In terms of supplementation, research has found that more than 3g of Carnitine supplements per day may induce side effects such as nausea, vomiting, abdominal cramps and or diahrrohea (National Institutes of Health, 2023)
Same chemical structure, same plasma half-life (~5 days), same mechanism
Carnitine and acylcarnitines are exchanged between different tissues as metabolic intermediates or signaling molecules, directly or indirectly affecting a variety of metabolic and biological pathways in almost all organs, and have broad impacts on interorgan communication and metabolic cooperation
Sci Total Environ 334:149159
Gut Health and the Thyroid Axis There is a strong connection between gut health and thyroid function, often referred to as the thyroid-gut axis