Mesotherapy for hair loss involves intradermal scalp injection of cocktails containing various combinations of vitamins, minerals, amino acids, peptides, and sometimes pharmaceuticals. The technique has been used in cosmetic dermatology since the 1950s, with hair loss applications gaining popularity since the 2000s. The specific composition of injections varies dramatically across clinics, making generalisations difficult and clinical comparisons challenging.

Common ingredients in commercial mesotherapy preparations include: biotin and B-complex vitamins (mechanism limited for non-deficient patients), copper peptides (potential mechanism through angiogenesis and growth factor release), procaine (anaesthetic and theorised circulation effects), various amino acids (cysteine, glutamine), hyaluronic acid (hydration and theoretical scaffold effect), and minoxidil (pharmacologically the most likely active ingredient). Some preparations include dutasteride for direct DHT suppression at the follicle.

The clinical evidence is generally weak for proprietary commercial preparations and stronger for specific single-ingredient injections (like dutasteride mesotherapy, which has dedicated trial evidence). Most multi-ingredient cosmetic mesotherapy products have minimal supporting evidence beyond patient satisfaction surveys. For patients considering mesotherapy, asking specifically what's in the injection and what evidence supports each ingredient helps separate cosmetic theatre from interventions with biological rationale. The most effective hair loss mesotherapy is typically simple, single-active-ingredient (dutasteride or minoxidil), rather than complex cocktails.