Date: Tue, Jan 11, 2011 at 11:40 AM
Subject: Thyroid works better taken at bedtime
Take Thyroid before bed rather than in the morning
Jacob Schor, ND, FABNO
January 10, 2011
Most doctors have long advised their patients who take thyroid
replacement hormone to take it first thing in the morning without
It turns out that this is a mistake, or at least seems to be a
mistake. A December 2010 paper suggests taking it before bed is more
A number of years ago N. Bolk and colleagues at the Erasmus Medical
Centre, Rotterdam, The Netherlands, noticed several patients who
appeared to respond better to thyroid hormone administered at night.
They conducted a small pilot study in which they carefully tested
thyroid blood values in 12 women who were taking their thyroid in the
morning and then switched them to nighttime dosing for two months
prior to retesting. Their conclusion, published in 2007, “l-thyroxine
[T4] taken at bedtime by patients with primary hypothyroidism is
associated with higher thyroid hormone concentrations and lower TSH
concentrations compared to the same l-thyroxine dose taken in the
No one believes little pilot studies, especially ones that rock
accepted doctrine like this, so they ran a large double blinded
placebo controlled crossover study.
From April 2007 to November 2008, they enrolled 105 consecutive
patients with primary hypothyroidism. For 6 months patients took a
different pill morning and evening, one of which was placebo. After 3
months, the patients witched which pill they took in the morning.
Results of this larger study were published in the December 2010 issue
of the Archives of Internal Medicine.
Data from ninety of the patients who completed the trial were
analyzed. Taking thyroid at night decreased TSH level by 1.25 mIU/L,
increased free T4 level by 0.07 ng/dL and increased total T3 by 6.5
Night time dosing seems to be clearly superior. So much so that I am
wondering from where this idea of morning dosing originated. No doubt
someone will do the necessary homework and tell us the answer in the
There is a potential problem with this. If your TSH is in the 3-5.0
mIU/L range, it should not be a problem. If you have been taking
thyroid medication in the morning, and your TSH is in our target range
of between 1 and 2 mIU/L and you were to switch to evening dosing, you
might need to decrease the amount of medicine you take.
This information should prompt an editorial on our easy assumption
that standard medicine is evidence based. Suffice to say, much of
what we assume to be based on scientific evidence, is still, more
often than not, based on habit, tradition, circumstance and guesswork.
Thyroid test conversion numbers. I need to save these somewhere easy
to find, so why not here?
To convert TSH to micrograms per liter, multiply by 1.0; free
thyroxine level to picomoles per liter, multiply by 12.871; and total
T3 level to nanomoles per liter, multiply by 0.0154.
 Bolk N, Visser TJ, Kalsbeek A, van Domburg RT, Berghout A. Effects
of evening vs morning thyroxine ingestion on serum thyroid hormone
profiles in hypothyroid patients. Clin Endocrinol (Oxf). 2007
 Bolk N, Visser TJ, Nijman J, Jongste IJ, Tijssen JG, Berghout A.
Effects of evening vs morning levothyroxine intake: a randomized
double-blind crossover trial. Arch Intern Med. 2010 Dec