The therapeutic potential of oestrogens in obesity and type 2 diabetes is limited by their gynaecological and tumour-promoting actions. To overcome this, Finan et al. designed a conjugate of oestrogen and the antidiabetic hormone glucagon-like peptide 1 (GLP1) to selectively deliver oestrogen to specific tissues. The synergistic action of the conjugate on metabolic parameters and body weight reduction in mice depended on its activity at both GLP1 and oestrogen receptors. Moreover, the conjugate did not have the adverse effects associated with systemic oestrogen actions. The authors suggest that such combinations of peptides and small molecules could offer promise for other diseases.