In a world increasingly attuned to sustainability and food innovation, coffee oil—pressed from the beans or salvaged from spent grounds—has begun to emerge from obscurity. Silky, aromatic, and rich in bioactive compounds, this golden-brown elixir captures not just the essence of roasted coffee, but a trove of functional potential. Yet behind its allure lies a chemical complexity that demands scrutiny.

Among its most intriguing ingredients are the diterpenes cafestol and kahweol —natural defence compounds in Coffea plants that have fascinated scientists for decades. These lipid-soluble molecules, once overlooked as mere flavour carriers, have become focal points of toxicological interest. With effects ranging from cholesterol modulation to potential chemoprotective properties, they defy easy classification. Are they friend or foe?

Our new review in Molecules MDPI presents a thorough re-evaluation of coffee oil's safety as a novel food under EU regulation. While coffee oil itself is not new to human exposure—it’s been in our cups for centuries—its isolated use in concentrated form, whether from green beans or industrial waste streams, raises legitimate questions. How much is too much? What happens when it is consumed outside the buffering context of brewed coffee?

Drawing on human clinical data spanning two decades, we synthesised the known effects of cafestol and kahweol on serum lipids, liver enzymes, and related biomarkers. Our conclusion? Moderate exposure through traditional coffee consumption—even unfiltered—poses minimal risk to healthy adults. However, the story changes with concentrated coffee oil supplements or food applications. In these cases, blood cholesterol and liver function parameters may shift significantly, especially among sensitive populations.