---
title: "Cosyntropin"
canonical_url: https://peptidelibrary.app/library/cosyntropin
description: "Synthetic peptide comprising the first 24 amino acids of corticotropin, approved as a diagnostic agent for screening adrenocortical insufficiency. It is a diagnostic tool rather than a therapy."
updated: 2026-11-07
publisher: Peptide Library
notice: "Research and educational use only. Not medical advice."
---

# Cosyntropin

Cosyntropin is a research peptide in the Melanocortin receptor agonist class. The N-terminal 24 residues of ACTH carry its full biological activity at the melanocortin-2 receptor of the adrenal cortex, while the omitted C-terminal residues account for most of the immunogenicity of the full hormone.

Synthetic peptide comprising the first 24 amino acids of corticotropin, approved as a diagnostic agent for screening adrenocortical insufficiency. It is a diagnostic tool rather than a therapy.

## Classification

- Type: FDA-approved ACTH(1-24) diagnostic
- Mechanism class: Melanocortin receptor agonist
- Development stage: Approved product
- Regulatory class: FDA-approved medicine

## Mechanism

The N-terminal 24 residues of ACTH carry its full biological activity at the melanocortin-2 receptor of the adrenal cortex, while the omitted C-terminal residues account for most of the immunogenicity of the full hormone. Receptor activation raises cyclic AMP and stimulates steroidogenesis, so the cortisol rise after a measured dose reports the adrenal cortex’s capacity to respond.

## Properties

- Molecular formula: C136H210N40O31S
- Molecular weight: 2,933.4 g/mol
- CAS number: 16960-16-0
- Studied routes: Intravenous, Intramuscular

## Evidence

- Evidence level: FDA Approved
- Highest documented: Regulatory review (FDA label)
- Human trials: 0
- Controlled human trials: 0
- Preclinical sources: 0

Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess.

### Studies

1. CORTROSYN (cosyntropin) for injection — FDA prescribing information (Amphastar), DailyMed. Regulatory label (FDA), human. Population: Adults being screened for adrenocortical insufficiency. Diagnostic cortisol response, interpreted with other tests [Source](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=746856e9-3930-4f6a-b8e6-a03845d6dd0b)
2. CORTROSYN (cosyntropin) for injection — FDA prescribing information (Amphastar), DailyMed. Regulatory label (FDA), human. Population: Children from birth to 17 years being screened for adrenocortical insufficiency. Diagnostic cortisol response, interpreted with other tests [Source](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=746856e9-3930-4f6a-b8e6-a03845d6dd0b)

## Safety

Human safety basis: FDA prescribing information

## Regulatory status

Cosyntropin is an FDA-approved product for specific labelled indications. Approval does not extend to the research contexts described on this page, and approved products are prescription medicines.

- FDA status: Approved
- Availability: Prescription-Only

## Frequently asked questions

### What is Cosyntropin?

Synthetic peptide comprising the first 24 amino acids of corticotropin, approved as a diagnostic agent for screening adrenocortical insufficiency. It is a diagnostic tool rather than a therapy.

### Is Cosyntropin FDA approved?

Yes. Cosyntropin is approved by the FDA, and approved products are prescription medicines. Approval is always for specific indications studied in clinical trials, so an approved status does not mean the compound is approved for every use it is discussed for. Research-chemical material sold under the same name is not the approved product.

### What peptides are similar to Cosyntropin?

Compounds most often compared with Cosyntropin include Bremelanotide, Melanotan II, Angiotensin II and Cetrorelix. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.

## References

- [Adrenal venous sampling: cosyntropin stimulation or not? — Eur J Endocrinol, 2019](https://pubmed.ncbi.nlm.nih.gov/31176302/)
- [Prevention of post-dural puncture headache in parturients: a systematic review and meta-analysis — Acta Anaesthesiol Scand, 2013](https://pubmed.ncbi.nlm.nih.gov/23278515/)
- [Cosyntropin-Stimulated Aldosterone Reserve of the Nondominant Adrenal Predicts Surgical Outcomes in Primary Aldosteronism — Hypertension, 2025](https://pubmed.ncbi.nlm.nih.gov/40755305/)
- [Intra-Lot and Inter-Lot Variability in Cosyntropin — Contact Context, 2021](https://pubmed.ncbi.nlm.nih.gov/35035309/)
- [Comparative effects of methylprednisolone and tetracosactide (ACTH(1-24)) on ischemia/reperfusion injury of the rabbit spinal cord — Arch Med Sci, 2018](https://pubmed.ncbi.nlm.nih.gov/30393502/)

Note: Dose figures are left out of this Markdown version. See the cited sources.