A single molecule activating two or three different receptors. Tirzepatide is a dual agonist; retatrutide is a triple agonist.

How narrowly a compound acts on its intended receptor rather than others. A more selective compound produces fewer effects outside the one being sought.

How long it takes for half of a compound to clear the body. It determines how often something has to be given, and it is one of the clearest differences between compounds sold under the same name.

What the body does to a compound: how it is absorbed, distributed, broken down and cleared.

What the compound does to the body. The other half of the pair.

Survives digestion well enough to work when swallowed. Almost no peptides do, which is why MK-677 being oral is a real distinction rather than a marketing one.

Produced by the body itself.

Introduced from outside the body.

The breakdown of stored fat. Compounds marketed for fat loss are usually described as increasing it.

The formation of stored fat. The opposite side of the same balance.