What's Really In Starbucks' Protein-Boosted Milk?

It's always a big deal when Starbucks releases a new menu item, and its most recent release is more than just a new flavor. On September 29, 2025, Starbucks launched a new range of Protein Lattes and Cold Foam Drinks. The protein-enhanced drinks contain up to 36 grams of protein in a grande-sized cup (16 ounces), while the cold foam contains 15 grams of protein. What's interesting is that you can ask for the protein-boosted milk and/or the foam to be added to almost any beverage, Starbucks has confirmed, so you likely won't have to change your regular order that much to get some extra protein in your beverage. We found Starbucks' protein drinks to be a delicious way to get your protein in, but, like many other customers, we couldn't help but wonder where the extra protein comes from.

Starbucks has revealed that its protein-boosted milk is made with whey isolate. This is different from the regular whey found in many protein shakes and bars. Whey isolate is a processed version of this which contains less fat and lactose. It comes from cow's milk and is a great source of protein due to its ability to provide amino acids that your body cannot synthesize. Starbucks opted to use it specifically for its nutrition, taste, and texture, which it claims does not change the flavor or consistency of the drink. The protein-boosted milk can be used in a latte or a matcha (both iced and regular), and the protein cold foam comes in a variety of flavors, including banana, vanilla, chocolate, salted caramel, and brown sugar. There are also seasonal flavors, such as pumpkin and pecan.

Starbucks customers have mixed feelings regarding the protein drinks, with some disagreement about whether they actually taste good. Protein powder isn't exactly known for its great flavor, but whey protein is typically deemed the best-tasting option out there. Some customers have complained that the protein gives the coffee a thick texture and bad flavor, while others have said Starbucks was truthful about the whey protein having no effect on the flavor, claiming that the consistency is smooth and nowhere near chalky. Supporters of the new items say that since the coffees are already flavored, any protein powder taste gets overpowered.

Of course, the added protein comes with a higher price: $1 for the boosted milk and $2 for protein cold foam. It's already not the cheapest coffee out there (though we know of a great hack for ordering a cheaper Starbucks latte), so whether or not you opt for the boosted milk or foam will likely depend on how desperate you are to get some extra protein on the day. Overall, this is a highly convenient way to hit your protein goals. But are the protein drinks here to stay? Some people online have predicted that they will vanish once the hype dies down, and it's hard to blame them — after all, Starbucks has been known to suddenly discontinue drinks. However, that likely won't be the case here, as the protein drinks were announced as a permanent part of the menu.