What Red Bull Zero Does to Your Blood Glucose Level (CGM Test)

How does Red Bull Sugar Free affect your blood sugar? I tested it using a CGM, and the results were surprising. The can is labeled as having zero sugar and zero carbs, so I expected little to no glucose change. But after drinking it, my blood glucose went from 4.8 mmol/L (86 mg/dL) to 5.7 mmol/L (103 mg/dL)—a 24% spike. While it stayed under the clinical threshold of concern, it’s still a noticeable rise for a “zero” drink. If you’re caffeine- or sweetener-sensitive, this might be worth keeping an eye on.

Metabolic Health Insights 🔬

This experiment underscores that even sugar-free, zero-carb drinks like Red Bull Zero can influence blood glucose levels. Although the label says “0 sugar,” ingredients like caffeine and artificial sweeteners (e.g., aspartame, sucralose) may still impact glucose metabolism and insulin response in sensitive individuals. The postprandial glucose rise of 1.1 mmol/L (17 mg/dL) suggests a mild endocrine reaction—possibly triggered by cortisol elevation from caffeine. For people managing insulin resistance, aiming for glucose stability, or preventing type 2 diabetes, understanding these nuances is key. Continuous glucose monitoring helps decode how “invisible” factors affect your metabolic health.