Why animal insulin was replaced by the recombinant human insulin?

The correct answer is Option (2) → It causes allergy.

Insulin was first taken from the pancreas of slaughtered cattle and pigs. Recombinant human insulin is made by putting the human insulin genes into bacteria, which then make the hormone.

(1) It was less expensive to produce. — Incorrect. This is not the reason. The trouble with animal insulin was the reaction it caused in some patients.

(2) It causes allergy. — Correct. Animal insulin is a foreign protein, so some patients developed allergy or other reactions to it. Human insulin made by bacteria does not have this problem.

(3) It was less effective. — Incorrect. It did lower blood sugar. The problem was the reaction to the foreign protein.

(4) The isolation process was easier to perform. — Incorrect. Isolating insulin from animal pancreas was the old method. Growing bacteria that make human insulin is the simpler way.

NCERT Extract:
Genetically Engineered Insulin – …