Exosomes are nanosized extracellular vesicles (30–150 nm) with a bilayer lipid membrane that encapsulates proteins, lipids, and nucleic acids, first identified in the 1960s and expanded in application from disease diagnostics to targeted therapeutics. They are intercellular communicators with roles in physiological regulation and pathological progression, which have a large applications in gene therapy, drug delivery, tissue regeneration, and disease diagnostics. Their unique biological properties have attracted considerable attention for applications in regenerative medicine, targeted drug delivery, gene therapy, and disease diagnosis

This review highlights the dual biological nature of exosomes by discussing their beneficial 'Elixir' and detrimental 'Trojan Horse' functions. Exosomes activate signaling pathways such as Wnt/β-catenin and PI3K/Akt, deliver anti-aging molecules, and promote angiogenesis, owing to their properties such as biocompatibility, ability to cross the blood-brain barrier, and use as vectors for selective cargo delivery. Conversely, the same mechanisms that promote regeneration can also lead to undesired outcomes like tumor progression, drug resistance, immune responses suppression, and pathogenic factors spread underscore their “Trojan horse” potential. It means that the exosome's dual nature can presents challenges.

Exosomes represent a biological paradox, as mentioned. They can help with treatment as a healing elixir or, like a Trojan horse, lead to unintended consequences. A deeper understanding of the involved mechanisms is essential for developing safe and effective exosome-based therapies to understand this duality more deeply for harnessing their therapeutic potential while mitigating associated risks.