What should a patient taking Levothyroxine (levo) of 100 micrograms (mcg) be told about an elevated Thyroid-Stimulating Hormone (TSH) level and low Free Thyroxine (free T4) level?

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From the Guidelines

I recommend increasing your levothyroxine dose from 100 mcg to 125 mcg daily because your thyroid hormone levels are too low, as indicated by a TSH of 8.0 and free T4 of 0.71, which is not adequately replacing your thyroid hormone needs 1. You should be aware that the goal of adjusting your levothyroxine dosage is to bring your serum TSH into the reference range, and since your TSH is in the upper half of the reference range, increasing the dosage is a reasonable approach to alleviate symptoms suggestive of hypothyroidism, such as fatigue, weight gain, and cold intolerance 1.

From the Research

Patient Information

  • Your current TSH level is 8.0 and free T4 level is 0.71, which indicates that your levothyroxine dose of 100 mcg may need to be adjusted to achieve optimal thyroid hormone levels 2, 3.
  • You should discuss your test results with your physician, who will assess your overall health and adjust your levothyroxine dose as needed to maintain euthyroidism, which is the goal of hypothyroidism treatment 2, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Optimal free thyroxine levels for thyroid hormone replacement in hypothyroidism.

Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists, 2008

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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