"This is about facial domination," Cramer said on "Squawk on the Street." "They own the forehead [with] Botox; they own the eyelashes with Latisse; they own the jaw area with Juvederm, and now they own the double chin."
Allergan's deal is worth $2.1 billion, or $75 per share and will be in cash and stock. Kythera's shares closed Tuesday's session at $60.72.
"[The price makes sense] because this is the only company that will really be synergistic," Cramer said.
Kythera's shares surged by 22 percent Wednesday morning, while Allergan's stock rose about 1 percent.