Is there actually a difference between synthroi... - Thyroid UK

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Is there actually a difference between synthroid and generic?

Angie10116 profile image
32 Replies

I’m very curious to hear if people actually feel better on synthroid over generic Levo ( accord, teva ect)? If so, why? Are there different ingredients involved?

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Angie10116
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SlowDragon profile image
SlowDragonAdministrator

Here in U.K. we can’t get synthroid

Many people find Levothyroxine brands are not interchangeable. They have different fillers

Also they aren’t bio equivalent

100mcg of one brand will give different results compared to 100mcg of another brand

Many patients do NOT get on well with Teva brand of Levothyroxine.

Teva contains mannitol as a filler, which seems to be possible cause of problems. Teva is the only brand that makes 75mcg tablet. So if avoiding Teva for 75mcg dose ask for 25mcg to add to 50mcg or just extra 50mcg tablets to cut in half

But for some people (usually if lactose intolerant, Teva is by far the best option)

Teva, or Aristo (100mcg only) are the only lactose free tablets

Most easily available (and often most easily tolerated) are Mercury Pharma or Accord

Mercury Pharma make 25mcg, 50mcg and 100mcg tablets

Accord is also boxed as Almus via Boots, and Northstar 50mcg and 100mcg via Lloyds ....but Accord doesn’t make 25mcg tablets

beware 25mcg Northstar is Teva

List of different brands available in U.K.

thyroiduk.org/if-you-are-hy...

Posts that mention Teva

healthunlocked.com/search/p...

Teva poll

healthunlocked.com/thyroidu...

Once you find a brand that suits you, best to make sure to only get that one at each prescription.

Watch out for brand change when dose is increased or at repeat prescription.

New guidelines for GP if you find it difficult/impossible to change brands

gov.uk/drug-safety-update/l...

If a patient reports persistent symptoms when switching between different levothyroxine tablet formulations, consider consistently prescribing a specific product known to be well tolerated by the patient. If symptoms or poor control of thyroid function persist (despite adhering to a specific product), consider prescribing levothyroxine in an oral solution formulation.

healthunlocked.com/thyroidu...

academic.oup.com/jcem/artic...

Physicians should: 1) alert patients that preparations may be switched at the pharmacy; 2) encourage patients to ask to remain on the same preparation at every pharmacy refill; and 3) make sure patients understand the need to have their TSH retested and the potential for dosing readjusted every time their LT4 preparation is switched (18).

Levothyroxine is an extremely fussy hormone and should always be taken on an empty stomach and then nothing apart from water for at least an hour after

Many people take Levothyroxine soon after waking, but it may be more convenient and perhaps more effective taken at bedtime

verywellhealth.com/best-tim...

No other medication or supplements at same as Levothyroxine, leave at least 2 hour gap.

Some like iron, calcium, magnesium, HRT, omeprazole or vitamin D should be four hours away

(Time gap doesn't apply to Vitamin D mouth spray)

If you normally take levothyroxine at bedtime/in night ...adjust timings as follows prior to blood test

If testing Monday morning, delay Saturday evening dose levothyroxine until Sunday morning. Delay Sunday evening dose levothyroxine until after blood test on Monday morning. Take Monday evening dose levothyroxine as per normal

REMEMBER.....very important....stop taking any supplements that contain biotin a week before ALL BLOOD TESTS as biotin can falsely affect test results - eg vitamin B complex

Angie10116 profile image
Angie10116 in reply toSlowDragon

Thanks for your answer!

Accord crumbles so easy for me so I need 75mg. I guess I’ll have to try teva again!

Synthroid is available privately if I’m correct? I’m still wondering what the differences are between generic and synthroid.

