There are currently no supplements that have been proven to directly turn white fat into brown. However, there are a few lifestyle changes and natural ingredients that may promote the formation of new brown fat cells or help to increase the activity of existing ones.
Some research suggests that regular exercise can help to convert white fat into brown, as it encourages the body to use more energy and results in an increased production of heat. This process is known as browning and is thought to be beneficial for overall health.
Certain dietary compounds, such as polyphenols found in green tea, resveratrol from grapes and ellagitannins present in pomegranates, have also been shown to stimulate browning in animal studies. It's not clear yet if these same effects would occur in humans, but eating foods rich in these antioxidants may still be beneficial for overall health.
Finally, exposure to colder temperatures has also been shown to promote browning, likely due to the fact that it forces the body to burn more energy (and generate more heat) in order to maintain a normal body temperature. So spending time outdoors in cooler weather or taking regular cold showers may help encourage the formation of new brown fat cells.