Which manufacturer?

Hello everyone. Following my post 4 days ago ‘Chemist prescribed incorrect dose’ I have now had my telephone conversation with my GP who has reduced my dosage to 75mg. (just as you thought clutter :-) ) My GP explained that levo is prescribed in 25mg 50mg and 100mg but not 75mg. I asked if there would be any benefit by taking 50mg in the morning and 25mg in the evening and he said none whatsoever and in fact you can take your thyroxine all in one go, once a week because it has a half life. I asked why it isn’t prescribed in this way and he said because people would forget to take it. Has anyone else heard this and/or medicate in this way?

Having said that there is another question I hope you can help with. When I started on Levo 50mg in Sept 2015 the tablets were manufactured by Mercurypharma, I subsequently received my repeat prescription at the incorrect dose of 100mg and this time the manufacturer was Actavis. Now that I am on 75mg, I collected my prescription of 25mg today to find this is made by Wockhardt so from tomorrow I shall be taking 50mg of Actavis and 25mg of Wockhardt. When I brought this to the chemist’s attention she said there is no difference between the three makes as they all have the same active ingredient (which they don't, see below). I said I wasn’t happy to have two different manufacturers but she said they have no control over what they are sent and any concern I have is all in the mind (excuse me!). I know from other medications that brands differ in quality and so my questions are this; Is there a preferred Levothyroxine manufacturer and is it ok to mix these. Just for info I have provided the ingredients for each of the manufacturers and thank you again for all your support.

Wockhardt = 27.8 levothyroxine sodium equivalent to 25 micrograms of anhydrous levothyroxine, lactose, sucrose, maize starch, magnesium sterate.

Actavis = 50mg anhydrous levothyroxine sodium, lactose, magnesium state, maize starch, stearic acid, pregelatinised maize starch.

MercuryPhama = anhydrous levothyroxine sodium, sodium citrate, lactose, maize starch, acacia powder, magnesium stearate.

14 Replies

I disagree with the chemist in that I believe she is stating that the hormone levothyroxine is the same - but the fillers/binders in the individual makes can affect us.

That's why it is recommended to ensure you get the same make each time in case different ones, particularly when we are trying to get to a dose which is compatible with our body, may have a bad effect and we wont know which one.

Thank you Shaw. That is exactly what I said to her. She was rather defensive, I guess in part because she was embarrassed prescribing the incorrect dose (although she may have done me a favour I the linger term) regardless, if I'm expected to take a concoction of types then I won't know which one is causing problems. I feel better but not great and yet to work out whether it's due to my body being messed up with incorrect dose or a reaction. Boy it's a long process, I thank you for your comments.

Some people do find they do better on one particular brand rather than another and most likely because of the fillers. Mercury Pharma has two ingredients that the others do not so that could be the cause of problems for some people.

I believe that the 25mcg tablets are only available from Wockhardt so there's no choice there other than to take 100mcg one day and 50mcg the next and continue to alternate to average 75mcg. I used to alternate 200 with 150 when I was on 175mcg rather than mess around with three strengths and different brands.

I used to be on Eltroxin, named on my prescription by my GP, and when that brand disappeared the pharmacist substituted with Actavis then asked me if I got on OK with it. When I said that I did he made sure that it was noted at the pharmacy that I was to be given Actavis every time and I've had that brand ever since.

As far as splitting your dose is concerned, you could try and see if it makes a difference. We are all different and one size doesn't fit all. I take my Levo at bedtime but not because I feel better for it but because I find it more convenient because of timing where supplements are concerned.

I have heard that it's possible to take Levo once a week but don't know anyone who does.

Thank you SS that is most helpful. Weird only wockhardt make 25. I guess my choices are Wockhardt or Acacia and split a 50. Thanks


I believe that the difference between anhydrous levothyroxine sodium and levothyroxine sodium is that the second form has a little water in its crystal structure.

In the making of tablets, it is common to mix the ingredients to a paste with water. Then form the tablets and dry them out. Whether the original ingredient was anhydrous or not seems (to me) to make little or no difference - once it is mixed with water it will no longer be anhydrous!

Further, it is difficult to control precisely the hydration of a substance like levothyroxine sodium. Open a jar of it, and it might absorb or lose water to the ambient atmosphere.

The reason that there is such dedicated attention to the use of the wording "anhydrous levothyroxine sodium" is because the official statement of potency is based on anhydrous levothyroxine sodium. (There was a case a few years ago where, I believe, a manufacturer used 25 micrograms of non-anhydrous levothyroxine sodium. Thus it was a few percent sub-potent. That product is no longer available. That case prompted a "make sure you are doing it right" notice to be issued.)

Details of thyroid hormone products are available here:


Thank you Helvella, I am learning so much from you all, I like the finer details and understand your comments. Thanks again,

Clarksons, your GP is right that Levothyroxine can be taken once weekly. Patients have been asked to take a weekly dose in front of their GP when they are suspected of non-compliance with daily dosing. He's also right that it is easier to remember to take a regular daily dose than one dose a week. Having said that, most people have mobile phones which mean you can set weekly alarms to remind you.

Your pharmacist is wrong to say all 3 brands of Levothyroxine are the same. They contain the same amount of active ingredient per dose but the fillers are different and this may affect patients tolerance and wellbeing. Mercury Pharma made me unwell but I'm fine on Actavis and Wockhardt and my pharmacist knows I won't accept MP. If your pharmacist won't order your preferred brand ask for your prescription to be returned and tell your pharmacist you will take it elsewhere to be filled.

Wockhardt has less fillers than Mercury Pharma and Actavis so will usually be acceptable. If not, and Actavis is your preferred brand, you'll have to ask your GP to prescribe 2 x 50mcg Actavis and cut one of the tablets in half to get the 75mcg dose. The danger with specifying a brand on prescription is that if Actavis becomes unavailable the pharmacy will be unable to dispense MP or Wockhardt until you present a new prescription not specifying brand.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

Thank you Clutter I think I've made a decision based on everyone's comments. I will go back tomorrow and exchange the Acacia for Wockhardt and monitor myself over the next 6weeks. Hopefully things will start to settle down now. Thank you all, so very much, Jacqui

Clarksons, my pharmacy won't accept medication back for exchange once it's left the shop.

Ooo! they owe me for over medicating me! Will that swing it: -)

Clarksons, not of itself but if they're feeling obliging they may exchange :)

this is something that I have been seriously concerned about for some time ...... the fillers [ that are fine normally ] that are used can have serious effects on some people --- just think if a filler was made from peanuts --- with the effects that we now know that some people have , not to say gluton,wheat, etc. ..... all of these fillers need to be taken into account because the active ingredient in carbim/levo may help in 1 way but the filler/s could create problems in other areas which would not be picked up and make the patient even worse and assumed to be from the original [ hyper/hypo ] condition ---- and then treatment for that would be wrong ....... just my thoughts on this ......alan

Thankyou AlanGardner. That is a worrying thought. Hope not hazelnut as I'm seriously allergic which is an off shoot of cross pollination of birch trees. Mmmm.

Ask your GP for an extra prescription explaining why you need it. Halve one 50mcg tablet and that will give you one 50mcg plus half tablet = 75mcg.

Let them think you're being fussy but it is you who has to cope not knowing which one 'might' be a problem.

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