To explore this hypothesis, this study aims to determine the effects of insulin sensitization using Metformin as an adjuvant to a fixed dose GH therapy for 6 months in short SGA children. The patients will be short SGA children between age 4 -10 years and identified from three paediatric endocrine units in Denmark, Ireland and the United Kingdom. In this mechanistic study 24 subjects starting GH treatment will be randomised in a 1:1 ratio to adjunctive Metformin or placebo for 6 months and followed-up for another 6months. The participants will receive GH treatment for the entire duration of the study (12 months) and will undergo an oral glucose tolerance test and dual-energy x-ray absorptiometry scan to determine glucose metabolism and body fat mass respectively at baseline and 6 months, and will have 3 monthly measurements of height, weight and skinfold thickness. The primary outcome will be the area under the curve of IGF-1 levels measured at 0, 1, 3 and 6 months. Secondary outcomes will include changes in insulin sensitivity, height, body fat mass and safety measures at 6 and 12 months.