This paper just out shows lack of effect of T3 on volunteers cardiac performance etc. Shows that the temporary "spike" in FT3 after dosing has no effect on heart parameters - ie can rule out this potential pproblem giving T3. Below see abstract and conclusions.
Front. Endocrinol., 28 February 2022 | doi.org/10.3389/fendo.2022....
Acute Effects of Liothyronine Administration on Cardiovascular System and Energy Metabolism in Healthy Volunteers
Shanshan Chen, George F. Wohlford, Alessandra Vecchie’, Salvatore Carbone Sahzene Yavuz, Benjamin Van Tassell, Antonio Abbate and Francesco S. Celi
Division of Endocrinology Diabetes and Metabolism, Virginia Commonwealth University, Richmond, VA, United States
Department of Biostatistics, Virginia Commonwealth University, Richmond, VA, United States
Department of Pharmacotherapy and Outcomes Sciences, Virginia Commonwealth University, Richmond, VA, United States
Division of Cardiology, Virginia Commonwealth University, Richmond, VA, United States
Department of Internal Medicine, ASST Sette Laghi, Varese, Italy
Department of Kinesiology and Health Sciences, College of Humanities and Sciences, Virginia Commonwealth University, Richmond, VA, United States
Context: The pharmacokinetics of liothyronine causes concerns for cardiovascular toxicity. While the effects of sustained increase in serum T3 concentrations are well described, little is known on the effects of acute changes in T3 concentrations due to rapid action of thyroid hormone.
Objective: To assess the clinical relevance of transient increase of T3 levels on cardiovascular system and energy metabolism.
Setting: Double-blind, three arms, placebo controlled, cross-over study
Study Participants: Twelve volunteers (3 females, 9 males), age 27.7 ± 5.1 years.
Intervention: Oral administration of liothyronine 0.7 mcg/kg, equimolar dose of levothyroxine (0.86 mcg/kg), or placebo in three identical study visits. Blood samples for total T3, free T4 were collected at times 0’, 60’ 120’ 180’ 240’. Continuous recording of heart rate, blood pressure, and hemodynamic data was performed using the volume clamp method. Resting energy expenditure was measured by indirect calorimetry. An echocardiogram was performed on each study visit at baseline and after the last blood sampling.
Main Outcome Measures: Changes in cardiovascular function and energy expenditure.
Results: Following the administration of liothyronine, serum T3 reached a Cmax of 421 ± 57 ng/dL with an estimated Tmax of 120 ± 26 minutes. No differences between study arms were observed in heart rate, blood pressure, hemodynamics parameters, energy expenditure, and in echocardiogram parameters.
Conclusions: The absence of measurable rapid effects on the cardiovascular system following a high dose of liothyronine supports the rationale to perform long-term studies to assess its safety and effectiveness in patients affected by hypothyroidism.
Update in sustained release T3 and new paper
New to t3 side effects,feeling better?ect.
