# Desiccated thyroid extract: T4/T3 variance in a dose? **URL:** \ **Category:** Factual Questions\ **Created:** [October 5, 2012, 1:39am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762 "2012-10-05T01:39:24Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 5, 2012, 1:39am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/1 "2012-10-05T01:39:24Z")
Mrs. Tracer has Hashimito’s thyroiditis, a very common variety of hypothyroidism. She’s gotten her hands on a self-help book called _Stop the Thyroid Madness_, whose author seems to feel that desiccated thyroid extract (the hypothyroidism treatment used before synthetic T4 became the word of the day) is the Way, and the Truth, and the Light; and that the “evil pharmaceutical industry” has been duping us all into believing that synthetic T4 is a better treatment option in order to bolster their bottom line. One of the “big lies” that the Evil Pharmaceutical Companies[TM] have been touting, at least according to this book, is that doses of synthetic T4 are carefully controlled so that each pill never has less than 95% or more than 105% of the dose it’s supposed to have; whereas desiccated thyroid extract, being made out of ground-up pig thyroids, can have levels of T3 and T4 that are all over the map. The _Thyroid Madness_ book claims that, since desiccated thyroid extract is regulated by the FDA, its dosage _must_ be consistent. :rolleyes: I wanted to find out just how tightly controlled the T4 and T3 levels in standard desiccated thyroid extract actually were, and how much variance really was allowed. The problem is, I couldn’t find _any data_ on this subject one way or the other. Wikipedia’s article on desiccated thyroid extract says that _historically_, it was regulated only by the level of iodine found in each dose, and that this was allowed to vary by as much as 15%, and that a widely publicized investigation published in JAMA revealed large ranges of hormone content and potency in all of the available thyroid extracts on the American market. But it’s silent on how it’s regulated **today**. Worse, when I looked on the USP’s website for the Reference Standard (at [USP Reference Standards](http://www.usp.org/reference-standards/find-reference-standard) ), I couldn’t find any reference standard in their alphabetical listings for either “thyroid” or “desiccated thyroid”. (I could, however, find reference standards for such substances as metformin, codeine, and even pharmaceutical cocaine.) So … what **are** the current standards of “purity” or dosage strength for desiccated thyroid extract, and how are the samples measured to ensure that they meet those standards? ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 5, 2012, 2:18am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/2 "2012-10-05T02:18:12Z")
Hmmm! Here’s a blog page written by an endocrinologist who seems to feel that desiccated thyroid extract is the Black Blood of Satan Himself: > **[Endocrinology News - Healio](https://www.healio.com/endocrinology?rid=35717)** > > Endocrine Today - Find clinical endocrinology news articles, videos, blogs, books, Continuing Medical Education (CME), meeting coverage, and journal articles from the #1 online source for endocrinologists, Endocrine Today. In that article, he makes the following claim: > [@](#): > > According to the American Society of Health-System Pharmacists “Big Red Book,” the mean concentrations of levothyroxine and liothyronine in each 60 mg of desiccated thyroid ranged from 8.8 mcg to 59 mcg and 7.9 mcg to 18 mcg, respectively. If that is correct, that’s a pretty huge variation, especially for levothyroxine levels (i.e. it’s anywhere from 25% to 168% of the levels that are supposed to be in the dose!). ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 5, 2012, 3:46am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/3 "2012-10-05T03:46:08Z")
Unfortunately, I just realized that the article doesn’t say WHICH EDITION of the Big Red Book he’s getting those figures from. I presume he’s talking about this one: [http://www.tower.com/manual-for-pharmacy-technicians-4th-edition-american-society-health-system-paperback/wapi/111728087?download=true&type=1](http://www.tower.com/manual-for-pharmacy-technicians-4th-edition-american-society-health-system-paperback/wapi/111728087?download=true&type=1) … but I can’t be sure if he was using the current (4th) edition or not. And of course, that still doesn’t tell me what the current USP standards for purity are SUPPOSED to be. ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [October 5, 2012, 4:18am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/4 "2012-10-05T04:18:29Z")
Thyroid extract is allowed to vary by +/- 15%. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 5, 2012, 1:53pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/5 "2012-10-05T13:53:52Z")
> [@Nametag](#): > > Thyroid extract is allowed to vary by +/- 15%. Much as I’d like to believe this statement on the face of it, Mrs. Tracer probably _won’t_ unless it’s backed up by a cite. For all I know, that 15% figure might be taken from the old, pre-1980 standards that specified only iodine content. Is there a specific FDA regulation or USP ref. standard (with year!) that you can point me to and/or quote directly from? ---
