Pym Particles—so named after their discoverer, Hank Pym—first existed in an elixir form that could be splashed on the object to alter its properties. Most notably, Pym Particles can affect an object's size, enlarging or shrinking it. However, it was later established by Scott Lang that they also affect the strength and durability of an object as well.
Eventually this elixir was made into a gas so if could be quickly aspirated for easier transportation. After accidentally transforming into Giant-Man, Pym further refined the chemical into a variety of color-coded pills. The particles still proved unstable as they trapped Pym at a height of 12 feet. Pym Particles work by the user either shunting mass to the "Kosmos Dimension" (for shrinking) or taking mass (for growing).
After repeated exposure to an unknown amount of Pym Particles, users can change size without having to take any more Pym Particles to trigger the change. Examples of this are Hank Pym, Janet van Dyne, and Cassie Lang. Simon Williams, who was given energy powers by Baron Zemo using Pym Particle-charged ions, was also permanently altered by these treatments along the strength and durability axes, but could not alter his size until directly treated with Pym Particles. Most uniforms for users of Pym Particles are treated with the particles so that they grow and shrink as the users do.
Users of Pym Particles
Users of Pym Particles include:
Side effects of Pym Particles
Some users of Pym Particles have had some side effects as a result of using them too much. The most notable is Hank Pym. Hank had several mental breakdowns, potentially from the strain of using Pym Particles, causing him to react differently from how he normally does. During one such breakdown he developed a new hyper-masculine heroic persona named Yellowjacket, who he felt would be more worthy of marriage to Van Dyne.
Another potential side effect is being stuck in an altered state. Pym was once unable to shrink down from his giant form for an extended duration otherwise the strain on his body would kill him.