The Claim
Long-term suppressive levothyroxine therapy at doses of 150–184 mcg/day for 3–5 years has no significant effect on sex-hormone-binding globulin levels in premenopausal and postmenopausal women compared to matched controls.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Taking levothyroxine at doses of 150–184 mcg per day for 3 to 5 years does not change sex-hormone-binding globulin levels in women, regardless of whether they are premenopausal or postmenopausal.
See the scientific wording
Long-term suppressive levothyroxine therapy (150–184 mcg/day for 3–5 years) does not significantly alter sex-hormone-binding globulin (SHBG) levels in either premenopausal or postmenopausal women, as compared to age-, weight-, and menopausal status-matched controls, indicating no measurable effect on hepatic hormone metabolism in this population.
Even when the thyroid hormone level stays high for years, the liver keeps making the same amount of the protein that binds sex hormones, so the levels of that protein in the blood do not change.
What the research says
1 studyThis study found that women taking high doses of thyroid hormone for several years had the same levels of a liver protein (SHBG) that binds sex hormones as women not taking the drug — whether they were before or after menopause. So, the thyroid medicine doesn’t seem to change this particular liver function.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.