Allergan is buying a biotech company for $2.1 billion

Allergan is buying Kythera Biopharmaceuticals for $2.1 billion.

In a statement on Wednesday, the companies announced that Allergan will pay $75 per Kythera share; 80% will be in cash, and the remaining 20% in new Allergen shares for Kythera shareholders.

Allergan is a pharmaceutical company and the maker of botox.

By acquiring Kythera, Allergan adds an injection that treats double chin to its portfolio, called Kybella, the companies noted.

Brent Saunders, CEO of Allergan, said in the statement: "KYBELLA™ is an exciting new product that offers patients the first and only clinically-proven, non-surgical treatment for submental fullness (excess fat under the chin). As a leader in aesthetics, we know our customers are looking to offer their patients new options beyond traditional facial aesthetics."

Kybella has been approved by the FDA, with the green light pending in Swtizerland, Australia, and Canada, according to the statement.

The deal is subject to the approval of Kythera shareholders.