Data suggest that supplementation of growing animals with capsicum oleoresin or with SUCRAM (Suc) improves growth efficiency; however, responses to the 2 additives fed in combination have not been described. The objective of this study was to investigate the effects of a blend of rumen-protected capsicum oleoresin (RPC) and Suc on the growth performance, blood chemistry and cell counts, markers of fat mobilization, and hormones in growing lambs. Thirty-six lambs (Dorset and Suffolk × Hampshire) were used in a 7-wk randomized complete block design experiment. Lambs were housed in 9 pens (4 lambs/pen) and pens were blocked based on lambs’ average body weight (47.4 kg; SD = 2.62). Pens within a block were randomly assigned to one of the following treatments (3 pens/treatment): (1) control (no additive), (2) 86 mg/head/d RPCSuc (RPCSucL; Pancosma, Switzerland), and (3) 171 mg/head/d of RPCSuc (RPCSucH). CapsSuc was mixed with the concentrate portion of the diet; hay was offered ad libitum. Body weight of the lambs was recorded weekly and blood samples were collected from the jugular vein once, 2 h after feeding, at the end of the experiment. Average daily gain was not affected by treatment (P ≥ 0.22; 238 g/d; SEM = 12.1). RPCSuc tended to linearly decrease (P = 0.06) dry matter intake (1.60, 1.60 and 1.52 kg/d for control, RPCSucL, and RPCSucH, respectively; SEM = 0.021) and therefore tended to linearly decrease (P = 0.10) feed:gain (7.07, 6.77 and 6.22 kg/kg for control, RPCSucL, and RPCSucH, respectively; SEM = 0.294). Treatment had no effects (P ≥ 0.22) on blood cell counts and concentrations of nonesterified fatty acids, β-hydroxybutyrate, and glucose. Blood serum insulin concentration was quadratically decreased (P < 0.01) by RPCSuc. RPCSuc tended to quadratically increase (P = 0.06) cortisol and had no effect on haptoglobin concentration in blood serum. In this experiment, dietary supplementation of a blend of artificial sweetener and capsicum had a modest effect on productive performance of lambs, and it appeared to have a regulatory effect on insulin secretion.