Cabergoline
Also known as: Dostinex, Caber, Cabaser
Dopamine Agonist | Prolactin Management
Overview
Cabergoline is a potent, long-acting dopamine D2 receptor agonist that powerfully suppresses prolactin secretion from the anterior pituitary. It is FDA-approved under the brand name Dostinex for the treatment of hyperprolactinemic disorders, including prolactin-secreting pituitary adenomas (prolactinomas). In the bodybuilding and performance enhancement community, cabergoline is considered an essential ancillary compound when running 19-nor anabolic steroids such as nandrolone (Deca-Durabolin, NPP) and trenbolone, both of which can elevate prolactin levels through progestogenic activity. Elevated prolactin causes a range of undesirable effects including gynecomastia (particularly the progesterone-mediated variant), sexual dysfunction (erectile dysfunction, decreased libido, anorgasmia), mood disturbances, and lactation. Cabergoline's exceptionally long half-life of 63-69 hours allows for convenient twice-weekly dosing, and its high affinity for D2 receptors makes it significantly more potent and better tolerated than the older dopamine agonist bromocriptine.
Key benefits
- Potent suppression of prolactin levels, often normalizing them within days
- Prevents and reverses prolactin-related gynecomastia from 19-nor compounds
- Restores sexual function impaired by hyperprolactinemia (libido, erectile function, orgasm)
- Long half-life (63-69 hours) allows convenient twice-weekly dosing
- Significantly better tolerated than bromocriptine with fewer gastrointestinal side effects
- Effective at shrinking prolactin-secreting pituitary tumors
- Low doses required for bodybuilding prolactin management (0.25-0.5mg twice weekly)
Mechanism of action
Cabergoline exerts its effects by acting as a potent agonist at dopamine D2 receptors on lactotroph cells in the anterior pituitary gland. Prolactin secretion is tonically inhibited by hypothalamic dopamine acting on these D2 receptors, and cabergoline mimics this inhibitory signal with high affinity and prolonged duration. By activating D2 receptors, cabergoline suppresses prolactin gene transcription, reduces prolactin synthesis, and inhibits prolactin release into the bloodstream. In patients with prolactinomas, cabergoline also induces tumor shrinkage by inhibiting lactotroph cell proliferation and promoting apoptosis. The drug's selectivity for D2 receptors over D1 receptors contributes to its favorable side effect profile compared to less selective dopamine agonists. In the context of 19-nor steroid use, nandrolone and trenbolone stimulate prolactin release through their progestogenic activity, and cabergoline directly counteracts this elevation by restoring dopaminergic inhibition at the pituitary level.
Molecular data
- Type
- Ergoline-derived dopamine D2 receptor agonist
- Half-life
- ~63-69 hours
Indications
What the research community uses this compound for, with self-reported effectiveness.
19-Nor Compound Support
Medical Applications
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Delivery method
| Protocol | Dose | Frequency | Duration |
|---|---|---|---|
| — | 0.25mg | Twice weekly | — |
| — | 0.5mg | Twice weekly | — |
| — | 0.5mg | Once weekly (may split into two 0.25mg doses) | — |
| — | 0.5-1mg | Twice weekly | — |
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Nausea (especially during initial doses; mitigated by taking with food)
- Dizziness or lightheadedness
- Headache
- Nasal congestion or stuffiness
- Fatigue or drowsiness
- Orthostatic hypotension (feeling faint when standing up quickly)
Rare side effects
- Cardiac valve fibrosis or regurgitation (associated with long-term high-dose use, primarily in Parkinson's disease dosing -- far higher than bodybuilding doses)
- Impulse control disorders (compulsive gambling, hypersexuality, compulsive spending -- dose-dependent dopaminergic effect)
- Retroperitoneal fibrosis (extremely rare, associated with chronic high-dose use)
- Psychiatric effects (hallucinations, psychotic episodes -- very rare at standard doses)
- Pleural effusion or pulmonary fibrosis (rare, primarily with ergot-derived dopamine agonists at high doses)
Contraindications
- Known hypersensitivity to cabergoline or any ergot alkaloid
- History of cardiac valvular disease or clinically significant valvular regurgitation
- History of pulmonary, pericardial, or retroperitoneal fibrotic disorders
- Uncontrolled hypertension
- Concurrent use of dopamine antagonists (antipsychotics, antiemetics acting on D2 receptors)
- Severe hepatic impairment (cabergoline is extensively metabolized by the liver)
References
Primary literature and clinical-trial data informing this entry.