Single Center, Open-Label, Randomized Crossover Trial on Drug-Drug Interactions of Levothyroxine/Magnesium-Citrate and Levothyroxine/Magnesium-Aspartate in Healthy Subjects-The ThyroMag Trial.

What Was Tested

This randomized controlled trial looks at Vitamin D, K2, Magnesium and Zinc.

Divalent cations such as calcium and ferrous sulfate interfere with the absorption of levothyroxine due to complexing.

Participants received all three treatments, separated by a washout period, but were randomly allocated 1:1:1 to one of three treatment sequences.

Who Took Part

The age groups tagged for this paper are young adults, adults and middle-aged adults, both men and women.

How the Study Was Run

The design is described as randomized, open-label and crossover.

The participants were allocated by chance, so the Vitamin D, K2, Magnesium and Zinc group and the comparison group should start out alike.

Everyone knew when Vitamin D, K2, Magnesium and Zinc was being given (open label), which is simpler to run but leaves more room for expectations to affect what is reported.

Each person switched between Vitamin D, K2, Magnesium and Zinc and the comparison at some point, usually with a gap in between.

What Was Measured

The researchers measured thyroxine (T4) over a 6-h period after ingestion.

The primary endpoint was the area under the curve (AUC) of thyroxine; secondary endpoints were Cmax and Tmax.

Topics PubMed links to this paper include Thyroxine, Healthy Volunteers, Drug Interactions, Magnesium Compounds, Citric Acid, Aspartic Acid and Area Under Curve.

Author keywords: clinical trial, drug–drug interaction and levothyroxine absorption.

What This Means in Plain Language

The paper is a randomized, open-label and crossover study of Vitamin D, K2, Magnesium and Zinc.

The publication is from 2025 (Clinical and translational science), a journal based in United States.

More context: the Vitamin D, K2, Magnesium and Zinc compound page, all human trials.