Do you take butter in your morning brew? It’s not as crazy as it sounds. Bulletproof Coffee—which involves blending grass-fed butter and medium chain triglyceride (MCT) oil into your java—is soaring in popularity.

Based on an ancient Tibetan tea recipe, the drink brand was started by Silicon Valley entrepreneur Dave Asprey, who claims the concoction helped him raise his IQ and lose 100 pounds. Although Asprey’s results are extreme, science has shown that high-quality fats can have brain-boosting effects.

MCT oil, specifically, has been linked to improved brain function and is even being used in drugs for Alzheimer’s disease. Tessa Orrell, a holistic nutritionist in Brooklyn, New York, is a fan of Bulletproof and recommends it to her clients.

“The increased energy and awareness I get from it is pretty remarkable,” she says.

To make your own, blend 1 cup of brewed coffee with 1 Tablespoon MCT or coconut oil and 1 Tablespoon of unsalted, organic, grass-fed butter. Orrell suggests starting with smaller amounts of the oil and butter and working up to the full amount.