I think I got my temp up with l-tryptophan. I only take about 150mg -200 mg most nights ( I leave out occasionally) and maybe 50-75mg with my noon thyroid meds. I take up to a couple of days off occasionally.
My body temp has definitely come up lately but I'm not sure if its that or duphaston (a progestin) or progesterone.pr just menopausal related.
Oestradiol and oestriol also influences the body temp.. so its not clear to me exactly what is going on.

Serotonin (via tryptophan) also influences oestrogen.

But now I feel the heat, sweat and my skin even goes pinkish with exercise.. whereas before the best I'd do was a cold clammy sweat on a hot day with exercise occasionally.. reached this last year.

An internal temp of 37 or 98.6 (or lower depending on how measured)
http://hypertextbook.com/facts/LenaWong.shtml
is measured via a thermistor usually inserted somewhere inside.. like the stomach(inserted down throat via a wire attached to a thermistor) or inside an artery!. I think even the rectal measurements are considered lower than real core body temperature.

So it depends on WHERE you measure your internal body temperature as well as when.
http://www.biomedcentral.com/1472-6793/3/7
There's a circadian during day as well as month, as we all knew .. lower in morning on waking in bed, and higher in evening.
For females- higher during progesterone part of cycle; see family planning (rhythm method) temperature measurments or instrucins that come with a basal thermometer.

today 15/3/06 1.40PM about 30 mins to 45 mins after eating .. about day 14.. no progesterone:

Eating also raises your core temperature. But I figure I need about 37C a half hour after eating for good digestion.

(now I may have worked out why I used to feel better with 3 cuppas before, during and after a meal!!..down to one after and one before now, with brekkie and lunch)

Temps measured by alternating different thermometers e.g. use normal digital on left underarm and basal on right underarm., then swap, then switch again ,then switch again.In mouth alternate thermometers.

Temps should be taken consistently in a same temp room after resting(reading forum on computer or watching TV, reading etc for preferably an hour)

left underarm 35.8 36.0 right underarm 36.3 , 36.3 under tongue 36.9, 36.88 with a normal digital thermometer (rounded)
left underarm 36.1 36.0 right underarm 36.2, 36.1 under tongue 36.9 , 36.9 with a BD basal Accu-beep digital thermometer

I think mine have finally became normal.. since adding the tryptophan and oestriol .. but I can't prove its that, it may have just been more T4 as well.

More on measurement of temperature :

Body temperature measurement
T Togawa 1985 Clin. Phys. Physiol. Meas. 6 83-108 doi:10.1088/0143-0815/6/2/001