Helen (Houston, TX, USA) on 10/01/2014:

I tried L-Tryptophan several nights, thought one of the other substances was what kept me alert-awake. (I was taking several things at once - B3, herbs, etc, in desperate effort to get some sleep! Bad idea for figuring what is causing a worse problem instead of helping) I was having strange feelings in my chest which I now know to be heart palpitations.
Thinking no sleep meant I wasn't taking enough L-Triptophan (and that one of the other tools was causing the strange chest thumps), I upped from 500 mg to 1000 mg (2 pills) and took only L-Tryptophan (to eliminating, I thought, whatever was causing the chest spasms). But an hour after I got to bed wow was my heartbeat crazy! Like my whole chest was throbbing! Felt like a superslow beat 5 times the usual strength, but wrist pulse revealed a weak pulse beat in between the super big ones, so the rate was normal but the strength unusual. Really scary to have a resting heartbeat that intrudes on your awareness! Got up and searched for the half life - 1-2 hours. That was reassuring. An hour later my heartbeat was still too strong but far less so. (Food based L-Triptophan has a 10-12 hour half life because it's bound to protein; the pure supplement has a short half life.)
BTW, L-Triptophan supplement wearing off fast means it might be good for helping some people get to sleep but not keeping them asleep.
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Pam (Sacramento, Ca Us) on 02/13/2013:

Better But With Side Effects
I am a diabetic and have tried L-Tryptophan for sleep. It works great for sleep but it raises my blood sugar. I searched for articles regarding this and found many that stated tryptophan can cause a rise in blood sugar levels. I had excellent control of blood sugar levels and started taking tryptophan. Everytime I took this supplement at night my blood sugar would be high in the morning. When I quit taking it, no problem. Such a bummer too, because the tryptophan helped me get a good night sleep without prescription sleeping meds. I am going to try GABA now and see how that works.
Hope (Sacramento, CA) on 12/07/2008:

I have had insomnia for a good 10 or more years. I have tried everything and then read a book called The Mood Cure wherein I found the answer to my problems. Because I do not do well with 5HTP, I started using L-Tryptophan. I take 1500 mg each night before retiring - I open the capsules and mix them with a small amount of rice milk and shake well before drinking. I now sleep a good 7-8 hours straight through and awake feeling exceptionally refreshed and energetic!