Presumed ETTH patients will be screened at pre-selected primary care settings (general practitioners), and the diagnosis of TTH reviewed (time -30, or T-30) by a neurologist that will ask patients to complete the headache diary for 30 days before randomization. Diaries will be reviewed at time 0 (T0; baseline) by a blind-rater D.O. that will decide if the number of attacks is compatible with the diagnosis of ETTH, allowing randomization. The blind-rater will perform an osteopathic structural examination that will compulsory include (semi-structured evaluation) also the assessment of temporo-mandibular joint disorders and cervical dysfunctions (TMJD and CD) in order to define putative goals of OMT that will be used for scoring a Goal Attainment Scale (GAS, see below Outcomes) without involving the treating D.O. that will operate independently. Furthermore, patients will be asked to complete the Headache Disability Inventory (HDI) and the Headache Impact Test-6 (HIT-6).