Stellar masses are crucial ingredients for putting galaxies in the context of galaxy evolution and are commonly evaluated via Spectral Energy Distribution (SED)-fitting analyses which are hampered by dust attenuation. Observational constraints of attenuation in various galaxy classes provide key inputs for fitting a SED. I will present recent results about the attenuation properties of a sample of Herschel-selected galaxies at 0.7 ⩽ z ⩽ 1.6 widely spanning the star-forming Main Sequence (MS). I will show that far-IR selected galaxies on the MS are well described with local attenuation recipes. Conversely, common recipes cannot recover the SFR of far-IR selected starburst galaxies well above the MS. The SFR of these outliers appears to be hidden by the ∼90% in optically thick cores. These findings pose challenges for SED-fitting codes based on energy balance assumptions that might break in these peculiar sources.