It can be frustrating when erectile dysfunction (ED) medications like Megalis (Tadalafil) become less effective over time, especially with underlying hypothyroidism. Hypothyroidism itself can contribute to ED by affecting hormone levels and blood flow.

• Since you are on Thyronorm (levothyroxine) for hypothyroidism, it’s important to ensure your thyroid levels are well-controlled with regular thyroid function tests, as inadequate thyroid hormone replacement can worsen ED.
• Tadalafil (Megalis) effectiveness can decrease due to tolerance or other health factors; discuss with your urologist or endocrinologist about adjusting the dose or trying alternative treatments.
• Lifestyle factors such as managing stress, avoiding alcohol, quitting smoking, and maintaining a healthy weight can also improve erectile function.
• Some supplements like L-arginine, zinc, or multivitamins may support sexual health, but these should be used under medical advice.
• If you experience any side effects or have heart conditions, inform your doctor before changing medication.

Please consult a urologist or endocrinologist for a thorough evaluation and personalized treatment plan to address both your hypothyroidism and erectile dysfunction effectively. If you want, I can explain more about how thyroid health affects sexual function.To narrow down potential causes, we will need some more information.Please tell me your age and gender.