A 200mg dose of modafinil, such as Modvigil 200, typically lasts 12 to 14 hours. Its effects begin within 30 to 60 minutes after ingestion and peak around 2 to 4 hours later. Many users report enhanced alertness, focus, and reduced fatigue throughout the day. Modvigil 200 is commonly used for conditions like narcolepsy or shift work sleep disorder. Duration may vary based on individual metabolism, age, and health. Always use Modvigil 200 under medical supervision to avoid side effects like insomnia, anxiety, or headaches, and never exceed the prescribed dose.