Trials4us are part of Richmond Pharmacology Ltd. Richmond Pharmacology are the UK's largest Phase I & II Clinical Research Organisation (CRO), and the only one based over 2 hospital sites: St George's Hospital and the Mayday Hospital in the London area.

Every prescription and over-the-counter medicine has to go through 4 phases of controlled testing:

Phase I

The earliest trials carried out on a small group of healthy volunteers to establish a dosage range for the medicine and see how healthy bodies absorb the new treatment.

Phase II

Testing occurs on patients who have the condition for which the new medicine is being developed.

Phase III

Tests how well the medicine works and its safety on a much larger group of patients.

Phase IV

After the medicine is granted a licence this phase reviews how effective the medicine has been in its wider use.

Trials4us works with Phase I volunteers.