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Thyroid UK
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Why are my Hypothyroid symptoms worse when pre-menstrual? Do thyroid levels fluctuate throughout the month? How can I treat them?

Evening All!

I'm on 75mcg Levothyroxine and, as of a week ago, 5mcg Liothyronine from Tiromel (please see my previous posts for Bloods info).

So; I'm wondering if anyone is able to tell me why my fatigue - and specifically, my aches and pains - are worse in the week running up to my period?

Surely it can't be iron levels, because as soon as the bleeding starts (and my iron levels presumably drop), I feel better?

As part of post-viral ME/ CFS (20 years now) I have suffered from chronic pain, and it's so agonising in the run-up to my period that my mobility drops to the point of being disabled, and I can't sleep without Tramadol. I basically drop out of social circulation due to physical symptoms, even though emotionally I feel fine.

I even double my dose of anti-depressants for half the month on my GP's suggestion to help ease the excruciating aching, as it's a low-dose painkiller.

I've been on the Turkish T3 medication Tiromel for a week now (a quarter pill - 5mcg - in the morning), and it's proved an incredible help already. In fact I'm thrilled!

However, I haven't yet hit my monthly PMT week/ fortnight, and I'd love to know if there's anything I'm missing with regards to my thyroid regulation. I'm 41 but this agony has been going on for a couple of years.

In fact, it's because of my menses highlighting my thyroid issues that I first went to my GP a couple of years ago; I felt my thyroid and the horrendous PMT were related, and it wasn't my ME/ CFS. But I don't know how my hormones affect my thyroid! Can anyone explain the link?

And more importantly, is anyone able to suggest how to self-medicate during the lead-up to my period, in order to avoid the pain/ complete shut-down of my system? Please let me know your thoughts.

As well as Levothyroxine and Liothyronine I'm taking Ferrous Fumerate, Vit D3 and Vit B12.

I'm 41, but not perimenopausal as I've had the blood test through my GP and anyway, this has been going on for nearly two years

Heartfelt thanks in advance for your input,


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Thyroid hormone levels can affect the metabolism of female hormones and interfere with the regulation of ovarian function ..... either to do with the fluctuations of oestrogens and progesterone, or cortisol related, or to do with the sex hormone binding proteins grabbing thyroid hormone and disabling it from becoming active.

The HPA-Axis and HPT-Axis work in parallel and cortisol and TSH should correlate. All hormones are dependant on each other so any deficiency (or elevation) may have repercussions somewhere else up the line.

If you have Hashi, steroid hormones (including O & P) influence the development of immune cells and modulate the output of the immune system. Many immune cells have receptors for these hormones, including many of the immune cells responsible for creating autoimmunity. Sex hormones also activate some of specific genes that play a role in symptom flares. That is why many members find they become more Hashi symptomatic around their period time.

I used to have such a good link to show how Hashi interferes with every stage of the female cycle but it has gone. Now apparently you have buy the ****** book ! ! ....

You could have oestrogen, progesterone, follicle-stimulating hormone and luteinizing hormone levels (among others) tested at the different phases of your menstrual cycle ... so being able to evaluate whether your hormonal cycle is normal.

Have you got any thyroid hormone blood test results to post complete with ranges (numbers in brackets) for members comments ?


Arrr ... just looked at previous results.

No Hashi (lucky you) but you are undermedicated so might find things settle once everything optimises.

Also RT3 is high and can take a while to clear if you are medicating T4. Good previous advice from Clutter re dosing.

You may find it useful to have cortisol tested.


Aw, thanks so much for taking the time to reply. Both instances! :-)

So, should I continue to take the Liothyronine without increasing the Levothryoxine?

How do I know when to add in an afternoon Liothyronine dose?

How do I know when to increase the Levothyroxine?

And back on topic: in your knowledgable view, should I increase or decrease either every month in the week leading up to my period?

I'm absolutely poleaxed every month - genuinely disabled - so looking to decrease hormonal fallout and my life completely coming to a standstill whilst I cower crying in agony in a corner for days at a time (nothing to do with period cramps, and everything to do with thyroid-related muscle and joint pain!).

I feel I should be changing my dose for those ten days leading up to my period (they're regular as clockwork, which helps).

The rest of the month I'm on 75mcg Levothryoxine and (currently) 5mcg Liothyronine.

Any thoughts/ tips?

Thanks again, so so much for your detailed reponse. I'm learning loads! πŸ˜ƒ



Thyroid hormone replacement should be taken consistently as your body needs a constant supply … especially as T3 has a short half life.

