T3 or T4 What's the deal?

[is_wizer]

I bought a bunch of T4 accidentally.. Anyone have any experience with it? From what I'm reading, T4 is just not as strong and as effective. I'll throw it out if it wont yield similar results as T3.. Hell I only paid $2.80 for 200 50mg tabs..

Have I mentioned, I love it here!!!!!

Thanks in Advance!

 

[is_wizer]

Throw it out. Your body will only use T4 as needed.

Aight.. Thx bro!

 

[is_wizer]

Throw it out. Your body will only use T4 as needed.

I'm not doubting u at all bro but from what I read, I understand differently

From the Cytomel drug profile like I found the following:

https://thinksteroids.com/steroid-profiles/cytomel/

"It is interesting to note that L-T3 is clearly the stronger and more effective of these two hormones. This makes Cytomel more effective than the commercially available L-T4 compounds such as L-thyroxine or Synthroid"



Any other input would be greatly appreciated!

 

[einstein1905]

T4 is converted into T3. The body produces roughly 75mcg of T4/day, roughly 1/3 of that is converted into T3/day.
Don't throw it out, use it at 3x the dose you would T3. Keep in mind that things like ECA and clen increase the conversion of T4---> T3
Using T4 was pretty common a few years back.

 

[is_wizer]

T4 is converted into T3. The body produces roughly 75mcg of T4/day, roughly 1/3 of that is converted into T3/day.
Don't throw it out, use it at 3x the dose you would T3. Keep in mind that things like ECA and clen increase the conversion of T4---> T3
Using T4 was pretty common a few years back.

ahh.. Ok.. that sounds more like the research I found.

Thanks bro!

 

[einstein1905]

Look I'm no doctor but I do have a thyroid problem. This is how my doctor explained it to me. Your body produces t4 it converts it to t3 as needed. Normally as einstein1905 your thyroid gland secretes 75mg of t4 and your body converts 1/3 of it to t3. But that does not mean that if you take 150mg your body will convert 50mg to t3. Its a case of diminishing returns. You will probably get far less. This is why T4 and synthroid are prescribed far more than T3. Its hard to over dose on T4 if you take too much your body simply doesn't use it. Now I have overdosed on T3 and let me tell you its not fun. The main reason i told you to throw it out is the same reason my doctor got me off of sythroid. Synthroid and T4 suppress the thyroid gland to a much greater degree than T3. As my doctor put it "Your young if you take T3 there is a chance your thyroid gland will recover. If you take synthiod or T4 it will never recover."

Both T4 and T3 feed into the negative feedback loop to downregulate the thyroid. Saying "you'll never recover after taking T4" is a bit extreme and not very accurate.
You're right in saying that T4 won't continue to be converted at 67% to T3 at supraphysiological doses, but that's why I mentioned the clen and ECA. A great deal will still be converted to T3. Also, gugglesterones will help to restimulate thyroid function.

I hope doctor Demeur can chime in on this and shed some more insight.

 

[einstein1905]

What I ment was that while on T3 your thyroid can recover. It happened to my mother. But that will never happen while on T4.

That's not at all true. Many BBers used to take T4. I agree T3 is better because you can accurately dose it, but T4, like I said, was commonly used.
Actually, if you're going to run thyroid hormones for a longer duration, T4 would be the beter choice so that your body still does its own conversion to T3.
T4 will not shut you down faster or harder (sorry about saying that earlier)

 

[is_wizer]

That's not at all true. Many BBers used to take T4. I agree T3 is better because you can accurately dose it, but T4, like I said, was commonly used.
Actually, if you're going to run thyroid hormones for a longer duration, T4 would be the beter choice so that your body still does its own conversion to T3.
T4 will not shut you down faster or harder (sorry about saying that earlier)

Thanks for the input guys.. anyone else??

 

[is_wizer]

That's not at all true. Many BBers used to take T4. I agree T3 is better because you can accurately dose it, but T4, like I said, was commonly used.
Actually, if you're going to run thyroid hormones for a longer duration, T4 would be the beter choice so that your body still does its own conversion to T3.
T4 will not shut you down faster or harder (sorry about saying that earlier)

I appreciate all the input, can anyone else chime in???


Thanks!

 

[jboldman]

my understanding is that t4 converts at roughly 1/4 ratio to t3. There is no evidence that it will shut you down permanently and there is absolutley no truth in the belief that you will only convert what you need. Now it may not covert at exactly that ratio depending on your body, believe me, it works. The reason that t3 is NOT prescribed is because of the short half life. As was pointed out, t4 is very inexpensive.

jb

 

[einstein1905]

All right....

1. I take T3 everyday of my life to function normally not just to get thin.

2. I was on synthroid (synthetic T4). I was taken off of it because my mother's thyroid recovered after switching to T3 so there is a chance mine will to.

3. I did not say that T4 will shut you down permanently, although it can. I did say that while on it your thyroid will shut down. Which for me means permanently. T4 supplementation completely suppresses thyroid function; T3 only slightly retards it. This is because the hypothalamus monitors serum T4 levels through a negative feed back loop. When the levels are low it secretes thyrotropin-releasing hormone (TRH) which intern causes our pituitary to secrete thyroid stimulating (TSH), which stimulates the thyroid to produce T4 and some T3. The hypothalamus also monitors T3 but not to the same extent. In laymens terms while on T4 your thyroid will stop working, while on T3 it will only slow down, and if youre like me it might speed up.

