Thyroid Disorders Community
26k Members
Avatar universal


Have been taking SYNTHROID 50 micrograms for 3 weeks . Mostly the experience has been positive EXCEPT the severe constipation
My endocrinologist said this is not the side effect of SYNTHROID .
Is there a better alternative ?
40 Responses
Avatar universal
Constipation is more likely a symptoms of still being hypo.  Do you have other symptoms of being hypo, like the 26 typical symptoms shown in this link?


Also, please post your thyroid related test results and their reference ranges shown on the lab report so that members can better assess your testing and treatment.
Avatar universal
That severe constipation scares me so I stopped the Synthroid . I took Metamucil everyday trying to take care of this with no avail.

here is my level before treatment  1 year ago :

TSH  7.0  ( normal from 0,.4 -  4.5 )
FT4  1   ( Normal fr 0.8 - 1.8 )

and the same results also were obtained recently prior to treatment.

Yes, I do have the symptoms . Weight gain,  high chlesterol ( 235 , usually between 185 - 200 ) , and high blood pressure that is difficult to control with medication , less energy and slower memory.  

My PCP not sure if I have subclinical hypo which should be treated so I was refered to an endocrinologist . The endo believes I have hypo so started me with 50 micrograms of Synthroid .  After 2 weeks, severe constipation began.
Avatar universal
also ,  T3 uptake  35  ( range from 22 - 35 % )
Thyroid Peroxidase AB normal    26  (  normal < 35 )

Thyroglobulin AB  (< 20  ( normal < 20 )
Avatar universal
You said the the same results were obtained recently prior to treatment.   Do you mean that the TSH and FT4 test results were exactly the same as before?

You are missing the most important thyroid test, which is for Free T3.  FT3 largely regulates metabolism and many other body functions.  Scientific studies have shown that it correlated best with hypo symptoms, while Ft4 and TSH did not correlate.  In the future, you should always make sure to be tested for Free T3, along with Free T4 and TSH.  You probably should go ahead and get those tests done now to better understand your  current status.  

Many patients  find that when they start the meds, the TSH will go down and the thyroid gland will produce less natural thyroid hormone; therefore, there will be very little or no effect on test results and symptoms until the dosage is increased enough to raise the levels of FT3 and FT4.  Many patients, myself included, report that symptom relief for them required Free T3 to be adjusted into the upper third of its range and Free T4 adjusted to around the middle of the range.

A good thyroid doctor will treat a hypo patient clinically by testing and adjusting Free T3 and Free T4 as necessary to relieve symptoms.  symptom relief should be all important, not just test results.  You can get some good insight into clinical treatment from this letter written by a good thyroid doctor for patients that he sometimes consults with from a distance.  The letter is then sent to the PCP  of the patient to help guide treatment.


In the letter take note of the statement. "the ultimate criterion for dose adjustment must always be the clinical response of the patient."
Avatar universal
Excellent article .  Yes, that first doctor who did the study should have included Free T3 measurement as well .  Ironically, the guy is board certified endo but still could miss on this .

My question again is " can constipation be one of the  side effects of Synthroid " ?

Avatar universal
Absolutely yes.
Have an Answer?
Top Thyroid Answerers
649848 tn?1534637300
Avatar universal
1756321 tn?1547098925
Queensland, Australia
Learn About Top Answerers
Didn't find the answer you were looking for?
Ask a question
Popular Resources
We tapped the CDC for information on what you need to know about radiation exposure
Endocrinologist Mark Lupo, MD, answers 10 questions about thyroid disorders and how to treat them
A list of national and international resources and hotlines to help connect you to needed health and medical services.
Here’s how your baby’s growing in your body each week.
These common ADD/ADHD myths could already be hurting your child
This article will tell you more about strength training at home, giving you some options that require little to no equipment.