L-carnitine and oily skin: what are the effects?

The oily skin is characterized by excessive sebum production by the sebaceous glands, i.e., hyperseborrhea. This sebum, primarily composed of triglycerides, wax esters, squalene, and free fatty acids, normally plays a protective role as part of the hydrolipid film that maintains the hydration and suppleness of the epidermis. However, when produced in excess, it can lead to a shiny appearance, uneven skin texture, and an increased risk of pore obstruction. Hyperseborrhea can result from hormonal factors, notably an increased sensitivity of the sebaceous glands to androgens, as well as from genetic predispositions, disturbances in the skin microbiota, or environmental factors.

To care for oily skin, one should aim to mitigate excess sebum without impairing the skin barrier.

In this context, the L-carnitine appears promising for oily skin due to its role in cellular energy metabolism. This molecule functions as a long-chain fatty acid transporter, directing these fatty acids to the mitochondria for oxidation and energy production. In sebaceous glands, a large portion of sebum synthesis depends on the availability of these fatty acids. By promoting their mitochondrial use, L-carnitine may help reduce the intracellular lipid pool and thereby decrease sebum production. This mechanism notably involves the activation of carnitine acyltransferase, an enzyme that mediates mitochondrial fatty acid transport.

A study assessed the efficacy of L-carnitine in regulating sebum production through an in vitro. The researchers used a human sebocyte cell line (SZ95) to examine the molecule’s impact on lipid metabolism. When exposed to 0.5% and 1% L-carnitine, these cells showed a significant increase in β-oxidation, i.e., the process of fatty acid breakdown within the mitochondria. In parallel, intracellular lipid levels decreased in a dose-dependent manner, indicating a reduced pool available for sebum synthesis.