Re: Blood Draw

March 2, 2005

Plasma Circulation = 24 hours (give or take a 40 minutes), Half

life = 48 hours (give or take a few hours)

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=302152

Simultaneous Measurement of Thyroxine and Triiodothyronine

Peripheral Turnover Kinetics in Man

The normal mean T3 fractional turnover rate (kT3) was 0.68 (half-

life = 1.0 days), increased in toxic Graves' disease patients to

1.10 (half-life = 0.63 days), and decreased in primary hypothyroid

patients to 0.50 (half-life = 1.38 days). The mean T3 equilibration

time averaged 22 hr except in hypothyroid and high thyroxine-binding

globulin (TBG) patients where the equilibration period was delayed

by 10 hr.

http://www.uic.edu/classes/pcol/pcol425/restricted/Carley/thyroid.PDF

http://pediatrics.aappublications.org/cgi/content/full/107/4/e57

Determined by the log linear regression method of the 3 points in

the first 5 days, serum elimination half-life of FT4 and FT3

measured 50.3 hours and 84.9 hours, respectively.

The elimination half-life of T4 and triiodothyronine (T3) in acute

thyroxine ingestion is 2.8 days and 6 days, respectively.5

http://www.endocrineweb.com/tests.html

Since Euthyrox or Synthroid (and most other thyroid pills) behave

exactly as normal human thyroid hormone, they are not rapidly

cleared from the body as other medications are. Most thyroid pills

have a half life of 6.7 days which means they must be stopped for

four to five weeks (five half lives) before accurate thyroid testing

is possible. An exception to the long half life of thyroid

medication is Cytomel - a thyroid pill with a half life of only

forty-eight hours.

http://www.abbottdiagnostics.com/Your_Health/Thyroid/function.cfm

The metabolic effectiveness of T4 is decreased by agents that

inhibit T3 formation, indicating that much of the T4 activity stems

from formation of T3. This is further supported by the differences

in TBG binding affinity and half-life. T4 has a half-life of 6.7

days while T3 has a half-life in serum of only 1.5 days. It has

become apparent in recent years that T3 plays an important role in

the maintenance of the euthyroid state.

http://www.fda.gov/cder/foi/label/2002/10379s47lbl.pdf

Since liothyronine sodium (T3) is not firmly bound to serum protein,

it is readily available tobody tissues. The onset of activity of

liothyronine sodium is rapid, occurring within a few hours.Maximum

pharmacologic response occurs within 2 or 3 days, providing early

clinical response. Thebiological half-life is about 2-1/2 days

http://www.altsupportthyroid.org/t3.php

T4 is slow acting, with a half-life of about one week — after a

week, you have about half the level of the T4 still in your body, a

week or so later you have half of that half remaining, and so on.

Its full effects aren't reached until about six weeks after starting

or changing a dose, which is why lab tests are optimally done every

six weeks or so until a patient with hypothyroidism has reached

satisfactory and stable thyroid hormone levels. T3, on the other

hand, has a half-life of about a day. People on T3 sometimes feel

its effects within minutes after taking it.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=14697084

The elimination half-life was 24 hours 40 minutes. The charcoal

haemoperfusion had no impact on the velocity of elimination. The

concentration of triiodothyronine became normal 200 hours after the

intake of the latest capsule, but the clinical manifestations still

lasted three days more.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12193311

In the absence of a specific treatment, hemoperfusions were

performed but failed to accelerate significantly the decay of blood

levels of free triiodothyronine (apparent half-life 25.9 hours; 95%

confidence interval: 19.8-37.4 hours).

Demonstrated rise in plasma FT4 as much as 4 hours after

administatration of thyroxine:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=4031

After a dosage of 6 mg DT4 the D/L T4 plasma concentration rose

about 4-fold 4 hours after application and was only moderately

elevated 14 hours later.

> >>T3 has a half life of 48 hours, <<

>

> OK you're gonna have to show some proof of this! I have heard the

half life of T3 is more like 4-6 hours. I know I take Cytomel with

my Armour and I can FEEL when it drops off and I am due for the next

dosage.

