Bioinspiration is a powerful approach when designing functional biomaterials. Synthetic bone substitutes have been used for more than 40 years in the clinics. However, after decades of research, they have not been able to outperform autografts, which are still the gold standard. Recently, novel biomimetic routes have opened unprecedented possibilities in terms of tuning the nanostructure and composition of hydroxyapatite, imitating more closely the mineral phase of bone. Moreover, tuning the size, shape and composition of hydroxyapatite nanocrystals has proven to be an efficient way to promote the osteoinductive and osteogenic properties of the material.