Over the years the paradigm of treating early during the migraine attack has become well established in clinical practice. It is also recommended that the 5-HT1B/1D agonists be administered early during the migraine attack for efficacy. This is because it has been proposed that most migraineurs are less responsive to delayed treatment, owing to the development of central sensitization of the pain transmission. The main objective of this prospective, cross-over study at a specialist clinic was to evaluate if these recommendations should also apply to the subcutaneous formulation of sumatriptan. Results are based on 20 adult International Headache Society migraineurs. Two attacks (n = 40) were treated with 6 mg subcutaneous sumatriptan as early as possible after the onset of migraine headache and two attacks (n = 40) as late as the patients could bear. The median intra-individual difference between the two strategies in time from first occurrence of pain to injection was 5.7 h and the median intra-individual difference in pain intensity at the time of injection was 29 visual analogue units. No significant differences were found in time to freedom from pain, pain severity at 1 and 2 h, area under the curves from injection to pain free or in headache recurrence after injection. At the end of the study, most of the patients claimed that their medication was as effective when given early as when given late in the course of the attack. The discrepancy between our present findings and retrospective analyses of trials on oral triptans probably has more to do with the less disturbed pharmacokinetics early during the migraine attack than with central sensitization. Consequently, we recommend nonoral formulations of triptans, which do not necessarily have to be administered early during the migraine attack to provide efficacy. In conclusion, it is reassuring for migraineurs that it is worthwhile taking their medication in an appropriate formulation even if they have not been able to do so early in the course of the attack.