L-carnitine, a naturally occurring quaternary ammonium compound derived from amino acids lysine and methionine, has gained traction in topical skincare due to its ability to support skin health via targeted lipid metabolism. In cosmetic science, carnitine is particularly recognized for its role in facilitating the transport of long-chain fatty acids into mitochondria, enabling their subsequent β-oxidation. This biochemical function has proven useful in reducing sebum production on oily or acne-prone skin when applied topically. Studies have demonstrated that L-carnitine can significantly lower casual sebum levels in the skin without disrupting epidermal barrier integrity, making it ideal for inclusion in oil-control formulations like mattifying moisturizers and anti-acne gels.

In hair care, carnitine has shown promise as a bioenergetic booster that may improve follicular activity and reduce hair loss when used in conjunction with other actives. Some research suggests that L-carnitine L-tartrate can stimulate keratinocyte proliferation and mitigate oxidative stress in hair follicle cells, thereby supporting scalp vitality. While its standalone performance in hair care products requires further study, its synergistic value in anti-thinning treatments and energizing scalp serums makes it a compelling choice for brands targeting both male and female hair wellness markets.