> According to this body builder website T3 has a half life of

around 10 hours. http://www.muscletalk.co.uk/article-steroid-half-

life.asp

> And from Dr Lowe :

> Within a couple of hours after a patient ingests a single daily

dose of plain T3, the blood level of T3 peaks. The Internet doctors

infer that because the blood level of T3 peaks, the metabolic

reactions of body tissues also peak, resulting physiological

instability. Their inference is wrong.

> http://www.drlowe.com/QandA/askdrlowe/t3.htm

> Sorry this is the best references I can find.

> *Artistic Grooming * Hurricane, WV

> Old aunts used to come up to me at weddings, poking me in the ribs

and

> cackling, telling me, " You're next. " They stopped after I started

doing the

> same thing to them at funerals

>

March 2, 2005

This shows the half life in the BODY, not the blood. In the blood it is there

and gone much quicker. That was what Lowe said anyway.

*Artistic Grooming * Hurricane, WV

Old aunts used to come up to me at weddings, poking me in the ribs and

cackling, telling me, " You're next. " They stopped after I started doing the

same thing to them at funerals

March 2, 2005

No, read them all, plasma = blood.

There is a difference between 'peak' and 'half life'. T3 peaks in

about 4 hours, but degrades in 24-36 hours depending on metabolism

and protein binding capacity.

> This shows the half life in the BODY, not the blood. In the blood

it is there and gone much quicker. That was what Lowe said anyway.

> *Artistic Grooming * Hurricane, WV

> Old aunts used to come up to me at weddings, poking me in the ribs

and

> cackling, telling me, " You're next. " They stopped after I started

doing the

> same thing to them at funerals

>

March 2, 2005

Half life means that if you take in say 100 grams of something and

it has a half life of 5 days then, 5 days after you take in that

100grams you'll have 50 grams of it left in your system. 5 days

after THAT (10 days in total) you'll have half of that half left,

25grams, etc, etc ... it takes about 6 - 7 half lives before the

initial dose you took (the 100grams) is gone, so that would be 30-35

days.

> In a message dated 3/2/2005 2:17:11 PM Eastern Standard Time,

> gnattygrl@y... writes:

>

> > An exception to the long half life of thyroid

> > medication is Cytomel - a thyroid pill with a half life of only

> > forty-eight hours.

> >

>

> what i'm wondering....is how they know this? so i take 25 mcg at

noon...by

> noon the next day they are daying that 1/2 of that is still

there? i don't

> think so. somebody explain half-life to me.

> cindi

>

March 2, 2005

Half life means that if you take in say 100 grams of something and

it has a half life of 5 days then, 5 days after you take in that

100grams you'll have 50 grams of it left in your system. 5 days

after THAT (10 days in total) you'll have half of that half left,

25grams, etc, etc ... it takes about 6 - 7 half lives before the

initial dose you took (the 100grams) is gone, so that would be 30-35

days.

> In a message dated 3/2/2005 2:17:11 PM Eastern Standard Time,

> gnattygrl@y... writes:

>

> > An exception to the long half life of thyroid

> > medication is Cytomel - a thyroid pill with a half life of only

> > forty-eight hours.

> >

>

> what i'm wondering....is how they know this? so i take 25 mcg at

noon...by

> noon the next day they are daying that 1/2 of that is still

there? i don't

> think so. somebody explain half-life to me.

> cindi

>

March 2, 2005

In a message dated 3/2/2005 6:00:16 PM Eastern Standard Time,

.Ross@... writes:

> Etc. Glad

> you asked?

>

i wonder where i am in my own half life sequence.

cindi

March 2, 2005

In a message dated 3/2/2005 6:00:16 PM Eastern Standard Time,

.Ross@... writes:

> Etc. Glad

> you asked?

>

i wonder where i am in my own half life sequence.

cindi

March 2, 2005

In a message dated 3/2/2005 6:00:16 PM Eastern Standard Time,

.Ross@... writes:

> Etc. Glad

> you asked?