**Author:** ![Theobroma](https://avatars.discourse-cdn.com/v4/letter/t/b5a626/32.png) [@Theobroma](https://boards.straightdope.com/u/Theobroma)\ **Post date:** [October 5, 2012, 7:10pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/6 "2012-10-05T19:10:22Z")
I haven’t looked up the variation on dessicated thyroid, but I can tell you that the theory that drug companies are making bank on T4 is ridiculous. I have Hashimoto’s as well and have been taking T4 (Levoxyl specifically) for years, and it’s so cheap it’s virtually free. Some (few) folks prefer the dessicated thyroid on the grounds that it contains T3 as well as T4, and also that it’s more “natural”, as indeed it is. ---
**Author:** ![OtisCampbellWasRight](https://avatars.discourse-cdn.com/v4/letter/o/d78d45/32.png) [@OtisCampbellWasRight](https://boards.straightdope.com/u/OtisCampbellWasRight)\ **Post date:** [October 5, 2012, 7:17pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/7 "2012-10-05T19:17:25Z")
Dear OP: My soon-to-be-Ex wife has wrestled with thyroid issues for years, and has finally settled on the old-style medication derived from pig organs. She can go from being totally lethargic and sullen to a raving lunatic in a matter of minutes, so my advice to you (and her) is to do your research carefully. And good luck. ☹ ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 5, 2012, 8:03pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/8 "2012-10-05T20:03:33Z")
> [@OtisCampbellWasRight](#): > > Dear OP: My soon-to-be-Ex wife has wrestled with thyroid issues for years, and has finally settled on the old-style medication derived from pig organs. > > She can go from being totally lethargic and sullen to a raving lunatic in a matter of minutes, so my advice to you (and her) is to do your research carefully. Interesting. Does the transition from lethargic-and-sullen to raving-lunatic happen to coincide with the times of day when she takes the thyroid medication? ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 5, 2012, 8:11pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/9 "2012-10-05T20:11:07Z")
> [@Theobroma](#): > > I haven’t looked up the variation on dessicated thyroid, but I can tell you that the theory that drug companies are making bank on T4 is ridiculous. I have Hashimoto’s as well and have been taking T4 (Levoxyl specifically) for years, and it’s so cheap it’s virtually free. I’m glad to hear that T4 supplementation is sufficient for your needs. (At least, I hope it’s sufficient.) Mrs. Tracer’s switched endocrinologists earlier this year, because her previous one insisted on using the old 5.0 mUI/l top-end for the range of allowable TSH levels and wouldn’t budge regardless of her symptoms. Her current endocrinologist has her on brand-name Synthroid rather than generic levothyroxine. It’s my understanding that the brand name is more expensive than the generic, and that Abbot Labs (who owns the brand name) sells so much of the stuff that they can make up for low per-dose costs by sheer volume of sales. (According to [List of largest selling pharmaceutical products - Wikipedia](http://en.wikipedia.org/wiki/List_of_bestselling_drugs) , sales of Synthroid amounted to $534 million in 2006, and according to [When will the SYNTHROID patents expire, and when will SYNTHROID go generic?](http://www.drugpatentwatch.com/ultimate/preview/tradename/SYNTHROID&archive=2010) , sales of Synthroid amounted to $506,860,000 in 2010.) ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [October 5, 2012, 9:07pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/10 "2012-10-05T21:07:55Z")
I have never known an endocrinologist who prescribes desiccated thyroid. To a person, they use T4 (+/- T3). In addition to the potential problem of variation in its content, desiccated thyroid was also felt by some to have a liability in that it contains T3 already formed and thus overrides physiologic control. In other words, by giving preparations of pure T4, one leaves it to the body (i.e. the pituitary) to control how much of the active hormone, T3, gets generated (via TSH control, with TSH stimulating the conversion of T4 ==\> T3). On the other hand, giving T3 as part of the supplement removes this ‘brake’ on the system. In fact, [it may actually be desirable to use both T4 and T3 in combination to treat hypothyroid individuals](http://jcem.endojournals.org/content/97/7/2256.abstract). That said, desiccated thyroid (with its varying composition) would not be the way to do so; it would make more sense to use precise amounts (and ratios) of each of T4 and T3 ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 5, 2012, 10:20pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/11 "2012-10-05T22:20:26Z")
> [@KarlGauss](#): > > In fact, [it may actually be desirable to use both T4 and T3 in combination to treat hypothyroid individuals](http://jcem.endojournals.org/content/97/7/2256.abstract). Indeed, according to Lawrence E. Mallette (an endocrinologist who responded to an Endocrine Today blog post [here](http://www.endocrinetoday.com/comments.aspx?rid=35717)), “We now know that people who inherit two low-affinity alleles of the main deiodinase enzyme - one from each parent - show lower free T-3 levels while taking T-4 replacement. They don’t convert T-4 to T-3 well.” He also says “The pituitary is set up to read blood T-4 levels preferentially over T-3, so it may not sense a deficiency of circulating T-3.” I just wish Mrs. Tracer’s endocrinologist wasn’t so adamantly insistent on prescribing “T4 only”. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [October 5, 2012, 11:25pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/12 "2012-10-05T23:25:35Z")
