What are liposomes?

When you take a traditional supplement by mouth, its contents are broken down at several stages in the digestive system, which often means low bioavailability and a low absorption rate. Liposomal technology helps protect the nutrient as it passes through digestion, so that more of it is absorbed and reaches the cells and tissues where it's needed.

Liposomes are highly efficient carrier systems: first developed in medicine, they're now widely used to make nutrients — and cosmetic ingredients — more bioavailable within the body. You may have heard of liposomal supplements, but do you know what makes them so effective?

The word 'liposome' comes from two Greek words: 'lipos' (fat) and 'soma' (body). Liposomes were first described in 1964 by Alec Bangham and his colleague R.W. Horne, who were examining a dispersion of phospholipids in water under an electron microscope. Today they're used to encapsulate and carry nutrients, medicines and cosmetic agents to the cells and tissues for improved uptake and absorption.

A liposome is a very small spherical vesicle made of phospholipids — a type of lipid that is a major structural component of our cell membranes (the outer layer of the cells).

More about phospholipids

One of the most important jobs of phospholipids is to regulate the transport of nutrients and other substances across the cell membrane. In this role they act as 'gatekeepers', helping determine what goes in and out of the cell. Other functions of phospholipids include:

• Allowing cell membranes to stay fluid, which helps cells change shape and adapt to their environment
• Working as signalling molecules in cellular communication (for example, signalling white blood cells to travel to a site of infection or injury)
• Helping protect cell membranes against oxidative damage caused by free radicals

How do liposomes work?

To understand how liposomes work, it helps to start with the structure of a phospholipid:

• A phospholipid molecule has two fatty-acid chains (the 'tail') and a phosphate group (the 'head'), joined by a glycerol molecule.
• The fatty-acid tails are 'hydrophobic' (repelled by water).
• The phosphate head is 'hydrophilic' (attracted to water).

In an aqueous solution, phospholipid molecules self-assemble so that the water-repelling tails turn inward, away from the water, while the water-loving heads turn outward toward it. This arrangement forms a closed, spherical structure — a liposome — with a hollow watery core surrounded by a double-layer (bilayer) membrane. In liposomal supplements, the active nutrients are loaded into these microscopic vesicles to be carried and delivered to the cells. What's neat is that they can hold both water-soluble substances (in the central watery space) and fat-soluble nutrients (within the membrane).

Benefits of liposomal encapsulation

Liposomes form a protective barrier around their contents. This helps shield the enclosed nutrients from enzymes in the mouth and stomach, from digestive juices and bile acids, and from free radicals, so that more of the nutrient survives the journey through digestion. [1] Because liposomes are made of the same kind of fat as our own cell membranes, they can also blend with and cross those membranes readily to reach the target cell.

In short, liposomal supplements can offer:

• Improved bioavailability of nutrients
• Better uptake and absorption of nutrients by cells and tissues
• Gentler digestion than the stomach upset a high oral dose can sometimes cause

Liposomal encapsulation is a well-established delivery method, supported by decades of research. Reviews note that liposomes can improve an ingredient's solubility, bioavailability and stability, [2] and pharmacokinetic studies comparing liposomal and conventional multivitamin/mineral formulations have observed differences in how the nutrients are absorbed. [3]

References:

1. Nsairat H, Khater D, Sayed U, Odeh F, Al Bawab A, Alshaer W. Liposomes: structure, composition, types, and clinical applications. Heliyon. 2022;8:e09394.
2. Liu F, et al. A Review of Liposomes as a Drug Delivery System: Current Status of Approved Products, Regulatory Environments, and Future Perspectives. Molecules. 2022;27(4):1372.
3. Ko J, et al. Pharmacokinetic Analyses of Liposomal and Non-Liposomal Multivitamin/Mineral Formulations. Nutrients. 2023;15(13):3073.