It is true that certain medications may interact with grapefruit or grapefruit juice, but Synthroid is not typically one of them. However, it is generally recommended to take Synthroid in the morning on an empty stomach to avoid interactions with food, particularly dairy products (calcium) and iron, which could reduce the absorption of the medication in your body. If you are unsure about the recommended timing for your situation, you can consult with your pharmacist. Ultimately, the most important thing is to take your tablet consistently, either with a meal containing similar ingredients or on an empty stomach, at the same time each day.