SlowDragon profile image
SlowDragonAdministrator in reply toAngie10116

Mercury Pharma make 25mcg

Accord is easy to cut with pill cutter or sharp craft scalpel

Or take 50mcg and 100mcg tablets alternate days to give 75mcg daily

75mcg is only one step up from starter dose, unless extremely petite, probably not high enough dose anyway

Not aware of any one in U.K. getting synthroid (it’s USA based )

Angie10116 profile image
Angie10116 in reply toSlowDragon

Yeah 75 is low but I just wanted to give my body time to adjust…. In the last 12 weeks I’ve been on 50mg, 100mg, 150 mg, back to 50mg and now on 75… my doctors kinda messed me up

SlowDragon profile image
SlowDragonAdministrator in reply toAngie10116

Yes, having seen previous posts…..I would agree

Slow and steady

Retest after 6-8 weeks on 75mcg

(or wait a bit longer 8-12 weeks before testing)

Angie10116 profile image
Angie10116 in reply toSlowDragon

Could I ask for some reassurance about my symptoms? I’m sorry, I know that I keep asking lots of questions but you all are so knowledgeable and I can’t rely on doctors here. My symptoms are mainly mental changes. Extreme brain fog, almost seeing everything as though I was tipsy, mad memory, depression, anxiety, confused and just quite dumb. I’ve always been sharp and quick, but it takes me to long to understand things now in a simple conversation. My brain just goes blank. I know that as my thyroid levels are optimum, I should start to feel better. But I’m scared that I’ll never feel like I’m back to reality.

SlowDragon profile image
SlowDragonAdministrator in reply toAngie10116

Yes, brain fog is common ……it does get better

Your brain needs lots of Ft3

You will start feeling better, especially now you have found this forum

Slow steady dose change, getting vitamins optimal

And testing TSH, Ft4 and Ft3

Come back with new post once you get results after being on 75mcg 6-8 weeks minimum

Angie10116 profile image
Angie10116 in reply toSlowDragon

Thank you. It’s easy to be negative when feeling so weird!

helvella profile image
helvellaAdministrator in reply toAngie10116

There is currently a recall because Accord (specially packaged as Northstar) 50 microgram tablets crumble too much.

If you think your Accord is too crumbly, consider putting in a Yellow Card report.

Angie10116 profile image
Angie10116 in reply tohelvella

Yeah that’s what’s going on with mine. I’ll try to cut them up as suggested above. I didn’t know that alternating days like that is allowed?

helvella profile image
helvellaAdministrator in reply toAngie10116

It is allowed and many do it. But some prefer same dose every day. I am one of those who much prefer same dose and I have tried several times to alternate doses.

Angie10116 profile image
Angie10116 in reply tohelvella

I asume it’s much easier to keep track of everything if it’s the same dose daily. I tried to give back the accord 50s that crumble, but the pharmacy only stocks that brand and they won’t change it for me. So I guess I’ll have to try 100mg one day and 50mg the other

helvella profile image
helvellaAdministrator in reply toAngie10116

Or ask for a new prescription - I suggest 50 and 25. (Accord do not make a 25 microgram tablet but others do.)

Angie10116 profile image
Angie10116 in reply tohelvella

Thank you. Is it okay to mix brands ?

helvella profile image
helvellaAdministrator in reply toAngie10116

Yes and no.

If you do OK on mixed tablets, it is fine.

If you have a problem, it can be slightly more difficult to identify which tablet is the issue!

And if you get Mercury Pharma or Teva, they do make 25 and 50 tablets.

Angie10116 profile image
Angie10116 in reply tohelvella

Thank you! I’ll see what I can get from the doctors tomorrow

Yesletsgo profile image
Yesletsgo in reply toAngie10116

Brain fog is horrible. Try taking a multivitamin with iron, I started this (only last week) after reading some posts on here about the importance of having the right levels especially of iron and vitamin D and it really seems to have made a difference. Can't believe I may have been suffering unnecessarily for so long.

Angie10116 profile image
Angie10116 in reply toYesletsgo

I’m so glad it’s been helping you! My ferritin was 41 ( range 15-300). Doctors said it’s fine but I’ve decided to supplement iron. I also started a few other ones, so hopefully they will help also.

