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T-mag Article By Brock Strasser : Issue No. 200, March 15, 2000
Thyroid Hormones = Permanent Suppression?
For years, many of us have been repeating, with little scientific evidence, that if you used too much thyroid hormone for too long you'd permanently screw up your brain/thyroid axis, end up with a permanent case of hypothyroidism and be a fat, slow slob on maintenance level Synthroid (T4) for the rest of your life.
This "urban legend" was first postulated by my mentor, Dan Duchaine (may peace be upon him) and propagated further over the years by a bunch of "fitness queens" who lived on Cytomel, looked great, ate like truck drivers and got as big as a leather couch when they stopped the Cytomel. For years, we blamed it on some thyroidic suppression. Well, folks, we wuz' wrong!
I've been listening to the experience of a guy named "Raver" on a
steroid message board and have been monitoring his experiences with Cytomel over the last year. Raver is convinced that T3 does not cause permanent suppression, even at 150-300 mcg per day for long periods of time. And it turns out, he was 100% correct!
Make no mistake about it, using exogenous thyroid hormones will suppress your own production of endogenous thyroid hormone and you will be hypothyroidic for a few weeks when you come off. But as many people can tell you, this state isn't permanent. This got me to thinking, so I started snooping around the medical school library archives. I soon dug up an old article from the NEJM for your perusal and I only wish I'd discovered this thing five years ago. Check it out:
N Engl J Med 1975 Oct 2;293(14):681-4
Recovery of pituitary thyrotropic function after withdrawal of prolonged thyroid-suppression therapy.
Vagenakis AG, Braverman LE, Azizi F, Portinay GI, Ingbar SH.
The pattern of thyrotropin secretion was analyzed in seven euthyroid women, before and after withdrawal of long-term thyroid hormone, by serial measurements of thyroid 131l uptake, serum thyroxine, tri-iodothyronine, and thyrotropin concentrations, and the response to thyrotropin-releasing hormone. During exogenous hormone administration, 131l uptake was suppressed, and serum thyrotropin concentrations before and after administration of thyrotropin-releasing hormone were undetectable.
After withdrawal of exogenous hormone, thyrotropin secretory function was transiently impaired, as indicated by undetectable basal thyrotropin concentrations together with absence of response to thyrotropin-releasing hormone, and subsequently by normal values of basal thyrotropin concentration and normal responses to releasing hormone while serum thyroxine and tri-iodothyronine concentrations were subnormal.
Decreased thyrotropin reserve persisted for two to five weeks. Detectable values of serum thyrotropin (less than 1.2 muU per milliliter) and a normal 131l uptake usually occurred concurrently in two to three weeks. Serum thyroxine concentration returned to normal at least four weeks after hormone withdrawal.
Translation: At least in women (and I'd venture to say men, too) the body will bounce back to baseline in a month or so. This is important information for people using any type of thyroid-based drug to lose fat. It should tell you that you need to be really vigilant for about a month after stopping such drugs with regard to diet and cardio.
Thanks, Raver!
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Link to T-mag article:
http://www.testosterone.net/articles/200use.html
Kudos to Raver's T-3 Recommendations
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