Is it normal to experience dizziness after taking synthroid (thyroxine)?

Unrelated: Hi. No, taking a l-thyroxine pill does not cause dizziness. If you're on too much l-thyroxine, you could conceivably have a heart rhythm & rate disturbance that could make you dizzy. If you know how to check your pulse, check it at rest; it shouldn't be above the 80's under normal circumstances. In all likelihood, your dizziness is due to something else. I would give your doctor a call. Good luck!