L-tryptophan, an amino acid, is the metabolic precursor of serotonin, one of the neurotransmitters used by the brain to carry information from one part of the nervous system to another. Serotonin has general sedative effects. In theory, raising the level of L-tryptophan in the brain will cause increased production of serotonin and natural sedation.
L-tryptophan supplements were once popular as sleep aids, but in 1991 the FDA banned their sale in the United States after a contaminated batch from a Japanese manufacturer was linked to at least 37 deaths from eosinophilia myalgia syndrome, a rare and painful disease. The supplement again became available here in 2002.
I don't recommend using any sleeping aids, natural or not, on a regular basis, but for occasional use, I think there are better options than L-tryptophan:
- The herbal sedative valerian. Take one to two capsules of a product standardized to 1 percent valerenic acid a half hour before bedtime.
- Melatonin: This is a neurotransmitter that regulates the wake/sleep cycle and other daily biorhythms. Try sublingual tablets (to be placed under the tongue and allowed to dissolve); take 2.5 mg at bedtime as an occasional dose, making sure that your bedroom is completely dark.
I also recommend the following measures:
- Reduce or eliminate caffeine and other stimulants
- Get at least 45 minutes of aerobic exercise daily
- Take a relaxing hot bath before bedtime
- Practice daily breathing exercises. Try my relaxing breath.
- Try the "Healthy Sleep" CD I created with clinical psychologist and sleep specialist Rubin Naiman.
Learn more about other approaches to insomnia.
Andrew Weil, M.D.