# ACTH 1-39

> ACTH 1-39, the full-length, naturally occurring sequence of adrenocorticotropic hormone, is used therapeutically as a repository (depot) corticotropin injection for a range of conditions including infantile spasms (West syndrome), acute multiple sclerosis exacerbations, and certain other inflammatory or nephrotic conditions in some countries. It works upstream of corticosteroid drugs by stimulating the patient's own adrenal glands to produce cortisol, rather than supplying a synthetic corticosteroid directly. Diagnostic testing of adrenal function most often uses a shorter synthetic ACTH fragment (ACTH 1-24, cosyntropin), so ACTH 1-39 products are used predominantly for their therapeutic rather than diagnostic role. It is a prescription-only biologic requiring endocrinology or neurology supervision due to the risk of adrenal suppression and Cushingoid effects with repeated courses.

- URL: https://www.lifeconverted.com/peptides/acth-1-39
- Also known as: Corticotropin, Repository Corticotropin Injection, Acthar Gel
- Primary category: Other & Clinical
- Effectiveness rank: #25 in Other & Clinical
- Evidence level: Well studied
- Route: Intramuscular (Administered by intramuscular or deep subcutaneous injection as a repository (depot) gel formulation; diagnostic adrenal stimulation testing more commonly uses synthetic ACTH(1-24).)
- Dose range: 20-80 IU
- Dose tiers: low 20 IU; moderate 40 IU; high 80 IU
- Half-life: Plasma half-life of roughly 15 to 30 minutes, but the repository gel formulation prolongs absorption and biological effect over approximately 24 hours
- Timing: As directed by your clinician
- Cycle: Short, defined courses per indication, such as 2 to 3 weeks for an MS exacerbation or several weeks with tapering for infantile spasms on, Tapered off gradually rather than stopped abruptly; not used continuously long-term due to adrenal suppression risk off (Repeated or prolonged courses raise the risk of adrenal suppression and Cushingoid side effects and require close endocrinology or neurology monitoring.)
- Storage: Refrigerate the gel formulation at 2-8°C, protected from light; do not freeze.

## Mechanism of action

ACTH 1-39 binds melanocortin type 2 receptors on cells of the adrenal cortex, stimulating the synthesis and release of cortisol and, to a lesser extent, other adrenal steroids. In infantile spasms and MS relapses, the resulting rise in endogenous cortisol along with proposed direct melanocortin-receptor effects on the central nervous system is thought to underlie its therapeutic benefit, distinguishing it from direct corticosteroid administration alone. The repository (gel) formulation is designed for slow, sustained absorption from the injection site.

## Reported benefits

- Stimulates the body's own cortisol production for conditions responsive to increased glucocorticoid activity
- First-line option for infantile spasms in many treatment guidelines
- Used for acute exacerbations of multiple sclerosis as an alternative to high-dose corticosteroids
- Depot formulation allows less frequent dosing than short-acting corticosteroids

## Reported side effects

- Adrenal suppression and risk of adrenal insufficiency after stopping
- Cushingoid effects (weight gain, hypertension, fluid retention) with repeated or prolonged courses
- Increased infection risk due to immunosuppression
- Irritability and sleep disturbance, particularly in infants treated for spasms
- Hyperglycemia

## Common protocols

- Repository corticotropin injection course for infantile spasms (West syndrome)
- Short corticotropin course for acute multiple sclerosis exacerbations

## Stacking notes

Not typically combined with other corticosteroids concurrently, since it acts upstream to raise endogenous cortisol; hypothalamic-pituitary-adrenal axis suppression is monitored closely during and after treatment.

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