What Is A2/A2 Dairy and Why Do We Use It?

August 3, 2026 • Boss Cow

For more than a decade, dairy was something I avoided completely. Even a small amount could leave me doubled over in pain and bloated for days. I assumed that was simply how my body reacted to dairy.

Then I tried dairy from A2/A2 cows.

For the first time in years, I could eat real dairy without the same pain and bloating. I wanted to understand why this dairy felt so different, and the more I learned, the more important A2/A2 dairy became to me.

That discovery is a big part of why Kevin and I started Boss Cow. It is also why A2/A2 is the only type of dairy I choose to eat and the only type we use in our products.

So what is A2/A2 dairy, and why can it feel different for some people?

What Is A2/A2 Dairy?

A2/A2 dairy is real cow’s milk. The difference comes down to one of the proteins in the milk, called beta-casein.

Cows can be A1/A1, A1/A2, or A2/A2. Only A2/A2 cows naturally produce milk containing A2 beta-casein without any A1.

It is not determined by breed alone. The genetics of each individual cow matter, so you cannot assume milk is A2-only based on the type of cow. Although A2/A2 cows are more common among traditional heritage breeds like Jerseys, Guernseys, and Brown Swiss, the only way to know for sure whether milk is A2-only is to confirm the genetics of each individual cow.

One thing I found fascinating when I started learning about this is that A2 is considered the original form of beta-casein in cows. The A1 variant appeared later through a genetic mutation and became common in many modern dairy herds, including Holsteins. Most grocery-store milk is not separated according to the cows’ beta-casein genetics, so it can contain both A1 and A2 unless it is specifically sourced from verified A2/A2 cows.

Human milk and milk from goats, sheep, and camels are also often described as having A2-type or A2-like beta-casein. The A1 and A2 labels technically refer to variants of cow’s milk beta-casein, but this helps explain why A2 is often called the original milk protein.

What Is the Difference Between A1 and A2 Milk?

A1 and A2 beta-casein are nearly identical. They differ by only one amino acid, but that small difference can affect how the protein breaks down during digestion.

When A1 beta-casein is digested, it can release a peptide called BCM-7 more readily than A2 beta-casein. Researchers are studying whether this difference may help explain why some people experience bloating, stomach pain, or other digestive discomfort after consuming milk containing A1 protein.

Some human studies have found that participants experienced fewer digestive symptoms after consuming A2-only milk compared with milk containing both A1 and A2. The research is still developing, and A2/A2 dairy will not affect everyone the same way.

For me, the difference was clear. I could eat A2/A2 dairy without the pain and days of bloating I had come to expect from most grocery-store dairy.

Is A2/A2 Dairy Lactose-Free?

No. A2/A2 refers to the protein in milk, not the sugar. A2/A2 dairy still contains lactose unless the lactose is removed through a separate process.

A lot of people assume lactose is the only reason dairy bothers them. I did too. But for some people, the type of milk protein may also be part of the picture.

Some studies have found fewer digestive symptoms with A2-only milk even though it still contained lactose. That does not mean everyone who reacts to dairy is reacting to A1 instead of lactose. It simply means lactose may not be the whole story for everyone.

A2/A2 dairy is still real dairy and contains milk proteins. It is not appropriate for anyone with a cow’s milk allergy. Lactose intolerance and a milk allergy are two different conditions.

Why Does Boss Cow Use Only A2/A2 Dairy?

Because it is the dairy I spent years trying to find, and it is the only type of dairy I choose to eat.

When Kevin and I lived in California, we joined a local co-op and drove two hours each way to pick up A2/A2 dairy from a farm we trusted. We made that drive because of how much better I felt when I ate it.

Every Boss Cow product uses 100% A2/A2 dairy from cows that naturally produce only A2 beta-casein. Never a blend.

Using A2/A2 dairy makes sourcing harder and more expensive, but using anything else would go against one of the main reasons we started Boss Cow.

A2/A2 is also only the starting point. We care about what the cows eat, how they are raised, how farmers care for their land, and whether our sourcing supports family farms instead of anonymous industrial supply chains.

We built Boss Cow to make the kind of food we had spent years trying to find ourselves.

A note on health: This article reflects current research and my personal experience. A2/A2 dairy is not lactose-free and is not a treatment for lactose intolerance or any medical condition. Nothing here is medical advice.

Sam
Co-Founder, Boss Cow