Guggul, the sticky gum resin from the mukul myrrh tree, plays a major role in Ayurveda, the traditional herbal medicine of India. Guggulsterones are an extract of the herb, commiphora mukul. Research with laboratory animals suggests guggul may help enhance thyroid function. Guggul may change thyroid hormone metabolism, due to the increased conversion of the inactive thyroid hormone T4 into its active part T3 in the liver, increasing levels of circulating T3, a thyroxine metabolite known to raise overall metabolism. What's more, Guggulsterones may also stimulate the thyroid directly by enhancing TSH (Thyroid Stimulating Hormone) production.