Does cold weather affect hypo?

[Arpeggio]

The weather is colder and my FT4 has fallen below the reference range.

Is hypothyroid adversely affected by cold weather? I'd be interested to find out from others if this is a thing.

[SlowDragon Administrator]

What thyroid hormone replacement are you on?

If just Levothyroxine then FT4 below range means you're under medicated

If taking NDT then low Ft4 is common. Most important results is FT3

[Arpeggio in reply to SlowDragon]

I'm on levothyroxine 75mcg and 20mcg of liothyronine. My previous labs have been in reference range but not optimal, been on T3 meds so just done new labs that's how I found out my FT4 has dropped below reference range and wondering why. Could it be I'm affected by cold winter weather? I'm just waiting for the FT3 result.

[SlowDragon Administrator in reply to Arpeggio]

Some of us on Levothyroxine plus T3 need good levels of FT4 and FT3

Others don't seem to mind low Ft4

Important to regularly test vitamin levels too

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

If/when also on T3, make sure to take last dose 8-12 hours prior to test, even if this means adjusting time or splitting of dose day before test

Is this how you do your tests?

[Arpeggio in reply to SlowDragon]

Yes, that is how I do tests.

[SlowDragon Administrator]

Previous post shows absolutely dire iron and low ferritin

healthunlocked.com/thyroidu...

What has been done about that

Vitamin D was still too low

[Arpeggio in reply to SlowDragon]

Vitamin D is now in range, I made a point of sunbathing in a bikini most days without sunscreen over the summer. Ferritin is in range but iron is still low.

[SlowDragon Administrator in reply to Arpeggio]

So you will need to work on improving low iron levels

Eating liver or liver pate once a week, plus other iron rich foods like black pudding, prawns, spinach, pumpkin seeds and dark chocolate, plus daily orange juice or other vitamin C rich drink can help improve iron absorption

Links about iron and ferritin

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

drhedberg.com/ferritin-hypo...

restartmed.com/hypothyroidi...

Post about iron supplements

healthunlocked.com/thyroidu...

[humanbean]

It takes energy to keep warm. Being hypothyroid reduces the ability of the body to stay warm. In winter in particular, more energy is diverted from other functions in the body to try and stay warm. Many of us have found that TSH increases and Free T4 and Free T3 reduce in winter, and we need higher doses of thyroid hormones.