In some cases, mixing medications with over-the-counter products causes adverse reactions. Synthroid is a medication prescribed for low thyroid hormone levels and prevention of goiter. Whey protein, available without a prescription, increases your daily protein intake, ideal for people with a low appetite or an eating disorder. Many bodybuilders and athletes use whey protein to build muscle and endurance. Whey protein doesn't appear on the list of contraindicated substances to take with Synthroid, according to Drugs.com. However, mixing the two may not be a safe for some people. If you are taking Synthroid, ask your doctor about using whey protein at the same time.
Read the whey protein product's nutrition information label. It is not safe to ingest large amounts of calcium or iron when taking Synthroid, according to Meritus Medical Center. If the whey product is high in either, choose another version or avoid using it altogether.
Allow four hours between your dose of Synthroid and the ingestion of a whey protein product. Note the time when you swallow your thyroid pill; this allows you to determine whether enough time has elapsed before consuming whey protein.
Choose a whey protein product that contains less than 5 grams of fiber per serving. Your body digests high-fiber foods slowly, which may interfere with the absorption of Synthroid, even if you wait several hours to take it.
Take your Synthroid at the same time each day. This regulates its effectiveness but also allows you to include whey protein in your meal plan later in the day. Drugs.com recommends taking Synthroid in the morning.
Avoid whey protein products that contain cottonseeds, walnuts and soy. These ingredients reduce the absorption of Synthroid, making it less effective for treating your condition.