Researchers tested a natural supplement made from a plant called Cyperus rotundus to see if it could help people lose weight. In a 90-day study with 96 obese adults, half took the supplement while the other half took a fake pill. Both groups also followed an exercise and diet plan. The people taking the real supplement lost more weight, had smaller waist measurements, and showed better cholesterol levels than those taking the fake pill. No one experienced harmful side effects. This suggests the supplement could be a safe, natural option to help with weight loss when combined with healthy eating and exercise.

The Quick Take

  • What they studied: Does a natural plant extract supplement help people lose weight and improve their health when combined with diet and exercise?
  • Who participated: 96 adults with obesity participated. The study lasted 90 days, with half receiving the supplement and half receiving a placebo (fake pill). Everyone followed the same exercise and diet plan.
  • Key finding: People taking the supplement lost more weight and had bigger reductions in waist size compared to those taking the placebo. They also had healthier cholesterol levels. The supplement appeared safe with no reported side effects.
  • What it means for you: This supplement may help boost weight loss results when you’re already eating healthy and exercising. However, it’s not a replacement for diet and exercise—it works alongside them. Talk to your doctor before starting any new supplement.

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of scientific studies. Researchers divided 96 obese adults into two groups randomly. One group received 500 mg of Cyperus rotundus extract combined with 5 mg of piperine (a substance that helps the body absorb the extract better) twice daily. The other group received a placebo—a pill that looked identical but contained no active ingredients. Neither the participants nor the researchers knew who was getting the real supplement, which is called “double-blind” and helps prevent bias. Everyone followed the same prescribed diet and exercise program for 90 days. The researchers measured body weight, waist size, hip size, and blood cholesterol levels at the start and end of the study.

This study design is important because it controls for the placebo effect—the improvement people experience just from believing they’re getting treatment. By comparing the supplement group to a placebo group, researchers can determine if the supplement itself actually works. The double-blind design ensures neither participants nor researchers unconsciously influenced the results.

This is a well-designed study with several strengths: it’s randomized (reducing bias), double-blind (preventing expectation effects), and includes a placebo control group (the gold standard for comparison). The study lasted 90 days, which is long enough to see meaningful changes. However, the sample size of 96 people is moderate—larger studies would provide stronger evidence. The study was published in Medicine journal in 2025, indicating recent research.

What the Results Show

The supplement group experienced significantly greater weight loss compared to the placebo group. Body mass index (BMI), a measure of body weight relative to height, decreased more in the supplement group. Waist circumference and hip circumference both showed greater reductions in the supplement group, suggesting the supplement particularly helped reduce belly fat. These measurements are important because excess belly fat is linked to health problems like heart disease and diabetes. The improvements were observed while both groups followed the same diet and exercise plan, suggesting the supplement provided additional benefits beyond lifestyle changes alone.

Beyond weight loss, the supplement group showed improved cholesterol levels and better Apolipoprotein B-100 levels (a marker of heart disease risk). These improvements in blood lipid profiles are significant because they suggest the supplement may help protect heart health, not just reduce weight. The study found no adverse events or safety concerns in either group, and all blood test results remained in normal ranges, indicating the supplement was well-tolerated.

Earlier laboratory studies showed this plant extract could reduce fat cell formation in test tubes and animal models. This human study confirms those promising early findings work in real people. The addition of piperine (a black pepper compound) was designed to improve absorption, making the supplement more effective than the plant extract alone would be. This builds on previous research showing piperine enhances nutrient absorption.

While this study is well-designed, it has some limitations. The 90-day timeframe shows short-term results, but we don’t know if benefits continue long-term or if people maintain weight loss after stopping the supplement. The study included only obese adults, so results may not apply to people of normal weight or those with different health conditions. The sample size of 96 is moderate; larger studies would provide stronger evidence. We don’t know how the supplement compares to prescription weight-loss medications. Additionally, all participants followed a diet and exercise program, so we can’t determine if the supplement works without lifestyle changes.

The Bottom Line

Based on this research, the Cyperus rotundus extract with piperine appears to be a safe supplement that may help with weight loss when combined with healthy eating and regular exercise. However, this is one study, and more research is needed before making strong recommendations. If you’re interested in trying this supplement, discuss it with your doctor first, especially if you take medications or have health conditions. Remember: no supplement replaces the importance of a healthy diet and regular physical activity. Moderate confidence in these findings—they’re promising but need confirmation from additional studies.

This research is most relevant to adults with obesity who are already committed to diet and exercise changes and want additional support. It may also interest people looking for natural alternatives to prescription weight-loss medications. This research is NOT a substitute for medical advice for people with serious health conditions, those taking multiple medications, or pregnant/nursing women. People of normal weight shouldn’t use this supplement for weight loss.

In this study, meaningful changes appeared over 90 days (about 3 months). You shouldn’t expect overnight results. Realistic expectations: if this supplement works for you, you might notice changes in weight and measurements within 4-12 weeks when combined with diet and exercise. Results vary between individuals.

Want to Apply This Research?

  • Track daily supplement intake (yes/no), waist circumference weekly, and weight weekly. Also log exercise minutes and rate diet adherence daily (1-10 scale) to see how the supplement works alongside lifestyle changes.
  • Set a reminder to take the supplement twice daily with meals. Pair supplement-taking with an existing habit (like breakfast and dinner) to build consistency. Log it immediately after taking it to maintain accountability.
  • Measure waist circumference weekly at the same time of day and location. Weigh yourself weekly (same time, same conditions). Take progress photos monthly. Track energy levels and appetite changes daily. After 12 weeks, review trends to determine if the supplement is working for you personally.

This research summary is for educational purposes only and should not replace professional medical advice. While this study suggests the Cyperus rotundus extract supplement may be safe and effective for weight loss, individual results vary. Before starting any new supplement, especially if you have obesity, take medications, have heart disease, diabetes, or other health conditions, or are pregnant or nursing, consult your doctor or registered dietitian. Supplements are not regulated the same way as medications. This supplement should be used alongside, not instead of, a healthy diet and regular exercise. If you experience any adverse effects, stop use and contact your healthcare provider immediately.