Gluten and Aluminum Content in Synthroid® (Levo... - Thyroid UK

Thyroid UK

113,199 members131,511 posts

Gluten and Aluminum Content in Synthroid® (Levothyroxine Sodium Tablets)


Before reading another word - look at the funding!

The paper defies logic - they claim the maximum dose of aluminium from a tablet is 137 micrograms - which is way below the FDA-determined minimal risk level. Which in itself might provide some reassurance. It totally ignores the possibility of the patient taking two or more tablets! It also ignores that this 137n micrograms is IN ADDITION to any other sources of aluminium.

In the end, my main reason for posting is to highlight that AbbVie felt there was reason to do this research and publish the summary of results. Looks to me as if they are reacting to patients who are questioning both gluten and aluminium content of Synthroid. (Would have been far more useful if they had done the research across the market, even if just the USA market. Not just their own. Perhaps they found every other make had less aluminium and so didn't publish those results!)

Adv Ther. 2017 Jun 26. doi: 10.1007/s12325-017-0575-y. [Epub ahead of print]

Gluten and Aluminum Content in Synthroid® (Levothyroxine Sodium Tablets).

Espaillat R1, Jarvis MF2, Torkelson C2, Sinclair B2.

Author information

1 AbbVie Inc., North Chicago, IL, USA.

2 AbbVie Inc., North Chicago, IL, USA.



Inquiries from healthcare providers and patients about the gluten and aluminum content of Synthroid® (levothyroxine sodium tablets) have increased. The objective of this study was to measure and evaluate the gluten content of the raw materials used in the manufacturing of Synthroid. Additionally, this study determined the aluminum content in different strengths of Synthroid tablets by estimating the amount of aluminum in the raw materials used in the manufacturing of Synthroid.


Gluten levels of three lots of the active pharmaceutical ingredient (API) and one lot of each excipient from different vendors were examined. The ingredients in all current Synthroid formulations (strengths) were evaluated for their quantity of aluminum.


Gluten concentrations were below the lowest limit of detection (<3.0 ppm) for all tested lots of the API and excipients of Synthroid tablets. Aluminum content varied across tablet strengths (range 19-137 µg/tablet). Gluten levels of the API and excipients were found to be below the lowest level of detection and are considered gluten-free based on the US Food and Drug Administration (FDA) definition for food products. Across the various tablet strengths of Synthroid, the maximum aluminum levels were well below the FDA-determined minimal risk level for chronic oral aluminum exposure (1 mg/kg/day).


These data demonstrate that Synthroid tablets are not a source for dietary gluten and are a minimal source of aluminum.



AbbVie Inc.



Aluminum; Chemical analysis; Endocrinology; Excipients; Gluten; Hypothyroidism; Levothyroxine; Synthroid

PMID: 28649691

DOI: 10.1007/s12325-017-0575-y

6 Replies

Interesting. Aluminium indeed is problematic same way that fluoride yet they have made it possible for us to take certain medication. Fortunately and unfortunately. Some meds one could never take if it weren't done with fluoride as it as well decrease the absorption rate or help the meds to enter the target cells. Aluminium I believe has similar qualities. I might be wrong about aluminium , but it is in Rennie as well which is for neutralising stomach acids. Rennie these days is advised not to take too often.

helvellaAdministrator in reply to Justiina

I was under the impression that most of the aluminium content was used as the colouring agent. (Unlike in the UK, all dosages except 50 micrograms are coloured.)

Justiina in reply to helvella

Maybe it's different form of aluminium that makes the difference? As if one suffers from bile acids which more harmful than normal gastric acid as bile acid burns the gut lining, but cause less symptoms (so it goes undetected for long) is treated with aluminium salt or at least was and therefore Rennie was efficient for bile acid, gaviscon was another one and that has or had aluminium too if I remember correct.

Should I be concerned about my UniPharma T3?

3 ppm is the lowest amount of gluten that they can physically test for so <3ppm could actually mean 0 gluten contained. Anything under 20ppm can be legally certified as gluten free in UK and many coeliacs are fine with this. It has to be less than 5ppm in australia to get GF listing. I am particularly sensitive and still can't eat anything considered legally gluten free if has any amount in - barley malt extract certified GF for example. I have never had gluten reaction to any thyroid meds although I think UK and europe is more stringent than the US in regards to what is considered Gluten free anyway so should be fine in that regards.

Aluminium however, is very interesting lol :-)

I'm certainly reacting to something in the levo that I've never experienced with T3 that I've been on for years only - just like a minor allergy or something bugging system??

TEVA really bugged my kidneys mind you and caused massive pain in this area and back and am yellow carding that one as shouldn't happen. I wont with the others though as only probably something I'm sensitive too which really isn't their fault.

Yes, my body certainly hates chemicals/unnatural substances etc so stay away as much as poss.

Not sure whether it is something in the T4 or T4 itself as have never had an issues on nearly 15 yrs T3 only. I've got one more brand to try which doesn't have sucrose/sweetners in and has same ingredients as my T3 so will give that a go - otherwise must be the levo lol!!

You may also like...