not an anonymous industrial ingredient.

Five-times salt-water-refined beef tallow

The third sample came from a skincare maker who promoted tallow as being high in vitamins. She reported refining her tallow five times with salt water.

I submitted that sample because I wanted to know whether the vitamin claim could be measured—not because one sample can settle every question about refining.

That distinction matters.

These reports compare individual submitted samples. They are not a controlled study of every water buffalo, every cow or every rendering method.

The finding that stopped me in my tracks

The January 2023 water buffalo and grassfed beef samples were received by the same laboratory on the same day and analyzed using the same fatty-acid method.

Their profiles were not identical. They were not even particularly close in several places.

The most visually dramatic differences were the higher stearic-acid measurement and the unexpected 5.15% C16:3 result in the buffalo sample.

But dramatic does not automatically mean beneficial.

About stearic acid

Stearic acid is a long-chain saturated fatty acid familiar to cosmetic formulators. It can influence the firmness, structure, glide and protective feel of a balm.

The unusually high percentage in our buffalo sample helps explain why this tallow behaves differently on my formulation table. It is part of the material’s character.

What the report does not establish is that a higher percentage will produce a particular result in human skin. That depends on the complete formula, how the fatty acids are carried, the amounts used and the individual wearing it.

About C16:3

C16:3—hexadecatrienoic acid—was the surprise.

The laboratory measured it at 5.15% in our buffalo sample and below 0.02% in the comparison beef sample.

That makes it an unusual compositional finding worthy of further investigation. It does not give me permission to invent a skincare benefit for it.

I have not found direct human topical research showing what this particular C16:3 measurement means for aging skin. Until better evidence exists, I will treat it as an intriguing field note—not a promise.

There is a great deal of “we don’t know yet” in honest science. I’m comfortable with that.

About those vitamins

This is where my understanding changed most.

In the Carrell Farms buffalo sample, the laboratory measured:

• Vitamin E, reported as alpha-tocopherol: 2.41 mg/100 g
• Vitamin A, reported as retinol: 205 IU/100 g
• Vitamin K1: 0.16 µg/g
• Vitamin K2 as MK-4: 0.06 µg/g
• Vitamin D: below the laboratory’s reporting limit

These are real measurements from this sample.

They are not evidence that tallow is “packed with” vitamins.

The five-times-refined beef sample was tested and then reported again using lower detection or quantification thresholds. The vitamin results remained non-detect or below the applicable reporting limits. That particular sample did not substantiate a high-in-vitamins claim.

A later dry-rendered grassfed beef sample contained measurable—but modest—amounts of vitamin A, K1 and MK-4. Its vitamin E and D results were below the reporting limits used for that test.

Taken together, these reports taught me not to make broad declarations about what every grassfed tallow contains.

Species may matter. The individual animal may matter. Diet, season, body-fat location, handling, rendering and refinement may matter, too. Testing methods and reporting limits matter.

And one sample cannot tell us which factor produced each difference.

If a vitamin claim matters, it should be tested rather than repeated.

What does this mean for aging skin?

As skin ages, its lipid story changes.

Human research has found age-related reductions in major stratum-corneum lipids, including ceramides. Other research has shown that appropriately formulated mixtures of physiological lipids can support barrier recovery in aged skin—but that the types and ratios of those lipids matter.

This is important context, but it does not mean that the fatty acids in a jar of tallow are identical to the organized ceramides, cholesterol and free fatty acids in the skin barrier.

They are not.

The laboratory reported most of the fat in our buffalo sample as triglycerides. A fatty-acid analysis tells us which fatty acids were present within that material. It does not show that those fatty acids will automatically enter the skin, reorganize its barrier or create a clinical result.

So why does the profile matter to me as a formulator?

Because ingredients are not interchangeable simply because they share a familiar name.

The fatty-acid composition of a tallow influences its texture, melting behavior, stability and how it behaves alongside the other ingredients in a finished formula. Understanding the raw material helps me formulate with greater intention.

For aging skin, the goal is not to chase one heroic molecule.

It is to create thoughtful formulas that help skin feel more comfortable, supple, cushioned and supported—without pretending that a cosmetic can turn back time.

What these reports cannot tell us

These tests are valuable, but their limits deserve as much attention as their findings.

They do not prove that:

• Every water buffalo tallow will share this profile.
• Every beef tallow will resemble the samples tested here.
• Dry rendering caused the differences between the buffalo and beef samples.
• Salt-water refining removed the vitamins from the refined sample.
• C16:3 provides a particular topical benefit.
• A high stearic-acid percentage makes every formula better.
• Raw tallow and the human skin barrier are compositionally identical.
• A Buffalo Gal product will repair, treat or medically alter aging skin.

To determine what processing alone changes, we would need matched portions of the same original tallow tested before and after controlled rendering or refinement.

That is a future question worth pursuing.

For now, the responsible conclusion is that the submitted samples were compositionally different—and that familiar claims about tallow should not be treated as universal facts.

Why I’m showing you

I could have looked at the small amounts of vitamins in our buffalo sample, rounded the story upward and joined the chorus.

That would have been easier.

But you deserve to know the difference between a measured result and a marketing interpretation.

The reports did not make me less interested in tallow. They made me more interested in it.

They led me away from borrowed claims and toward better questions:

What is actually in this fat?
How was it raised?
How was it rendered?
How does it behave in a complete formula?
And what can I responsibly say about the skin it is intended to support?

I still raise the animals, render the tallow, study the reports and ask an unreasonable number of questions.

These are some of the answers.

There will be more questions.

The laboratory reports

The complete reports will be made available here with personal address information removed. No result pages or laboratory qualifications will be omitted.

Laboratory results apply only to the individual samples submitted. Buffalo Gal Grassfed Beauty did not commission a controlled clinical study, and these compositional reports do not establish medical or therapeutic outcomes.

Research notes

Skin-aging context: Rogers J, et al. “Stratum corneum lipids: the effect of ageing and the seasons,” Archives of Dermatological Research (1996). View study.

Barrier-recovery context: Zettersten EM, et al. “Optimal ratios of topical stratum corneum lipids improve barrier recovery in chronologically aged skin,” Journal of the American Academy of Dermatology (1997). View study.