Desiccated Thyroid Extract - Thyroid Extract Proponents

Thyroid Extract Proponents

Desiccated thyroid is preferred by a growing body of patients and doctors who claim better relief of symptoms such as fatigue and depressed mood. Many proponents of desiccated thyroid feel passionately about the issue. .

A number of specific claims are commonly made about thyroid extract:

• Thyroid extract is better than thyroxine because it contains both T4 and T3, and both are made by a healthy thyroid gland.
• Doses should be increased until symptoms are relieved regardless of laboratory tests.
• Other constituents of the dried thyroid glands besides the T4 and T3 (e.g., unmeasured amounts of diiodothyronine (T2), monoiodothyronine (T1), calcitonin, other protein-bound iodine) may contribute to a perceived greater effectiveness or confer additional benefits.
• A product produced by farm, slaughterhouse, and factory is "natural", and therefore preferable to thyroxine molecules synthesized in a factory alone.

To endocrinologists the preference of some hypothyroid people for thyroid extract raises some important questions which current evidence cannot answer with certainty:

1. Is the reason some people fail to have complete relief of symptoms when tests show normal levels simply because there are other causes of fatigue, depression, and weight gain and these people are mistakenly attributing the problems to the thyroid and simply enjoying a placebo effect if they claim better relief from thyroid extract?
2. Does a combination of T4 and T3 provide more effective symptom relief for some people than T4 alone? Multiple controlled trials have shown inconsistent benefits of various ratios of T4 and T3. Even if most people with hypothyroidism enjoy complete relief of symptoms with thyroxine alone, are there people who need T3 as well because they cannot generate normal amounts from T4 as most people do?
3. Is the perceived benefit simply a result of overtreatment, such that the same relief could be achieved by pushing a thyroxine dose to higher levels?
4. Is the TSH measurement, and its associated 'normal' range, the best indicator of optimal replacement dose? Most research evidence suggests it is, but some patients feel better at doses which produce abnormally high blood levels of T4 and T3 and suppressed TSH. Is this simply a stimulant effect of high doses, similar to caffeine or amphetamine? How high is the risk of prolonged overtreatment to the bones, heart, and other parts of the body, and is it worth an improvement in subjective well-being?

Despite claims of proponents that desiccated thyroid pills are superior to thyroxine or combinations of T4 and T3 for most people with hypothyroidism, no controlled clinical trials have been published, and many physicians remain unconvinced that the superiority is anything other than a placebo effect or an overtreatment effect.