An agonist or activator, is a drug or chemical that binds to and activates a protein, such as receptor or enzyme. Full agonists have high efficacy, eliciting a full response whilst occupying a small proportion of receptors. Partial agonists have a lower efficacy and cannot produce a maximal response, even if occupying a high proportion of receptors. Inverse agonists can bind to the same receptor binding-site as an agonist, but elicit an opposite effect. Researchers can save up to 50% on activators, agonists, partial agonists and inverse agonists from Hello Bio - they are up to half the price of other suppliers.