Liraglutide (LIRA) treatment is associated with the dose-dependent reduction of 
weight. Higher doses are more effective than lower doses, although higher doses 
are also more poorly tolerated. Metformin may enhance the weight-lowering 
potential of LIRA via the stimulatory modulation of incretin in addition to its 
direct beneficial effects in PCOS. The aim of the present study was to evaluate 
whether metformin as an adjunct to low-dose LIRA affects body weight with 
increased efficacy compared with low-dose LIRA alone in obese patients with 
PCOS. In a 12-week study, 44 obese women with PCOS were randomly offered either 
combined treatment (COMBO) with 1,000 mg metformin twice a day and 1.2 mg LIRA 
once a day, or treatment with 1.2 mg LIRA alone. The primary outcome of 
treatment was an alteration in the levels of obesity. A total of 43 patients 
[aged 30.3±4.4 years; body mass index (BMI) 37.2±4.5 kg/m2; mean ± standard 
deviation] completed the study. The subjects treated with COMBO lost on average 
6.2±2.4 kg compared with a 3.8±3.5 kg weight loss in the patients treated with 
LIRA alone (P=0.024). The BMI decreased by 2.2±0.8 kg/m2 in patients treated 
with COMBO and by 1.4±1.2 kg/m2 in patients treated with LIRA alone (P=0.024). A 
clinically significant ≥5% weight reduction was achieved in 59.1% of patients 
treated with COMBO and 42.9% of patients treated with LIRA alone. Reductions in 
glucose levels following oral glucose tolerance testing, as well as in 
androstenedione levels in the COMBO group were significantly greater compared 
with those in the LIRA group. The side effects were mild and transient in the 
two treatment groups. A combination of metformin and low-dose LIRA was more 
effective than low-dose LIRA alone in reducing body weight in obese patients 
with PCOS.