Thyroid UK
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More T4, or should I get T3??


I've got Hashis and am on 75mcg Levothyroxine. Had to fight to get 75mcgs (they were happy to leave me at 50mcgs (and, in fact 25mcgs!) even though I was still symptomatic. I am starting to feel much better now but still not 100%.

I did a test with Medichecks to see where I am as my GP won't measure T3, and am wondering if I need more T4, or if adding T3 would be better? I think the GP's are unlikely to increase my T4 anymore as they were so reluctant to increase to 75mcgs, but I think I'm still under medicated. I'm happy to take matters into my own hands if the GP won't budge and order online, but considering if it's best to go T4 only, or T3 as well?

Results of this Friday's blood test are below:


Thyroid Function


FREE THYROXINE 17.52 pmol/L 12.00 - 22.00

TOTAL THYROXINE(T4) 90.7 nmol/L 59.00 - 154.00

FREE T3 3.89 pmol/L 3.10 - 6.80

Thyroid Antibodies


*399.500 IU/mL 0.00 - 115.00


*135 IU/mL 0.00 - 34.00



VITAMIN B12 312 pmol/L 140.00 - 724.00

FOLATE (SERUM) 6.17 ug/L 3.89 - 26.80


Inflammation Marker

CRP - HIGH SENSITIVITY 2.2 mg/L 0.00 - 5.00

Iron Status

FERRITIN 52.52 ug/L 13.00 - 150.00

Anyone have any sage advice? More T4 only, or a combo?



3 Replies


You are under medicated to have TSH 3.12 on 75mcgs. The goal of Levothyroxine is to restore the patient to euthyroid status. For most patients that will be when TSH is 1.0 or lower with FT4 in the upper range. FT4 needs to be in the upper range in order that sufficient T3 is converted. Read Treatment Options in Email if you would like a copy of the Pulse article to show your GP when you request a dose increase.

I would see how you feel on 100mcg which will raise FT4 and FT3 before considering adding T3.

Thyroid peroxidase antibodies are positive for autoimmune thyroid disease (Hashimoto's). There is no cure for Hashimoto's which causes 90% of hypothyroidism. Treatment is for the low thyroid levels it causes. Many people have found that 100% gluten-free diet is helpful in reducing Hashi flares, symptoms and eventually antibodies.

If you have symptoms of B12 deficiency outlined in the link below pop over to for advice about B12 312 and folate 6.17.

Ferritin is sub optimal, 75-100 is optimal. You can raise ferritin by supplementing iron which should be taken with 1,000mcg vitamin C to aid absorption and minimise constipation. Retest 4-6 months after you start supplementing and take iron 4 hours away from Levothyroxine.

CRP is low, which is good.

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b12 and ferritin still way too low and that is part of why you are not converting t4 levo into t3

email louise,

for a copy of the pulse article by Dr Toft

your TSH should be 1.0 or below

your free t4 and free t3 should be in balance and near top of their ranges

its clear your results are nothing like it and until ferritin,folate,b12,vit d3 are all halfway in their ranges the conversion of t4 into t3 cant happen

i suspect you may ultimately need to add t3 but try getting ferritin etc up first

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As you have Hashimotos you really need to try a strictly gluten free diet. Very many of us find it helps significantly - reducing symptoms and may lower antibodies slowly over time

Also selenium supplements can improve T4 to T3 conversion

See The Thyroid Pharmacist website for how important diet & lifestyle are

Also Amy Myers & Chris Kresser run good sites too

Hashimotos is connected to leaky gut, leading to poor nutrient levels, food sensitivities- usually gluten

Have you had vitamin D level checked? Very common to be low with any autoimmune disease, but especially Hashimotos.

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