May I ask you to describe your brain fog? How has it affected you? I can’t drive because I just feel drunk lol

Yesletsgo profile image
Yesletsgo in reply toAngie10116

Oh, the brain fog! Not being able to follow a train of thought. Not being able to follow a radio broadcast without zoning out. Going into a room to do something and forgetting it over and over, to the extent I worry it may be dementia. Starting to speak a sentence and the wrong words coming out. Energy dropping to zero when I should be at peak fitness. The only plus is I do stay awake most of the time! Before I was diagnosed I would often think I was going to fall asleep at the wheel and I know I did at least once. Thankfully that doesn't seem to happen any more (I take breaks more often).

Angie10116 profile image
Angie10116 in reply toYesletsgo

I’m so sorry that we have to feel that way! It’s made the world look almost unrealistic to me. It’s so strange! So yours is getting better?

Yesletsgo profile image
Yesletsgo in reply toAngie10116

Brain fog is just so horrible. Thankfully since I started the multivitamins about a week or so ago I'm feeling more like myself. I'd always thought I didn't need them because I eat a fairly healthy balanced diet but they've definitely made a difference 😁

Angie10116 profile image
Angie10116 in reply toYesletsgo

I’m so glad that they’re helping you! Wishing you all of the best lovely! ❤️

humanbean profile image
humanbean

The difference between makes or brands of Levo is the name on the box, the marketing budget, and the fillers/excipients. The active ingredient will always be the same.

If a box says that the pills inside contain 100mcg of Levothyroxine, then there is a tiny amount of leeway given to manufacturers and they must produce pills with an active ingredient within 95% - 105% of the stated dose. (I could be out of date - or wrong - with those numbers.)

Excipients and fillers are the things in a pill that are added to the active ingredient to turn it into a pill big enough to hold and put into a blister pack.

Excipients and fillers that are well known for causing problems for some patients are acacia, mannitol, gluten and lactose (milk sugar). No doubt there are others I don't know about.

In recent years a French brand of Levo changed the lactose in their Levo pills for mannitol. Lots of people couldn't tolerate it and there were actually demonstrations about it in France.

All Uk medications have to be gluten-free, but I don't know if that is true in other countries.

This might be just an online myth...

I have read about Synthroid that the manufacturers aim to achieve a higher level of levothyroxine in their pills than they really need to i.e. about 100% - 105% of the stated dose, rather than the required 95% - 105%. People complain that they feel worse if they are switched to a different brand.

Living in the UK as I do, where all Levo is considered to be generic, Synthroid isn't available, and drugs aren't advertised, I think a lot of the "Synthroid is special" hype is due to marketing.

But it is true that pills may be different because the amounts and types of excipients in the pills could be different. We always suggest that people should try one make of Levo, keep records of what we are taking, what tablet sizes we are taking etc, note symptoms on each make. Then switch to another make, do the same record-keeping, then switch to a third make etc. I don't remember how many makes of Levothyroxine there are in the UK - but I know it isn't many.

Also be aware, in both the US and the UK that manufacturers can sell their pills to a particular chain of pharmacies who then change the box and the name of the pills to their own branding and their own choice of name. In the UK, to know for certain who made our pills, you have to check the blister pack not the cardboard box. This might be true in the US as well.

For more info on the ingredients of prescribed hormones and drugs in the USA see this website :

dailymed.nlm.nih.gov/dailymed/

helvella profile image
helvellaAdministrator in reply tohumanbean

The tolerance for levothyroxine in the USA is 95 to 105%. In the UK it is 90 to 105%.

Putting in too much active ingredient is called "overage". It is now banned in the USA, EU and UK. The manufacturers must target 100% throughout the manufacturing process.

Yes, I do believe that intentional overage is one reason people often wished to return to Synthroid if switched to another product.

The manufacturer is ALSO on the box. See attached image.

Merck changed levothyroxine in France over to mannitol, and now say they have done so in 18 countries - probably most of the EU.

All UK products are listed in my document!

helvella - Thyroid Hormone Medicines

I have created, and try to maintain, a document containing details of all thyroid hormone medicines in the UK and, in less detail, many others around the world.

dropbox.com/s/shcwdwpedzr93...

Almus levothyroxine card outer
humanbean profile image
humanbean in reply tohelvella

Merck changed levothyroxine in France over to mannitol, and now say they have done so in 18 countries - probably most of the EU.