> [@Theobroma](#): > > Some (few) folks prefer the dessicated thyroid on the grounds that it contains T3 as well as T4, and also that it’s more “natural”, as indeed it is. True, if you’re a pig or a cow. Bovine thyroid extract is also on the market, which would make me uneasy considering the possibility that infection (such as the agent of mad cow disease) could potentially be transmitted through such products. Speaking of “natural” supplements, it’s been found that so-called 'thyroid support" supplements may contain actual thyroid hormone, putting users at risk of hyperthyroidism if they’re using supplements in addition to hormone replacement therapy. The bottom line for me on crude thyroid extracts is that they likely vary too much in terms of active ingredient content for reliable dosage. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [October 6, 2012, 12:40am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/13 "2012-10-06T00:40:05Z")
One of the largest producers of dessicated thyroid is Armour, maker of Spam. I concur with my colleagues when they recommend just saying no to the dessicated product. And for similar reasons The American Academy of Family Physicians also says ‘no’ to dessicated thyroid, a fact they re-iterated to me today in a review of thyroid disease lecture. Thyroid! Armour Thyroid! What kind of doc gives Armour Thyroid? Non-mainstream docs. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [October 6, 2012, 1:06am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/14 "2012-10-06T01:06:57Z")
> [@tracer](#): > > Interesting. Does the transition from lethargic-and-sullen to raving-lunatic happen to coincide with the times of day when she takes the thyroid medication? I am interested in this too, as 4 of my 5 last thyroid measurements indicated a slightly underactive thyroid and there is hypothyroidism in my family. I’m still gonna try medication once my next test comes in especially since I’ve been really tired lately, but I’d like to know what to expect from it 🙂 ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [October 6, 2012, 3:47am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/15 "2012-10-06T03:47:19Z")
Slightly off-topic, but in the “Weird But True” category, there was an outbreak of symptomatic hyperthyroidism in the Midwest in the mid-1980s. It was traced to a meat processing plant that improperly used neck trimmings from cows, resulting in thyroid tissue getting into the meat and producing [“hamburger thyrotoxicosis”](http://www.ncbi.nlm.nih.gov/pubmed/3561455). ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 7, 2012, 1:35am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/16 "2012-10-07T01:35:31Z")
> [@Qadgop\_the\_Mercotan](#): > > One of the largest producers of dessicated thyroid is Armour, maker of Spam. Incorrect. The **BRAND NAME** is Armour. It was **originally** produced by the makers of Spam, as in, back in 1909. Today, it’s sold by Forest Laboratories, Inc. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 17, 2012, 11:58pm UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/17 "2012-10-17T23:58:06Z")
> [@tracer](#): > > > [@](#): > > > > According to the American Society of Health-System Pharmacists “Big Red Book,” the mean concentrations of levothyroxine and liothyronine in each 60 mg of desiccated thyroid ranged from 8.8 mcg to 59 mcg and 7.9 mcg to 18 mcg, respectively. > > Unfortunately, I just realized that the article doesn’t say WHICH EDITION of the Big Red Book he’s getting those figures from. I presume he’s talking about this one: > > [http://www.tower.com/manual-for-pharmacy-technicians-4th-edition-american-society-health-system-paperback/wapi/111728087?download=true&type=1](http://www.tower.com/manual-for-pharmacy-technicians-4th-edition-american-society-health-system-paperback/wapi/111728087?download=true&type=1) > > … but I can’t be sure if he was using the current (4th) edition or not. Turns out, that’s not the “Big Red Book”. This is: [http://www.pohly.com/books/ahfs-di.html](http://www.pohly.com/books/ahfs-di.html) I managed to get my hands on a slightly-used 2010 edition of this monstrous 4000-page tome, and found the reference the top-quote was mentioning. Unfortunately, while the 2010 Big Red Book did in fact mention these figures, it didn’t give a CITE for the study that this data comes from. No year, no journal name, no nothin’. Is there a not-too-difficult way to find out which study these data come from? ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [October 18, 2012, 12:41am UTC](https://boards.straightdope.com/t/desiccated-thyroid-extract-t4-t3-variance-in-a-dose/636762/18 "2012-10-18T00:41:24Z")
> [@Nametag](#): > > Thyroid extract is allowed to vary by +/- 15%. [This page](http://ruthroland.wordpress.com/2012/07/18/rumours-about-dessicated-thyroid-i/) seems to imply that the USP guidelines for desiccated thyroid only allow a dosage variation of +/- 10%. The page claims to be written by a medical director at Erfa Canada, who sells desiccated thyroid, but it mentions “USP standards” in a different sentence from “accepted difference in dosage” – the +/- 10% difference might be Erfa’s own manufacturing standard, not the USP standard.