I am currently trying to work through some ideas regarding lactose and levothyroxine.
As I see it, many people who have never in their lives had any problem with lactose seem unable to tolerate lactose in levothyroxine tablets.
This is wholly my speculation and could be completely wrong-headed. But I would appreciate if anyone would have a look at my summary notes - even look up some of the papers referenced, and let me know where I am going wrong.
I am not sure if I am misunderstanding this but are you saying we need lactose and Levo reduces the production of the enzyme and this affects people with hypothyroidism?
I think the combination of being hypothyroid AND taking levothyroxine reduces our ability to make the enzyme lactase properly and in sufficient quantity.
If we do not have sufficient lactase enzyme, we cannot digest lactose (the sugar). Therefore, we suffer from the same issues as anyone else who is lactose-intolerant. And that includes both impaired absorption of levothyroxine and digestion issues.
The NHS has a brief description of lactose intolerance where they explain that:
Some people may still be able to drink a small glass of milk without triggering any symptoms, while others may not even be able to have milk in their tea or coffee.
nhs.uk/conditions/lactose-i...
I suspect that hypothyroid AND taking levothyroxine moves us in the direction from being able to drink a small glass of milk towards not being able to have milk in tea and coffee. And, specifically, being upset by the lactose in many levothyroxine tablets.
Definite changes with Levo and food products generally. I have come to a view that the levo in some way becomes associated with food proteins by mistake. Turns out that I have autoimmune Hashimoto's, at one point I started eating after taking my Levo as nothing was making me feel better. When I was allergy tested; all the foods that I ate for that 2 weeks , in the morning; became allergens for me. Whether the Hashimoto's also sees Levothyroxine as an invader too, as well as Thyroid Gland. Anyway, that is my Two Pennith. Good luck with the research.
Ok yes I understand now thank you.
I’m so glad youve looked at this! Because I have been absolutely baffled why my throat started swelling with Gluten and Dairy after I started on Levo when I never had any problems before and further developed Eosinophillic Oesophagitis. I’m now on NDT but its the same reaction to Gluten and Dairy. I find LDN the only thing that helps. So pleased to understand it better! Thank you helvella x
Do remember - this is just guesswork by someone who has not trained as a biochemist! 
It makes sense to me! x
Helvella its red wine as well for me that I struggle to tolerate now - Gluten, Dairy and red wine! How does that fit in with your theory? I am prescribed Budesonide steroid for topical application to my throat morning and night and it does nothing. Why does LDN make such a difference? Would that fit in with your theory?
I do think youre on to something x
Red wine gives me a headache so I can only drink white or a rosé wine.
Not at all!
I have no idea why red wine would be affected by anything I have thought about. At least, not why red as opposed to white.
Afraid I am one of the lucky ones - I can (and do) eat gluten, dairy and drink red wine!
I dont really drink white so I wouldnt know. But I do think youre on to something because I had no problems eating or drinking anything until a few months after starting Levo.
I was better with the Teva lactose free brand too x
It is the number of people who have said things like that which has pushed me to see what I can find out. And try to string together.
I might Yellow Card it! - that Levo has caused me to be intolerant of certain foods (I have Yellow Carded that Levo caused me Esinophillic Oesophagitis) x
have you tried organic red wine? Aldi? I'm fine with that !
Autoimmune issue if the LDN helps. Does antihistamine also help?
Consider yourself as having passed your first Exam helvella . Thank you for this post.
what is LDN ? I now avoid all dairy - I miss yoghurt for breakfast mostly - I occasionally have an ice cream- but mostly coconut now
LDN = Low Dose Naltrexone
Abbreviations and Acronyms
Some years ago, I started compiling a list of many of the abbreviations and acronyms that appear on the Thyroid UK forum ( healthunlocked.com/thyroiduk/ ) regularly. The idea was to make it relatively quick and easy to look up abbreviations and acronyms without being waylaid by the many irrelevant possibilities that web searches tend to return.
I continue to update the document quite frequently!
dropbox.com/s/2423slilh0or6...
You might never have downloaded a copy, or not for some time, perhaps months or years If so, I suggest you download a copy and save it (or a shortcut) somewhere easy to find.
Please, if you think there is anything missing or wrong, let me know. Post on the forum or send me a Private Message.
If I have posted this because you asked about, or referred to, an abbreviation or acronym, please take this as intended, a way of helping you now and into the future. Not a criticism that you asked.
Thank you !! Now googling that ! 😜
There are at least 148 posts on this forum which mention naltrexone!
I too, will be very happy to understand this. Drunk gallons of milk all my life until, taking Levo, for about a year; then all hell broke loose in the area of food. Just started LND myself, out of desperation. Would love to know the answer to this puzzle.....with me it is not the Lactose but the "thingy" protein in diary ( excuse my memory)
Casein?
So it might be worth me experimenting with supplementing stomach enzymes to test out your theory x
Also helvella my father was born with Lactase intolerance which he suposedly grew out of. I suspect he was hypothyroid and had Sjogrens Syndrome as I have also developed. Laterly he developed Parkinsons too. Maybe I have an inherited genetic fault that is further impeded by Levo and you do not x
I wondered why my 23&me test did not find lactose intolerance, & other specific lab work was negative for it. Yet lactose now gives me gas big time. I take Synthroid & Tirosint however. I think you are on to something.
It's all very intriguing Helvella. I was diagnosed intolerant to wheat, eggs, chicken etc 6 years before being diagnosed hypothyroid and carefully avoided those foods but did eat pumpernickel or rye bread that didn't contain wheat.
5 years after my hypo diagnosis I developed Hashi's and very fortunately found TUK and this site. I then avoided all gluten. About a year later I avoided all dairy and had further improvement.
I now always use lactose free milk in my tea and coffee and always only use lactose free cream. However, I do eat normal cheddar and organic yoghurt. I definitely get griping stomach pains if I inadvertently use normal milk (hubby's) in my drinks. My daughter in recent years cannot tolerate any dairy at all and my grand daughter is coeliac, so there must be some genetic element.
At least these days it is so much easier to follow gluten and dairy free diet. The egg issue is still bad for me and of course a lot of GF foods contain egg to compensate for lack of gluten. I've learned to live without those foods. My life is almost normal these days and the addition of 15mcgm lio to my 100 mcgm levo has also made a difference.
I shall await with interest the outcome of your research. Keep up the good work.
A very interesting read. I was taking levo for very many years with zero lactose issues, had a constitution like a horse as the saying goes .
Succumbed to hiatus hernia and Barrett’s oesophagus, had to cut back on alcohol a bit. Loved red wine so a bit sad. However I now cope with the odd glass again. 🙂
I may be wrong - But doesn't it say on the leaflet instructions to avoid taking your levothyroxine with your morning tea & milk? Long time since I stopped mine & went to NDT but I'm sure I've read that? Could be Casein or Lactose maybe?
Lactose Free Levothyroxine 
Lactose
Lactose-free Levothyroxine?
Do you take lactose-free Levothyroxine oral solution? 
Lactose and mannitol free levothyroxine brands?
