The Controversial Kirkland Protein-Shake Ingredient Shoppers Aren't Happy With

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Costco shoppers love a good deal. The Kirkland Signature Protein Shake (with 30 grams of protein) has been spotted at a few stores in Canada. The Kirkland Signature Protein Shake (with 30 grams of protein) has been spotted at a few stores in Canada, though it's rumored on TikTok that this drink will be available in the U.S. as well. But after these shakes joined Kirkland's high-protein offerings at some stores social media has been flooded with negative reactions. The reason's at the back of the bottle. The third listed ingredient is canola oil and folks aren't happy.

"You lost me at Canola Motor Oil," one Instagram user declared. The sentiment echoed across Reddit threads and TikTok videos where the ingredient list overshadowed the competitive $1.66-per-bottle price point. Another commenter was more succinct: "I was intrigued until I saw canola oil." The controversy spread fast enough that warnings are starting to make rounds on the Internet, with influencers and other buyers urging people to avoid these Kirkland shakes.

All protein shakes have a touch of cooking oil added to give them a thicker, more drinkable texture. The cooking oil also bolsters the calorie count of the drink and gives you some extra fat. Different brands choose different types of oil – Premier, for instance, uses soybean and sunflower oil, while OWYN shakes use a blend of sunflower and safflower oil for the job. Kirkland's latest shake has canola oil, and while it's become one of the most popular cooking oils  since it was formulated by Canadian scientists in the '70s, it's rather disliked among health buffs as it's believed to be a cheap, unhealthy type of oil since it's highly refined and is made primarily from GMO crops.

The canola (rapeseed) oil debate is decades old and intensely divisive. One side presents peer-reviewed evidence — like this 2023 Nutrients journal study highlighting heart health benefits, anti-inflammatory properties, antimicrobial effects, even potential cancer protection. The other side counters with research like a 2011 study from Lipids in Health and Disease suggesting the exact opposite: Decreased longevity instead of increased wellness.

Many critics also fixate on hexane, a chemical solvent used during oil extraction. While it is toxic, the chemical evaporates during processing, leaving nothing behind in the final product. The omega-6 fatty acid content also draws fire, with claims that it triggers inflammation throughout the body, except that studies have repeatedly demonstrated that canola oil consumption doesn't increase inflammation. While the final say on whether canola oil's good for us or not is still a work-in-progress, Harvard's School of Public Health states plainly that there's very little reason for concern. Canola oil also gets a thumbs-up from the American Heart Association since it's low in saturated fat content and contains alpha-linolenic acid, a plant-based omega-3 that supports heart health.

The real issues with canola oil tend to emerge when it's repeatedly reheated in restaurant deep fryers — not when consumed in small amounts in a ready-to-drink protein shake. So if you love protein shakes, feel free to snap them up when you find them.