Effects of Supraphysiological Doses of Levothyroxine on Sleep in Healthy Subjects: A Prospective Polysomnography Study

Table 1

Serum concentrations of thyroid hormones at baseline and during maximal dosage of levothyroxine (L-T4) ¹.

Thyroid hormone (normal range)	Baseline		During T4 treatment		Δ^2		𝑃
	Median	Quartile range	Median	Quartile range	Median	Quartile range
T3 (0.8–1.6 μg/L)	1.3	1.2–1.4	2.3	2.0–2.9	1.2	0.8–1.4	.0005
T4 (45–125 μg/L)	89	76–91	197	169–224	108	88–136	.0002
FT3 (2.3–5.1 ng/L)	4.2	3.7–4.7	6.9	5.2–7.2	2.3	1.2–3.1	.0015
FT4 (7–19 ng/L)	10.8	9.2–12.2	45.8	32.6–53.6	37.5	21.7–41.5	.0002

1For abbreviations see text.
²Δ refers to intraindividual differences.