The stratum corneum is designed to keep things out. Its tightly packed corneocytes and lipid matrix create a barrier that blocks molecules larger than approximately 500 daltons from penetrating. Many of the most effective active ingredients — peptides, coenzymes, growth factors — are well over this limit. Liposomal encapsulation solves this problem by creating a delivery vehicle that passes through the barrier intact.
A liposome is a spherical vesicle composed of one or more phospholipid bilayers — the same material that makes up cell membranes. The active ingredient is trapped inside the liposome's aqueous core or embedded in its lipid shell. When applied to skin, the phospholipid bilayers fuse with the lipid matrix of the stratum corneum, releasing the payload directly into the viable epidermis.
The advantage is not just penetration — it is targeted delivery. Liposomes can be engineered for specific release profiles: immediate release for surface-acting ingredients, sustained release over 8-12 hours for repair ingredients, or pH-triggered release that activates only when the liposome reaches the lower epidermis where pH is different.
Without encapsulation, many ingredients degrade on the skin surface before they can act. NMN, for example, is highly water-soluble and does not cross the lipid barrier. Copper peptides oxidise rapidly. Coenzyme Q10 is too large to be absorbed. Liposomal protection keeps these ingredients stable until they reach their target tissue.
The quality of liposomal formulation varies dramatically. Single-layer (unilamellar) vesicles provide more consistent release than multi-layer (multilamellar) ones. Particle size matters: vesicles under 100 nm is absorbed more reliably than larger ones. And the phospholipid composition — whether derived from soy, sunflower, or synthetic sources — affects both stability and fusion efficiency with skin lipids.