 Hibiscus tea, also known as roselle or Jamaica, is enjoyed around the world hot or cold for its bright red color and tart cranberry-like flavor. It's the zing in red zinger tea. I talk about its benefits in the chapter on high blood pressure and how not to die, working as well as some leading anti-hypertensive medications in head-to-head tests, or even beating the drugs out. In three hours of drinking hibiscus tea, changes in hundreds of metabolites can be detected in the human bloodstream with creative names like hibiscus acid or hibiscin or hibisitrin. Alterations in human gene expression of the three-hour mark after drinking it suggest a down-regulation of cholesterol synthesis and an improvement in metabolism, but randomized controlled trials failed to consistently find cholesterol-lowering benefits. An interesting side effect popped up, though. Weight loss. In Mexico, hibiscus tea has been traditionally used as a treatment for obesity, sparking lots of research interest. Computer modeling studies have suggested that certain hibiscus compounds might bind to the fat-digesting enzyme lipase, like a lock and key test tube studies, screening a variety of medicinal plants, did indeed find hibiscus-inhibited lipase, more than most of the others. And hibiscus has been found to reduce body fat in hamsters, mice and rats, increasing fecal fat excretion, but it wasn't tested in people until this study published in 2014. The title gives the findings away. Spoiler alert, hibiscus can inhibit obesity and fat accumulation in humans and improve fatty liver. To create a randomized double-blind trial, instead of trying to create some artificially colored and flavored placebo tea, they just dried the hibiscus tea into powder and put it into capsules. After 12 weeks, there was a greater reduction in waistlines and percent body fat in the hibiscus group compared to those who got placebo capsules, but the dose they ended up using was equivalent to like 9 cups of hibiscus tea a day. I recommend people stick to no more than a quarter day on a regular basis due to the high manganese content. Manganese is an essential trace mineral, but 9 cups a day might result in too much of a good thing. Finally, in 2018, this study was published using a reasonable dose, the equivalent of about a single 12-ounce glass of hibiscus tea a day. The complicating factor is that they also added lemon verbena to the mix. That's another herbal tea, better known for improving recovery after intense bouts of strength training. But there was some promising in vitro data on effects of lemon verbena on fat cells in a petri dish, so they tried a combination. It comes out to be about a cup and a half of hibiscus tea and a quarter cup of lemon verbena tea once a day for two months. Both the tea and placebo groups for fed diets contain the same amount of calories, yet those randomized to the tea group lost significantly more weight, 5 pounds, compared to 3 pounds. That's only an extra pound or two a month, but an extra pound a month eating this same number of calories. That's the advantage of fat-blocking interventions that actually cause you to lose more calories beyond just reducing hunger and making you feel fuller longer in hopes you'll eat fewer calories in the first place. Why not just pop pills instead of brewing tea? There's all sorts of herbal extract supplements on the market, but that presumes we know enough to extract out the right active ingredients. For example, it does not appear to be the red anthocyanin pigments in hibiscus since white varieties seem to have similar effects. When the various compounds in hibiscus tea are isolated out and tested in various combinations, synergistic effects are found, meaning the whole may be greater than the sum of its parts. As with any sour food or beverage, though, like after eating citrus, it's important to wash the natural acids off your teeth by rinsing your mouth out with water to protect your tooth enamel. You also want to wait at least an hour before brushing so as not to erode your enamel when it's in a softened state.