Modafinil is a stimulant prescribed by doctors to treat people with chronic sleeping problems such as narcolepsy – where the person can fall asleep at anytime and without warning. It may also be prescribed for sleep apnoea and ADHD. It is used by the military in times of combat to keep soldiers awake for extended periods.

Non-medical use is thought to be on the increase, particularly among shift workers and students, who may use it to stay awake and improve their concentration and motivation.

The drug, though similar in some of its effects to Ritalin (used to treat attention deficit disorders in children) is not an amphetamine-related drug.


Modafinil comes as white tablets in 100mg and 200mg doses. In the UK, the trade name is usually Provigil.

Effects and risks

While Modafinil can keep the user awake for prolonged periods, it reportedly lacks the agitation, irritability and comedown associated with amphetamines. Physical effects include increased blood pressure and heart rate.

According to a research article published in the journal PLOS One, the most common adverse effects are headaches, nausea, nervousness, rhinitis, diarrhoea, anxiety and insomnia. In rare cases high doses may induce psychosis.

Like all drugs that keep you awake, long-term use can cause psychological and physical problems such as fatigue and disorientation – symptoms that can only be resolved through a good night’s sleep.

Doctors are not exactly sure how the drug works within the brain, although it is thought to act on dopamine and noradrenaline; neurotransmitters that affect mood.

The law

Modafinil is a prescription only medicine. It is legal to possess, but not to supply to others without a prescription.

Further reading:

The off-prescription use of modafinil: An online survey of perceived risks and benefits (2020)
This scientific paper reports on a detailed survey into the perceived experience of modafinil use and the modafinil user’s profile | PLOS One, February 2020, UK

Freshers warned to be smart and avoid Modafinil (2016)
MHRA highlight the pitfalls of buying medicines online to students | MHRA, UK

Updated November 2021