How can I tell if I need another levothyroxine dosage increase?

[melissa-b]

Hi guys, I'm back again... After going up on my dosage in August, I initially felt anxious and headachy, but then started to feel a lot better. My skin cleared up, I had more energy, and my weekly migraines completely stopped (!) until December.

Now I'm completely exhausted again, skin breaking out, joint pain, hair thinning, and my weekly migraines are back. I've also had some strange heart symptoms since December, which I THINK are PVCs and PACs (waiting on results of Holter monitor), and I've had a lot of muscle twitching.

But my levels aren't necessarily showing this:

15 Aug 2024:

Serum TSH level 6.73 mIU/L [0.38 - 5.33] Abnormal

Serum free T4 level 12.4 pmol/L [8.0 - 18.0] Normal

17 Aug 2024:

Started 75mg Levothyroxine

6 Nov 2024:

Serum TSH level 5.04 mIU/L [0.38 - 5.33] Normal

Serum free T4 level 14.2 pmol/L [8.0 - 18.0] Normal

Serum free T3 level 5.3 pmol/L [3.8 - 6.0] Normal

31 Jan 2025:

Serum TSH level 3.99 mIU/L [0.38 - 5.33] Normal

I also had an ultrasound on my thyroid in November, and they found nothing at all (no swelling, nothing). I have had my antibodies tested numerous times, and I don't have Hashimoto's. My iron, B12, vitamin D, etc all seem to be optimal. Still taking all my supplements.

My full blood count was a bit odd the past two times (high RBC, high haemoglobin, high haematocrit, and low MCV), but apart from that, I don't know why I'm struggling so much. I don't know if it's my thyroid or maybe something else, like being on the mini pill for 8+ years without a break (suspected endo) or my mild sleep apnoea (not treated currently).

How can I tell if I need a dosage increase? Thank you so much, as always, for your help and support.

[TiggerMe Ambassador]

With TSH still at 3.99 this suggests you are still hypo and ready for an increase, aiming to get TSH around 1

[melissa-b in reply to TiggerMe]

Thank you so much, I'll message my GP and ask if I can increase my dose 🤞

[TiggerMe Ambassador in reply to melissa-b]

Sometimes it works better if you mention the word 'trial' increase and still being symptomatic as many GP's are just happy with you being within range🙃

[melissa-b in reply to TiggerMe]

thank you so much for the tip, I'll try that! That's exactly my experience with them - it's in range so I should feel great 😅

[FallingInReverse]

What are the exact results & ranges for b12, folate, d and iron?

Also, would be helpful to always get TSH, FT4 and FT3 together. Although with a TSH at 3.99 as Tiger says you’re probably due an increase, as you get closer to full replacement dose, your TSH won’t be enough to guide your dose changes.

[melissa-b in reply to FallingInReverse]

Thank you so much - I did ask for my T4 and T3 but they didn't do it this time (it was a different GP), super annoying! I also asked for B12 and folate, but they didn't do it. I've been on B12 injections since November 2023. Here are the results:

Serum vitamin D in November 2024: 155 nmol/L (no range)

Serum ferritin in November 2024: 107ug/L (310 ug/L: High ferritin)

Serum B12 November 2023: Serum vitamin B12 569 ng/L (no range)

Serum folate September 2023: Serum folate 19.8 ug/L (3.0 - 20.0)

[FallingInReverse in reply to melissa-b]

1) Levo low and slow increase - as other replies say.

If it was me, that seems the obvious step.

A couple other things to ponder later:

2) Magnesium can help with muscle twitches, and it’s a cofactor for hundreds of bodily processes.. Do you take magnesium?

3) Although your Bs are solid, some people feel better with B in upper range - closer to 8-900. B is water soluble so hard to take “too much” as long as you’re below 1000. , A b12 spray might be worth a try. Folate is perfect, around 20/top of range is what we aim for.

4) Get a full iron panel, including CRP, and cbc together the next time you get bloods.

If you iron, transferrin saturation % and ferritin (with normal CRP) are good, AND you have consistent (not fluctuating) high RBC, high hemoglobin, high hematocrit, low MCV) - Google “beta-thalassemia minor.” That would explain a consistent non-iron anemia low MCV.

Low MCV is an interesting marker - it suggests small red blood cells, small because they are new, as your body is being triggered to create more. This could be because of iron deficiency - which with your ferritin you most likely don’t have as long as your CRP was normal and iron and tsat are normal.

So none of your markers say anemia, but that may explain your low mcv so you can interpret your own bloods better going forward.

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Bottom line - Levo increase.

[melissa-b in reply to FallingInReverse]

Thank you so much for your reply! I do take magnesium citrate (works out to 222mg elemental magnesium, sometimes I take two), and I have Epsom salt baths every day or every other day. I think my B12 must be higher now as I've been having an injection every 8-12 weeks, which is why it wasn't tested for a year. I did have a full iron panel last year, and it was normal, which surprised me! I haven't had CRP tested for a while, though...

