For the past 10 years, on every long-haul flight over 12 hours, Singapore-based frequent flyer Brian Rogove has taken melatonin to combat jet lag.
"I think it's safe. It works about 75% of the time, and I don't have any odd side effects," he says.
Melatonin — a hormone produced by the pineal gland in the brain — helps initiate and maintain sleep. The melatonin widely available off-the-shelf is a synthetic version of the naturally-produced hormone.
"One way to think of melatonin is as an alarm clock for bedtime," says Dr. Caron Sak, a family physician at Tucker Medical based in Singapore. "It tells us it is time to go to sleep rather than actually making us sleep."
Jet lag is a desynchrony between the environment's light-dark cycle and the body's internal circadian rhythm that occurs when traveling across time zones faster than the body can adjust.
If used correctly, melatonin is an effective and safe treatment for jet lag, says Dr. Sak.
In most countries, melatonin can be purchased without a prescription. Synthetic melatonin is not regulated because it is not categorized as a drug.
"One concern is that the amount of melatonin in the product does not actually match what is listed on the label," says Dr. Sak. "You might be consuming a higher dose than what you need."
She advises that consumers use a well-known brand, starting with a low dose which can be increased, if necessary. She notes melatonin's effectiveness varies from individual to individual.
Ruby Shang, who splits time between the U.S., Singapore and Switzerland, prefers a Swiss-manufactured slow-release pill.
"I consulted doctors at the Mayo Clinic, who suggested a three-milligram dose for up to five days after travel," she says.
While a three-milligram dosage is closest to the body's natural melatonin production, some sleep doctors prescribe a five to 10-milligram dose taken 30 to 60 minutes prior to the desired sleep time.
Jet lag is worse going east, traveling against the natural direction of the sun. Eastward travel requires advancing the circadian system to adjust to the new time zone.
Doctors consider melatonin especially effective for eastward travel and for travel that lasts longer than three days.
For eastward travel, Dr. Sak suggests that adults take melatonin at bedtime for five days after arriving at their destination. Melatonin taken in the evening helps advance circadian rhythms to align with local time.
For westward travel, circadian rhythms run ahead of the destination time, so travelers end up waking earlier.
Here, melatonin can be taken in the morning, but use with caution as it might cause daytime sleepiness instead.
Dr. Arti Jaiswal, a US-trained pediatrician with Singapore's International Medical Clinic Children's office, says melatonin is safe for children aged three and older, but only for a short period of time.
"We don't know what the potential long-term effects can be, especially for young children," she says.
She recommends a 0.5-5 milligram dose for both children and adults.
Dr. Jaiswal says that while melatonin is effective for most children, a paradoxical side effect, like hyperactivity, can occur. While this is rare, she says, she advises trying melatonin at home before traveling.
If melatonin doesn't work, she says an antihistamine, such as diphenhydramine, can help with sleep as well.
Following this, Dr. Jaiswal suggests using melatonin on the plane to help children with sleep onset, or even starting the day before to assist the adjustment process. Children can take it in either liquid form or tablets, she says, though the timing is dependent on travel plans.
"It really depends on the destination and time difference," she says.
Though pills are most common, melatonin comes in many different forms.
Dr. Sak says immediate release forms, such as those that instantly dissolve in the mouth, work best for jet lag.
Frequent international traveler, Marvin Yeo agrees. He swears by Waferest melatonin wafers that dissolve under the tongue for optimized absorption.
"I've tried gummies and tablets, but I never knew how or when the dose was going to affect me," he says. "The dissolvable wafers consistently hit me about 20 minutes after I've taken one."
Melatonin is not recommended for pregnant and lactating women.
Users should avoid alcohol and other sedatives and check with a doctor for potential interactions with blood pressure medications, blood thinners, birth control pills and psychiatric medications.
Although there are no known major side effects of short-term melatonin use, anyone who experiences mild side effects such as headaches, dizziness or nausea, should consider whether using melatonin is worth it.