Considering melatonin? It's best to proceed cautiously

By Dr. Landis Lum

Q. Every time I fly to the Mainland, I get tired and moody for several days from jet lag.

Does melatonin really work?

A. Melatonin is a hormone secreted by the pineal gland when it gets dark. It helps set your wake-sleep cycle.

The Cochrane database, an excellent resource, found melatonin remarkably effective in preventing or reducing jet-lag, and occasional short-term use appeared safe. However, four of six melatonin products bought in the United States were found to contain unidentified impurities.

Remember the supplement L-tryptophan, used as a "natural" sleep aid and mood enhancer? The pineal gland synthesizes melatonin from L-tryptophan — but when taken as a supplement, L-tryptophan caused the so-called eosinophilia-myalgia syndrome in 1989, which sickened more than 1,500 people and caused at least 37 deaths.

It turns out that this was likely due to contaminants formed during manufacture of L-tryptophan. Mayo Clinic researchers have since found these same contaminants in three separate samples of melatonin!

Because the FDA does not regulate melatonin, you can never be sure about it’s safety and purity. As the British Medical Journal said earlier this month, it seems advisable to buy it from a large reputable pharmacy chain or manufacturer and hope for the best.

Those who developed eosinophilia-myalgia syndrome ingested L-tryptophan continuously and in large amounts. Using melatonin occasionally should reduce its dangers. However, children or people with epilepsy should not take it, nor should anyone on warfarin or another oral anticoagulant.

Jet lag is worse if you travel from west to east. Natural light also helps reset your internal clock, so be outdoors as much as possible. If you've had problems with jet lag before and decide to try melatonin, then after arrival take two to five milligrams at bedtime the next two to five days.

The July 2001 issue of Aviation Space & Environmental Medicine reported a randomized study out of Switzerland in which the sleeping pill Ambien (zolpidem) actually worked better than melatonin for jet lag. People also slept better on the night flight back to Switzerland. But Ambien also caused more side effects, including nausea, amnesia and day drowsiness.

Incidentally, long flights or car trips can lead to dangerous blood clots in your calf. If you can't get up and walk at least once an hour, then point your feet up and down repeatedly for 1 minute every 15 minutes to prevent clots from forming, especially if you're overweight.

Dr. Landis Lum is a family practice physician for Kaiser Permanente and an associate clinical professor at the University of Hawai'i's John A. Burns School of Medicine.