Does semaglutide expire after 28 days once opened? Yes. Most semaglutide pens (copyright® or Wegovy®) should be used within 28 days after first use. Once opened, the pen is kept at room temperature (up to 86°F / 30°C) or refrigerated, but after 28 days, it should be discarded even if medication remains.  Why does semaglutide expire in 28