Ayurvedic practitioners also used gugul for weight-loss. It was thought then that the herb acted as a metabolic tonic, but its mechanism of action was unknown. It is now known through research that gugul has an effect on the thyroid gland. In short, gugul raised the levels of circulating thyroid hormones, which may account for its ability to regulate obesity and cholesterol levels. In summary, gugul offers an interesting potential and it is time that we re-examined this wonder of the past.