I heard or read that bringing back the old formula was only going to happen for a short time. I wasn't aware that they had continued their plan of putting mannitol in pills pretty much everywhere.

Do you know why they changed over to Mannitol? I never saw an explanation for that.

helvella profile image
helvellaAdministrator in reply tohumanbean

You can read a post I recently did - which sometimes reads as if it was done by Merck's PR department:

healthunlocked.com/thyroidu...

A main issue is the Maillard reactions between lactose and levothyroxine.

Irroincally, you and I will probably most like have come across Maillard reactions watching Masterchef or similar! They are the protein/sugar reactions which cause browning.

humanbean profile image
humanbean in reply tohelvella

The Merck paper had a few bits in at the start that rubbed me up the wrong way. For example (the text in bold) :

The current guideline-driven management of hypothyroidism is based on thyroid hormone replacement with levothyroxine (LT4), with the dosage titrated to maintain thyrotropin (TSH; thyroid stimulating hormone) within a defined euthyroid reference range.1,2

In my opinion, and the opinions of many other patients, the most important factor in thyroid-related wellness is the Free T3 level. The least important is TSH.

The homeostatic regulation of thyroid function is such that small differences in the circulating level of thyroxine (T4) cause much larger (as much as ten-fold) and opposite changes in the level of TSH.

The reference to 10-fold differences in TSH has never been true for me, nor have I seen evidence it is true for other members who have quoted results before and after changes in dose. Perhaps my problem is that I pay almost zero attention to TSH.

I notice it doesn't actually mention demonstrations in France, which I suppose isn't that surprising. And regarding the global search for ICSRs (Individual Case Safety Reports), if all the affected patients complained to their doctors then many of them were probably told the problem was all in their heads and they were just gaslighted and sent on their way.

helvella profile image
helvellaAdministrator in reply tohumanbean

Agreed. Many times over.

Many papers refer to a logarithmic relationship, which is questionable. But a simple multiplication is absolutely wrong.

When I say, yet again, put in a Yellow Card report, I really don't think those who I am replying to appreciate that these reports can filter into papers like this.

I implore everyone to put in Yellow Card reports.

humanbean profile image
humanbean in reply tohelvella

Saying that the name of the maker is on the box as well as the blister pack...

For that Almus box you've pictured I'm assuming the pills were made by Actavis? i.e. the product license (PL) holder?

helvella profile image
helvellaAdministrator in reply tohumanbean

Sorry - I didn't make that clear.

Yes - might say MAH or PL - that is the company that obtained the licence (manufacturing authority) and is responsible thoughout - even if the "brand" is Almus.

If I had taken a new photo, it would say "Accord" there.

This is my own experience: it´s not only about brand levothyroxine vs generics, but also about fillers in individual brands.Where I live, only two brands of thyroxine are available: Euthyrox by Merck and L-Thyroxine by Takeda. Both have been reformulated in recent years. Takeda´s product was reformulated in 2015 and Euthyrox in 2018. The latter now contains mannitol (just like the UK brand Teva). Nobody knows exactly how Takeda´s product was reformulated; the manufacturer just sent a note to doctors a few months in advance to inform them that the new version would be approximately 33% more potent so that dosages should be adjusted accordingly.

From what I know - from various patient forums - some people reacted horribly to the reformulated Euthyrox and had to switch to L-Thyroxine by Takeda. Some did ok on it, others didn´t. So, some patients are now on the German brand Henning which they order from German pharmacies with a doctor´s prescription.

So, mannitol as a filler seems to be problematic for some.

Every time a drug is reformulated, it seems to have implications for patients. Manufacturers tend to claim that only the active ingredient - levothyroxine - is important, and that fillers are not.

Personally, I have never understood why they put common allergens, such as cornstarch, in thyroid pills...or lactose - known to inhibit the absorption of said hormones...

Angie10116 profile image
Angie10116 in reply to

Thanks for the in-depth comment! They seem to make their job so much harder by adding in all those horrible ingredients. It’s good that there are so many options for patients at least!

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