Rationale, aims and objectives: The aim of the intervention study was to test the feasibility and acceptability of a time consuming and demanding lifestyle-based treatment program in women with levothyroxine-treated primary hypothyrodism with residual symptoms. In addition, the influence of the intervention on participants’ health-related quality of life was assessed. Methods: 14 participants were recruited through an online questionnaire of symptom burden and health related quality of life in patients with levothyroxine-treated primary hypothyroidism. The intervention consisted of three parts: 1) diet including dietary supplements; 2) stress and sleep management; 3) physical exercise. Participants were interviewed at the end of intervention, and 6 and 12 months after intervention. Follow-up questionnaire assessements of health related quality of life (WHODAS 2.0) were made at 6, 12, 18 and 24 months after start of intervention. Results: A very low drop-out rate – 1 in 14 – and a high attendance rate indicate that the intervention program was feasible. Compliance was high, particularly regarding dietary changes and dietary supplement intake. Health-related quality of life improved; the WHODAS score was decreased with 8.5 points after 3 months intervention (p=0.004), 8.8 points at end of treatment (p=0.008) and 7.3 points at 12 months after the treatment ended (p=0.040, mixed effect regression analysis), while no significant change was seen 6 months after treatment (4.1 points, p=0.17). Conclusion: The intervention program was feasible and well accepted by the participants, who reported improvements in health-related quality of life after treatment. The efficacy of such program should be evaluated in future randomized controlled studies.