Tetracosactide
Cosyntropin · Synacthen · ACTH 1-24 · Tetracosactrin
Tetracosactide (Cosyntropin) is the pure, synthetic recreation of the first 24 amino acids of the human Adrenocorticotropic Hormone (ACTH) - the exact sequence holding 100% of the molecule's biological firepower. It is the absolute clinical standard for aggressive diagnostic interrogation of the adrenal glands, utilized instantly in emergency and endocrine settings to forcefully test the maximum acute cortisol-producing capacity of a failing adrenal cortex.
Use-case scores
0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.
- Sexual / hormonal3/10
Diagnostic ACTH analog. Not a tan peptide and not a gym cortisol hack.
Compound card
- Class
- ACTH(1-24) (cosyntropin / Synacthen diagnostic)
- Formula
- C136H210N40O31S
- Status
- Not FDA-approved · research use
How it works
Tetracosactide (also known as cosyntropin or Synacthen) is a synthetic peptide consisting of the first 24 amino acids of adrenocorticotropic hormone (ACTH). The full human ACTH has 39 amino acids, but biological activity resides entirely in the N-terminal 24 sequence.
Tetracosactide stimulates the adrenal cortex to rapidly produce cortisol and other corticosteroids. It is primarily used clinically as a rapid diagnostic test (the Synacthen Test) for adrenal insufficiency. Unlike long-term corticosteroid therapy, it relies on the body's own adrenal steroidogenic pathways.
Source: PMID: 6765449
Background & History
Tetracosactide (cosyntropin/Synacthen) is an essential diagnostic tool in endocrinology. The ACTH stimulation test has been the gold standard for diagnosing adrenal insufficiency for over 50 years. The short Synacthen test takes only 1 hour and can be performed in outpatient settings. Depot formulations (Synacthen Depot) have also been used therapeutically for infantile spasms and inflammatory conditions in various countries.
Research Use Cases
- ✓Adrenal insufficiency diagnosis
- ✓ACTH stimulation test
- ✓Infantile spasms (depot form)
- ✓Therapeutic use in inflammatory conditions
Dosing
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Diagnostic (Synacthen Test) | 250 mcg | Single IV or IM dose | FDA-approved diagnostic standard for adrenal insufficiency. |
| Therapeutic (Rare) | 1 mg Depot | Varies | Used rarely in cases like infantile spasms or MS exacerbations where endogenous cortisoid release is preferred over oral steroids. |
Administration
Timeline
Who it is for
Adrenal Function Testing
HighThe gold-standard diagnostic tool for Addison's disease and HPA axis evaluation.
Safety & Considerations
FDA-approved. Mostly used in supervised clinical settings for single-dose diagnosis. Therapeutic use carries risks similar to chronic corticosteroid exposure.
Regulatory & Legal Status
Not currently on the WADA 2026 Prohibited List. Policies may change - verify before competition.
Research Chemical
US Compounding: Not eligible / not available
⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.
Limits of current evidence
- Not a pigmentation protocol.
Verdict
Tetracosactide is cosyntropin. The 250 mcg stim test is endocrinology. It is not MT-2. Stimulating cortisol on purpose without a clinic is a bad idea.
Interactions & Contraindications
Exogenous corticosteroids will blunt the cortisol response and should be withheld before testing. Dexamethasone does not cross-react with cortisol assays.
Frequently Asked Questions
What is the Synacthen test?▼
References
- Dorin RI et al. “"The standard short Synacthen test in adrenal insufficiency".” Annals of Internal Medicine (2003). PMID: 12860585
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