The paper describes a simple urine test that can spot growth‑hormone‑releasing peptides like GHRP‑2 by seeing if they knock a radioactive tag off the GHS‑R1a receptor. The test works in a dose‑dependent way and can detect GHRP‑2 for about 4.5 hours after it’s taken.

Growth hormone secretagogues (GHS) constitute a new GH deficiency treatment increasing exponentially in number and improved potency and bioavailability over the last decade. The growth hormone releasing activity makes these compounds attractive for the artificial improvement of the human sports skills, now that recombinant human growth hormone (rhGH) administration is effectively detected. The GHS family is extremely diverse both in number and chemical heterogeneity and keeps growing continuously. In this paper, a general screening test is proposed. To develop a universal method, the single common property of growth hormone secretagogues has been targeted: their capacity to bind to the GHS receptor 1a (GHS-R1a). Pretreated urine samples have been tested in a competition assay where eventually the GHS presence detached a radiolabelled ligand from the receptor in a dose-dependent manner. Blank urine samples were processed to determine potential age, gender and exercise effects, and to define a threshold beyond which a specimen is considered positive. Samples from a growth hormone releasing peptide 2 (GHRP-2) excretion study corroborated the screening assay applicability with a detection window of approximately 4.5 h, and results were confirmed by comparison with a dedicated LC-MS quantification of the intact compound.