Fifty years of MPS — the quietest workhorse in topical medicine

Some drugs arrive with fanfare and fade. Others are introduced quietly and simply refuse to stop being useful. Mucopolysaccharide polysulfate (MPS) belongs firmly to the second group. A semi-synthetic glycosaminoglycan built on a heavily sulphated chondroitin backbone, it has been in continuous clinical use since the 1960s — and it remains the pharmacological backbone of heparinoid topicals today.

How it holds water

The defining feature of MPS is its density of sulphate groups, which give it an enormous capacity to form hydrogen bonds with water. Applied to skin, MPS draws and holds water in the outer dermis, restoring the viscoelasticity that dry, photo-aged skin loses. Just as importantly, it appears to stimulate the skin’s own synthesis of hyaluronate — so the tissue is coaxed into making more of its own natural moisturiser.

Reaching the dermis despite its size

A reasonable objection is that MPS is a large molecule — well over 500 daltons — and large molecules are not supposed to cross the stratum corneum. Yet laser-Doppler studies keep showing that topically applied MPS increases local skin blood volume and basal sweating, functional changes that can only originate below the epidermis. Whatever the precise route, the pharmacodynamic evidence indicates the molecule reaches tissue that matters.

A heparinoid with three jobs

Clinically, MPS does three things at once: it hydrates, it calms inflammation, and — as a heparinoid — it improves microcirculation and has a mild antithrombotic action on superficial vessels. That combination explains its longevity across such a broad set of indications, from a footballer’s contusion to the chronically dry shins of an older patient. It is not glamorous, and it never trended. It has simply worked, for fifty years — which in therapeutics is the highest compliment a molecule can earn.