OBJECTIVE Botanical compounds and extracts are widely used as nutritional supplements for the promotion of health or the prevention of disease. An extract of Artemisia dracunculus (PMI 5011) has been shown to improve insulin action, yet the precise mechanism is not known. The aim of this study is to demonstrate that the mechanism by which PMI 5011 and two related Artemisia extracts improve insulin action is associated with a down-regulation of de novo lipogenesis (DNL) in the liver and an increase in DNL in the adipose tissue. METHODS Diet-induced obese 16-wk-old male mice (C57 BL/6 J) were divided into four groups: (control, 5011, Santa, and Scopa) and fed for 30 d with respective extracts incorporated into the diet at 1% (w/w). Deuterium was administered on day 30 for the measurement of DNL in blood, liver, and white adipose tissue. Individual fatty acids and glycerol levels were also measured. RESULTS No statistically significant differences were seen in DNL between the control group and the three botanical treatments. Plasma levels of all four long-chain fatty acids were significantly lower in the three treatment groups. Glycerol in the plasma was lower in the treatment groups compared with the control group; however, this did not reach statistical significance in all cases. Tissue levels of the fatty acids and glycerol did not differ between any of the treatment groups. CONCLUSIONS These results suggest that botanicals may not affect fractional DNL in animals on a high-fat diet. However, there were decreases in long-chain fatty acids and in glycerol coming from the newly synthesized triglycerides in plasma.