You'll feel good about taking Mucinex because it's the only FDA-approved, 12 hour extended-release guaifenesin that provides relief in a convenient bi-layer tablet. The white layer immediately releases the medicine. The blue layer works steadily to release medication hour after hour, for 12 hours. Plus, Mucinex is convenient to take. Just one dose lasts for 12 hours, which is a lot longer than a dose of the leading cough remedies. That's good news when you can't have congestion slowing you down.