4. Taking excess T4 while somewhat effective is really just a waste of money. I guarantee you don't have enough selenium in your body to convert much of what you take to active T3. T3 may cost more but it gets much better results.

T4 is very effective and was/is used by many BBers. Ant BBer's diet will provide a ton of selenium....then throw your multivitamins on top of that.....selenium will not be the rate-determiner.
You say T4 is more crucial in Thyroid negative feedback??? Not likely. T4, being primarily serum globulin bound (>99%) is more likely the less likely to effect negative feedback inhibition. Supplementing with T4 will not unequivocally shut down thryoid function. It will, in a dose dependent manner, contribute to thyroid negative feedback inhibition (most likely not to the degree that T3 does so) and cause the reduction of thyroid activity accordingly.

T3 is used because of its short half-life and its ability to be dosed very accurately.

 

[is_wizer]

All right....

1. I take T3 everyday of my life to function normally not just to get thin.

2. I was on synthroid (synthetic T4). I was taken off of it because my mother's thyroid recovered after switching to T3 so there is a chance mine will to.

3. I did not say that T4 will shut you down permanently, although it can. I did say that while on it your thyroid will shut down. Which for me means permanently. T4 supplementation completely suppresses thyroid function; T3 only slightly retards it. This is because the hypothalamus monitors serum T4 levels through a negative feed back loop. When the levels are low it secretes thyrotropin-releasing hormone (TRH) which intern causes our pituitary to secrete thyroid stimulating (TSH), which stimulates the thyroid to produce T4 and some T3. The hypothalamus also monitors T3 but not to the same extent. In laymens terms while on T4 your thyroid will stop working, while on T3 it will only slow down, and if youre like me it might speed up.

4. Taking excess T4 while somewhat effective is really just a waste of money. I guarantee you don't have enough selenium in your body to convert much of what you take to active T3. T3 may cost more but it gets much better results.

How long would I have to take T4 for my thyroid to shut down perminantly.. will 300 - 400mcg a day of t4 for about 2 weeks produce long term negative effects until I can get my hands on T3?

 

[is_wizer]

Listen Here einstein,

Knot only do I know from what I've read, what my endroconologist has told me, I also have my my own blood work. When I started taking T4 my TSH levels dropped form well below normal to nothing. When I switched to T3 my TSH rose back to where it had been before.

Your assertion that T4 doesn't shut down TSH production is laughable.

Look guys I'm not trying to start an arguement but I do appreciate all the input.. I just want to know if i can use t4 for a short period of time until my pharmacist gets the T3 in.. It's a mistery to me why T4 is so readily available if its such an obsolete drug and T3 is much harder to get my hands on.

Make sense??

 

[demeurj]

Look guys I'm not trying to start an arguement but I do appreciate all the input.. I just want to know if i can use t4 for a short period of time until my pharmacist gets the T3 in.. It's a mistery to me why T4 is so readily available if its such an obsolete drug and T3 is much harder to get my hands on.

Make sense??

There's a couple of problems here:
1) It is quite likely that everything Windigo is saying about his personal experience is TRUE but irrelevant.
2) Einstein 1905 is accurate in his assessment but it is definitely relevant.

The problem with Windigo's perspective is that there are MULTIPLE causes of hypothyroidism but we do not treat them identically. Thyroid, pituitary, and hypothalamic dysfunction can ALL cause clinical hypothyroidism. If it is appropriate to treat a particular form of hypothyroidism with synthetic thyroid, T3 (Cytomel) or T4 (Synthroid), then the choice is made based on the relative merits . . . not on suppression of thyroid. If a doctor is worried about suppressing the thyroid then they would NOT use ANY synthetic thyroid hormone.

The primary determinant in choosing a therapy is often cost. Synthroid is dirt cheap while Cytomel costs 5x more at clinically equivalent doses.

Several conditions are downright confusing. In sick euthyroid syndrome, T4 and T3 are low, TSH is normal, and there are NO clinical signs of hypothyroidism. In pregnancy, the proteins that carry thyroid hormone are upregulated. As these proteins bind up more hormone . . . the hypothalamus senses LESS hormone so it bumps up the production of T4 which is subsequently converted to T3. TBG (thyroxine binding globulins) are an integral part of thyroid regulation. So pregnant women have excess T4 and excess T3 but it doesn't matter b/c the excess TBG keeps FREE levels of these hormones close to normal.

Another factor is reverse T3 (rT3) which is biologically inactive but it's production is often comparable to T4 levels (so if you bump up T4 you will produce more rT3 from it).

http://www.drlowe.com/QandA/askdrlowe/thymetab.htm (accurate, concise explanation but does not address Windigo's contention that T4 inhibits the HPT axis more than T3)

The take home messages:
1) Synthetic thyroid hormone works but just like other forms of gear you are tinkering with a system that Mother Nature spent millions of years perfecting. It is highly unlikely that ANY particular drug will permanently damage the axis but I would treat T4/T3 more like insulin . . . ie you really need to know what you are doing . . . the margin for error between a good outcome and big time fudge up is far from idiot proof.

2) Your body will respond to exongenous thyroid hormone. T4 (Synthroid is cheap and effective) while T3 (Cytomel is more expensive and effective). A good comparison is codeine (T4) and morphine (T3). The liver whacks off a methyl group from codeine to produce morphine. You can take morphine or 3x as much codeine. The negative and positive consequences are a function of the active substances regardless of how you got there . . . but like all medicine there are ALWAYS caveats.

 

[einstein1905]

Excellent information....thanks for clearing things up.