Curb® weight-loss aid: An overview of evidence

Curb is a unique food supplement containing the herbal combination YGD (Yerba Mate, Guarana, and Damiana) which is scientifically and clinically proven to be effective for:

  • Weight loss

  • Weight management over a long period

  • Modulating the levels of hormones which control eating behaviour

  • Eating less at meals

  • Snacking less between meals

  • Making healthier food choices

This extensive evidence was gained in a total of 10 independent studies on the YGD formulation in Curb by leading researchers and published in peer-reviewed journals. 

Curb may be taken continuously at a full dose of up to three capsules per day. over a period of time or it may be taken occasionally to control eating on particular days.

YGD Research Evidence

Initial weight loss and mechanistic study

The initial key study was undertaken by two Danish medics, Dr Andersen and Dr Fogh.

In the study, 47 overweight subjects took either a YGD capsule or a placebo (dummy tablet) for 45 days. Those taking YGD lost an average of 5.1 kg (11.2 lbs) whereas those taking placebo lost just 0.3 kg (0.7 lb).

23 subjects who had lost weight with YGD were studied for a further 12 months and instructed to take YGD again if they gained more than 1 kg. The group had almost the same average weight (72.5 kg) at the end of the 12 months as at the start (73kg).

Ultrasound studies also demonstrated that YGD slowed the rate at which the stomach emptied, thus explaining the ‘feel full sooner’ effect. Their results were published in the Journal of Food Nutrition and Dietetics.

Studies lead by Dr Carrie Ruxton.

Dr Carrie Ruxton is a leading dietician and health journalist. She has led three studies into YGD products. The most extensive study, published in the British Food Journal, was undertaken in conjunction with researchers at University of Leeds and involved 73 overweight healthcare professionals who took YGD for six weeks. 

The findings (average at six weeks) were:

  • Weight loss of 2.3kg (5 pounds) 
  • Waist reduction 3.4 cm 
  • Hip reduction of 3.7cm
  • Increased post meal fullness rating
  • Reduced between meal hunger ratings
  • Reduced tendency to snack


University of Liverpool Research

Further research was undertaken by a team led by Professor Jason Halford of University of Liverpool; a leading authority on appetite and obesity and Director of the Human Ingestive Behaviour Laboratory. 

In a carefully controlled study, they measured food intake at an ad libitum lunch following a set calorie breakfast. YGD or a placebo was taken 15 minutes before breakfast and lunch.

Their findings after taking YGD were compared to controls and published in the journal Appetite were as follows:

  • Lower food and calorie intake: A reduction in food (59.5g) and energy (112g) intake at lunch after taking YGD

  • Healthier food choices:  A significant reduction in energy intake from high-fat sweet items at lunch after taking YGD.

In addition, they studied the combined effect of YGD with the dietary fibre, inulin.

Inulin increased the effect of YGD on food intake. When taken together, there was a statistically significant effect on decreased hunger and desire to eat.

These findings show that YGD produces a robust effect on reducing calorie intake at a meal and very interestingly, they also demonstrate that YGD leads to healthier food choices.

Research led by Dr Marcelo Lima Ribeira in Brazil

Dr Ribeira researched the physiological effects of Yerba Mate extracts and Guarana extracts with a focus on obesity and  included YGD into his research.

He led a large team from three Brazilian Universities and studied how YGD impacted food intake and blood levels of the eating hormones, acetylated ghrelin and GLP-1, in 20 overweight women. Both hormones are released in the gut and act on the brain. Ghrelin (also called the hunger hormone) promotes hunger and stimulates food intake. GLP-1, in contrast, promotes satiety and delays gastric emptying and prolongs the feeling of satisfaction.

The placebo-controlled study was similar in design to that in the Liverpool study. YGD was taken before a set breakfast and again before an ad libitum lunch. Energy reduction at lunch was reduced by an average of 43 calories.

Blood samples were taken periodically for hormone analysis. The results showed decreased ghrelin levels and increased GLP-1 levels after taking YGD. The authors concluded that YGD reduced food energy intake by modulating the gut hormones in overweight women.

Review on the positive effects of Yerba Maté on obesity

Dr Ribeiro also reviewed the many studies, mainly in animals, involving Yerba Maté and obesity. Several published research studies show that Yerba Maté itself caused weight loss in overweight animals. 

Research has also shown that Yerba Maté extracts inhibit adipogenesis, the formation of new fat cells, in mice and demonstrated that YGD had a similar effect. Yerba Maté extracts were also shown to modulated gene expression in the obese state and return gene expression to more normal levels.


  1. Andersen, T and Fogh, J (2001). ‘Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patients’, Journal of Human Nutrition and Dietetics, Vol. 14, pp. 243-250.
  2. Ruxton, C. H. S., Kirkwood, L., McMillan, B., StJohn, D., and Evens, C. E. L., (2007), Effectiveness of a herbal supplement for weight management’, British Food Journal, Vol. 109, pp. 416-428.
  3. Harrold, J. A., Hughes, G. M., O’Sheil K., Quinn, E., Boyland, N.J., Williams, N.J., and Halford J.C.G., (2013). Appetite, Vol 62, 84- 90.
  4. Calestino, M.M. et al (2017). Journal of Functional Foods, Vol 35 555-563
  5. Gambero, A and Ribeiro M.L. (2015). The Positive Effects of Yerba Maté (Ilex paraguariensis) in Obesity. Nutrients, Vol7 730 – 750 
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