I've always had low MCV, but the other ones (high RBC, high hemoglobin, high hematocrit) have been high only since my last two blood tests (November and January) which is odd... It's also when my symptoms got worse, but I'm not sure what that means. Not super out of range, but a bit unusual! After Googling what you said, I wonder if I could be developing beta-thalassemia minor (if it's something you can develop?)

This was Nov:

RBC * 5.80 1012/L 3.80 - 5.30

Haemoglobin * 159 g/L 120 - 150

Haematocrit * 0.472 L/L 0.37 - 0.45

MCV * 81.3 fL 83 - 100

And Jan:

! Red blood cell (RBC) count 5.46 10*12/L 3.80 - 5.3010*12/L

! Haemoglobin estimation 152 g/L 120.00 - 150.00g/L

! Haematocrit 0.451 L/L 0.37 - 0.45L/L

! Mean corpuscular volume (MCV) 82.6 fL 83.00 - 100.00fL

[FallingInReverse in reply to melissa-b]

Although I too get cbcs often, when tracking iron related measures on a cbc you will only see the big picture every 6-12 months.

The lifespan of a red blood cell is 3-4 months, and mcv is a function of your new red blood cells so changes are seen no sooner than 3-6 months.

So track and actively manage your thyroid TSH and free Ts every 6-8 weeks when titrating , along with b12, folate, d3.

I get a full iron panel every time I get my thyroid numbers - iron, tibc, transferrin and/or transferrin saturation percent, and ferritin and crp-hs. If you’re not supplementing though this could be less frequent.

I too get a cbc 2-4 times a year but I don’t analyze for trends more frequently that every 6 months.

[SlowDragon Administrator]

Request next dose increase in Levo to 100mcg daily

Which brand of Levo are you currently taking

approx how much do you weigh in kilo

Even if we frequently start on only 50mcg, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until eventually on, or somewhere near full replacement dose (typically 1.6mcg levothyroxine per kilo of your weight per day)

cks.nice.org.uk/topics/hypo...

bnf.nice.org.uk/drugs/levot...

nhs.uk/medicines/levothyrox...

Adults usually start with a dose between 50 micrograms and 100 micrograms taken once a day. This may be increased gradually over a few weeks to between 100 micrograms and 200 micrograms taken once a day.

Some people need a bit less than guidelines, some a bit more

TSH should always be below 2 on levothyroxine

gponline.com/endocrinology-...

Graph showing median TSH in healthy population is 1-1.5

web.archive.org/web/2004060...

Comprehensive list of references for needing LOW TSH on levothyroxine

healthunlocked.com/thyroidu....

onlinelibrary.wiley.com/doi...

If symptoms of hypothyroidism persist despite normalisation of TSH, the dose of levothyroxine can be titrated further to place the TSH in the lower part of the reference range or even slightly below (i.e., TSH: 0.1–2.0 mU/L), but avoiding TSH < 0.1 mU/L. Use of alternate day dosing of different levothyroxine strengths may be needed to achieve this (e.g., 100 mcg for 4 days; 125 mcg for 3 days weekly).

sciencedirect.com/science/a...

The optimal daily dose in overt hypothyroidism is 1·5–1·8 μg per kg of bodyweight, rounded to the nearest 25 μg.

[melissa-b in reply to SlowDragon]

Hi SlowDragon, Thank you so much for your reply. I'm taking Mercury Pharmacy as I had an allergic reaction to another brand (I can't remember which one that was). I weigh 64kg, so I guess I should be closer to a 100mcg dosage! Thank you - hopefully the GP will let me increase it, sometimes they're just happy it's 'in range' (as you probably know).

I have had both TPO and TG antibodies tested a few times (with Thriva, Medichecks, and then just the Thyroid autoantibody level on the NHS), and the coeliac test was also negative <3

[SlowDragon Administrator in reply to melissa-b]

Always worth trying Gluten free diet 3-6 months

Have you had ultrasound scan of thyroid

If not request one via GP

Or private is £100

[melissa-b in reply to SlowDragon]

Thank you - I did, in November, completely clear scan!

[SlowDragon Administrator]

Have you tested BOTH TPO and TG antibodies

Significant minority of Hashimoto’s patients only have high TG antibodies (thyroglobulin)

NHS only tests TG antibodies if TPO are high

20% of autoimmune thyroid patients never have high thyroid antibodies and ultrasound scan of thyroid can get diagnosis

healthunlocked.com/thyroidu...

Paul Robson on atrophied thyroid - especially if no TPO antibodies

paulrobinsonthyroid.com/cou...

Gluten intolerance is often a hidden issue too.

Request coeliac blood test BEFORE considering trial on strictly gluten free diet

[SlowDragon Administrator]

6 Nov 2024:

Serum TSH level 5.04 mIU/L [0.38 - 5.33] Normal

Serum free T4 level 14.2 pmol/L [8.0 - 18.0] Normal

Serum free T3 level 5.3 pmol/L [3.8 - 6.0] Normal

You should have had dose increase in November after these results

After going up on my dosage in August, I initially felt anxious and headachy, but then started to feel a lot better

Suggest you initially increase by 12.5mcg …..by taking 75mcg and 100mcg on alternate days for 6 weeks, before increasing to 100mcg daily

Retest again 8 weeks later