Which of the following hormones is not an amino acid derivative?

The correct answer is Option (2) → Insulin

By chemical nature, hormones fall into three classes: steroids, polypeptides and amino acid derivatives. Insulin is a polypeptide, a chain of many amino acids, not a small molecule made from a single amino acid.

Option (1) Thyroxine — An amino acid derivative. It is an iodinated derivative of tyrosine.

Option (2) Insulin — Not an amino acid derivative. It is a polypeptide hormone.

Option (3) Norepinephrine — An amino acid derivative. Like epinephrine, it is an amino acid derivative hormone.

Option (4) Epinephrine — An amino acid derivative. Like norepinephrine, it is an amino acid derivative hormone; the two mediate responses to external stimuli.

NCERT (2026-27 edition):
10.6 Hormones – “In terms of chemical nature, some of these are steroids, e.g., estrogens and androgens; some are poly peptides for example insulin and endorphins and some others are amino acid derivatives such as epinephrine and norepinephrine.”