Musculoskeletal symptoms in hypothyroidism are often vague and non-specific, but in rare cases, rhabdomyolysis may develop as a serious complication. Here, we report a case of a 25-year-old man with a known history of Hashimoto's thyroiditis who presented with symptoms of rhabdomyolysis complicated by renal impairment secondary to severe overt hypothyroidism in the context of medication non-compliance. He presented with symptoms of generalised myalgia and fatigue. Laboratory investigations were consistent with severe overt hypothyroidism with thyroid-stimulating hormone (TSH) 531.4 mIU/L and free thyroxine (T4) 0.9 pmol/L (0.07 ng/dL). Creatine kinase (CK) levels were elevated at 1052 U/L with associated acute renal impairment, creatinine 129 μmol/L (1.49 mg/dL). Our patient was managed with the recommencement of thyroxine therapy and intravenous hydration. Over the course of hospitalisation, the patient's myalgias gradually improved, with an improvement in CK levels and renal function. Our case highlights the potential consequences of prolonged non-compliance. Clinicians should remain vigilant in monitoring patients' medication adherence and be aware of the possible complications from non-compliance. Early recognition and prompt management of such cases can lead to successful recovery and prevent long-term sequelae.