>

i wonder where i am in my own half life sequence.

cindi

March 2, 2005

In a message dated 3/2/2005 6:25:39 PM Eastern Standard Time,

gnattygrl@... writes:

> You're forgetting that before the half life would be over you'd have

> taken another 10mcgs, 2x.

no, i'm not forgetting. the reason I'm taking more is because i'm obviously

not feeling the half-life left in there. so i wonder what it does while it's

using up its life..and not being active....but just hanging around in my

blood? Or - i guess this means a certain level of T3 is required at all times

to

feel normal - which is why that one doctor recommends nibbling Cytomel.

cindi

March 2, 2005

In a message dated 3/2/2005 6:25:39 PM Eastern Standard Time,

gnattygrl@... writes:

> You're forgetting that before the half life would be over you'd have

> taken another 10mcgs, 2x.

no, i'm not forgetting. the reason I'm taking more is because i'm obviously

not feeling the half-life left in there. so i wonder what it does while it's

using up its life..and not being active....but just hanging around in my

blood? Or - i guess this means a certain level of T3 is required at all times

to

feel normal - which is why that one doctor recommends nibbling Cytomel.

cindi

March 2, 2005

In a message dated 3/2/2005 6:26:00 PM Eastern Standard Time,

gnattygrl@... writes:

> there are difference between hypot, hypers and euthyroids -

> it takes longer in hypos and much less time in hypers. It was one

> fo the first studies I quoted first.

>

sorry - i did miss that part. and i did read it.

but it was the 48 hours that stuck in my head.

but you're saying it took longer to clear in hypos?

cindi

March 2, 2005

In a message dated 3/2/2005 6:26:00 PM Eastern Standard Time,

gnattygrl@... writes:

> there are difference between hypot, hypers and euthyroids -

> it takes longer in hypos and much less time in hypers. It was one

> fo the first studies I quoted first.

>

sorry - i did miss that part. and i did read it.

but it was the 48 hours that stuck in my head.

but you're saying it took longer to clear in hypos?

cindi

March 2, 2005

In a message dated 3/2/2005 6:26:00 PM Eastern Standard Time,

gnattygrl@... writes:

> there are difference between hypot, hypers and euthyroids -

> it takes longer in hypos and much less time in hypers. It was one

> fo the first studies I quoted first.

>

sorry - i did miss that part. and i did read it.

but it was the 48 hours that stuck in my head.

but you're saying it took longer to clear in hypos?

cindi

March 2, 2005

In a message dated 3/2/2005 7:32:47 PM Eastern Standard Time,

laurie.brown@... writes:

> ...makes sense and all, but: you swallow 10 mcg of Cytomel, and how much

> of that gets absorbed from the intestinal tract?

oh yea...that's one of my problems...because only a certain amount is

absorbed anyway...and then i have malabsorption/intestinal disease stuff..so

that

really messes up everything

cindi

March 2, 2005

In a message dated 3/2/2005 7:32:47 PM Eastern Standard Time,

laurie.brown@... writes:

> ...makes sense and all, but: you swallow 10 mcg of Cytomel, and how much

> of that gets absorbed from the intestinal tract?

oh yea...that's one of my problems...because only a certain amount is

absorbed anyway...and then i have malabsorption/intestinal disease stuff..so

that

really messes up everything

cindi

March 2, 2005

In a message dated 3/2/2005 7:32:47 PM Eastern Standard Time,

laurie.brown@... writes:

> ...makes sense and all, but: you swallow 10 mcg of Cytomel, and how much

> of that gets absorbed from the intestinal tract?

oh yea...that's one of my problems...because only a certain amount is

absorbed anyway...and then i have malabsorption/intestinal disease stuff..so

that

really messes up everything

cindi

March 2, 2005

I don't feel any build up in my system at all from T3. That is a very good test

in itself as the amount I take if it built up even for a couple days I would be

in overload. I have seen my face in a mirror about 11:30AM when I have forgot my

11 Am dose. Bags are forming under my eyes and my eyes are half shut. Again it

happens around 4:30 PM. If I go even 15 MINUTES past 5 hours without taking some

more I feel that overwhelming tired come right back. I feel certain it is used

in different people at different rates too. Well actually some folks convert

their existing T4 when they need extra. I really don't think I convert at all

and that is why I feel when it is used up! LOL

*Artistic Grooming * Hurricane, WV

Old aunts used to come up to me at weddings, poking me in the ribs and

cackling, telling me, " You're next. " They stopped after I started doing the

same thing to them at funerals

March 2, 2005