Thyroid stimulating hormone (TSH) is the hormone produced by your pituitary gland to control the function of your thyroid gland. A high TSH means your pituitary senses that your thyroid is underactive.
Many labs are misleading physicians by using outdated ranges of normal for TSH, thus preventing doctors from giving their patients the most effective thyroid treatment they need.
The National Health and Nutrition Examination Survey (NHANES III) demonstrated that the mean TSH in apparently normal, healthy participants is 1.4 uIU/mL.
Based upon the results of NHANES III, The National Academy for Clinical Biochemistry has recommended since 2002 that a serum TSH level between 0.5-2.0 uIU/mL be considered the optimal therapeutic target for replacement treatment of hypothyroidism.
There are several studies showing that any TSH above 2.5 is associated with metabolic syndrome, insulin resistance, elevated fasting triglycerides, elevated blood pressure, and higher body mass index. Here is one representative study:
This study found that subjects with a TSH in the upper “normal” range (2.5-4.5) had a significantly higher BMI, higher fasting triglycerides, and their likelihood for fulfilling the ATP III criteria of the metabolic syndrome was 1.7 fold increased. The study concluded that a TSH above 2.5 is associated with an unfavorable metabolic profile.
In the event your TSH is above 2.0 it is my opinion you should first NOT accept this as normal and second you should seek a health professional knowledgeable in the identification and treatment of thyroid disorders.
Most physicians will ignore a TSH of 2.0 and insist that this is normal.
I beg to differ and would suggest that you demand that your doctor order a total T4 and T3 and a free T4 and T3. I would also recommend you ask your doctor to order an Anti-thyroid peroxidase (anti-TPO), Thyroglobulin Antibodies (TgAb).
I have worked with many patients who were told their TSH was perfectly normal and soon discovered after running the above labs they had full blown Hashimoto's Disease. This is an auto-immune disease of the thyroid.
Don't be a victim to what some doctors consider a normal TSH. Fight for your right to achieve optimal health.
Ruhla S, Weickert MO, Arafat AM, Osterhoff M, Isken F, Spranger J, Schöfl C, Pfeiffer AF, Möhlig M. A high normal TSH is associated with the metabolic syndrome. Clin Endocrinol (Oxf). 2010 May;72(5):696-701