The high RT3 could be preventing T3 from doing it's job so making you symptomatic. T3 will help to clear RT3 but should be added slowly. Leave at 5mcg for a week and if all is well, add another 5mcg.

Symptoms of intolerance might include sweating & inner heat or palpitations. Add a further 5mcg after another week and a final 5mcg after another week …. so totalling 20mcg T3 altogether. Do not feel the need to rush this stage as it takes time for a T3 depleted body to accept it again. Also as RT3 is detoxified, it can make you feel unwell.

Leave Levothyroxine at 75mcg as with high RT3 you don't want to increase T4 and shouldn't need to anyway as adding the extra T3 will be the equivalent to 135mcg T4 in total .

Many members split their T3 dose between two to three times a day in order to reduce the rapidity of onset and prolong the duration of it's action. T3 may be taken with your dose of T4.

You will need to retest thyroid hormones (including FT3) after six weeks of final adjustment & post results complete with ranges (numbers in brackets).

Hopefully you will begin to feel better as your T3 levels raise.

Are you addressing other deficiencies ?


Many thanks you wonderful Angel πŸ˜‡ and yes, happily other vitamin and mineral imbalances are already being addressed.

I was just wondering - if there was a natural monthly imbalance - whether I should and could address it myself.

Already feeling better on Liothyronine: one week in and I almost cried this morning I felt so much better (as opposed to last Sunday, when I was non PMT-y but still so ill with thyroid issues that I had a little cry to myself before hobbling to meet my husband and kids at a friend's garden party). It's amazing what a week can do!

Was going to wait a fortnight before adding a second dose of Liothyronine, but if you think waiting one week's OK I may try adding more tomorrow (I started on it last Tuesday).

Don't want to push it, but I couldn't be happier with the results so far!



I'm intrigued. I also have Hashimoto's and prolonged, bad PMT symptoms. I've been like this for years. What book are you referring to? Thanks



This is my link that previously explained the effects of Hashimotos on a woman's cycle.

I have not bought this book and do not know if it even contains the said explanations.

I suffered menorrhagia for years until optimally medicated on thyroid hormones, by which time I was well into my menopause.





Like yourself I also suffer from heavy periods but I'm hoping once I'm on an "optimal" dose of dessicated thyroid that will change. It seems hard to believe but I'm waiting in hope.

As you said earlier you have to buy the book to access the articles on that website. Still good to have the link. Thanks anyway.


You say you are taking vitamin D, B12 and ferrous fumerate, but have you got recent tests results for these.

How much vitamin D are you taking? Are you also taking magnesium and vitamin K2. Magnesium is important cofactor of vitamin D and our need for magnesium increases when supplementing vitamin D


B12, when supplementing its recommended we take vitamin B complex as well.

But you must remember to stop taking any supplements with biotin in before any future blood tests as biotin can falsely affect test results



Ooh, thanks for this.

Didn't know about Magnesium or K2.

Have B complex and B12.

Haven't had tests more recently than last month as only just started on supplement protocol.

Thank you for Biotin info x


Hello Abi-Abster. I have a suggestion for you, shown to be effective in clinical trials. Yoga, whole yoga, not the gym-type but very eastern including importantly making sounds and both breathing and pranayama, has been shown to maintain GABA levels so that they don't drop pre-menstrually. Although there is as yet no proof that GABA levels affect PMT etc and depression, both definitely respond and improve when GABA levels are maintained, there is assumed to be a causal link.

There's quite a bit of information about GABA on my yoga website, if you'd like to read it I'll send you the website address.

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You're gorgeous. Yes please.

Most serendipitous: After twenty years practise, I'm actually finally training to be a yoga teacher! Would love to see your website. Thank you :-)

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Serendipitous indeed! The website is pennyjollyyoga@hotmail.co.uk and the bit about GABA is on the page called, I think, Healing Yoga. Who are you training with? If BWY there's a chance we might bump into each other doing CPD. I'm on the Gloucestershire/Herefordshire border but pend time in the New Forest and travel to good yoga training events (like Yoga Biomedical Trust retreats). Yoga Biomedical Trust gets excellent Indian teachers, usually fully qualified medical doctors as well over to the UK to teach or speak at seminars. The GABA info comes from the - Minded Institute but you have to watch out, they rather over-egg the pudding! Now you'll say that's who you are training with!!!


Oops! You gave me your email address by mistake, but I managed to find your lovely website and it looks fab. As do you!

Wish I'd been training with BWY - meant to start with them a decade ago but kids and ME/ CFS got in the way.

For ease of travel/ pain/ illness I'm studying with Unity Yoga in Brighton (where I live) which is part of the IYN.

I'll have a look at your GABA Healing Yoga page now!


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