Primary outcome will be the change at T120 in patient-reported headache frequency of at least 30% with respect to the control group (based on the previous pilot study, Rolle et al. 2014). Secondary outcomes will include: (a) any significant reduction over time or with respect to the control group of the average headache intensity based on a scale between 0 (absence of pain) and 5 (worst perceived pain) (considered more sensible with respect to a 0-to-3 scale, see Rolle et al. 2014); (b) any significant reduction over time or with respect to the control group of the over-the-counter medication usage; (c) any significant reduction over time or with respect to the control group of the HDI/HIT-6 scores; (d) any significant reduction over time or with respect to the control group in patient-reported headache frequency. Tertiary outcome will be: any significant reduction over time or with respect to the control group of the blind-rater evaluation of the osteopathic effects of the whole treatment with respect to the attainments he initially proposed. This score will be assessed purely in terms of correction of those osteopathic dysfunctions that were detected at T0, by using the GAS, with a five-point score ranging from: -2 (much less than expected outcome), to -1 (less than expected outcome), to 0 (expected outcome reached), to +1 (greater than expected outcome), to +2 (much greater than expected outcome).