Provigil (modafinil) typically starts to work 30 to 60 minutes after you take a dose. The drug’s effects peak about 2 to 5 hours later. Provigil’s effects may continue for up to 11 hours or more.

Provigil comes as an oral tablet and is available in two strengths: 100 milligrams (mg) and 200 mg. The typical dosage when prescribed for obstructive sleep apnea or narcolepsy is 200 mg per day taken in the morning. When prescribed for shift work sleep disorder, the usual dose of Provigil is 200 mg taken once about an hour before your shift begins.
How long it takes for Provigil to start working varies by person and can be influenced by factors like your diet and other health conditions you have. But, in general, Provigil usually starts working about 30 to 60 minutes after you take a dose.
Provigil peaks in your bloodstream 2 to 4 hours after you take a dose. This can be delayed by about an hour if you take your dose with food.
When taken in the morning, Provigil has been shown to improve wakefulness until mid-afternoon. Another study showed that modafinil (the active ingredient in Provigil) helped with alertness for approximately 11.5 hours. It also showed the drug had far fewer side effects than other drugs taken to help with alertness, such as amphetamines and caffeine.
Provigil has a half-life of approximately 15 hours. (This is the length of time it takes for your body to get rid of half of the amount of a drug.) If you have liver problems or kidney problems, it may take a lot longer for the drug to be cleared from your system. Because of this, the half-life is longer and your doctor will likely prescribe a lower dose than 200 mg per day for you.
How long Provigil stays in your body depends on various factors, such as your age, liver function, and the dose of the drug you’re taking. But typically, the drug is detectable in your system for about 3 days.
Note: Because of the possibility for misuse, Provigil is a controlled substance in the United States. This means it has an approved medical use but may be misused for other purposes. It also means government agencies, doctors, and pharmacists pay close attention to how the drug is prescribed and used.
While modafinil is not usually included in drug tests for employment, it is on the World Anti-Doping Agency’s list of prohibited drugs for professional athletes.
Talk with your doctor if you have questions about how long you can expect Provigil to help with daily alertness based on your individual circumstances. If the drug is not effectively managing your sleepiness, your doctor may adjust your dosage or recommend a different treatment.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.