Cabergoline

A prescription dopamine agonist for prolactinomas, which also circulates in AAS contexts on the theory of managing prolactin-pattern side effects (and for libido folklore).

Cabergoline is a dopamine agonist that acts on D2 receptors in the pituitary, where dopamine is the brake on prolactin release. Switching that brake on hard drops prolactin, which is its actual medical purpose: treating prolactin-secreting pituitary tumours. In the physique context it is used to blunt the prolactin rise from certain compounds, and recreationally for its effect on the refractory period. D2 activity outside the pituitary explains the impulse-control effects. The heart-valve problem is a different mechanism — most plausibly an off-target action at a serotonin receptor — and conflating the two makes valve risk look like a dose-dependent extension of the intended effect when it is not.

Excellent evidence for its actual indication — it is the standard prolactinoma drug. Evidence for steroid-cycle prolactin management: extrapolated, plausible, never trialed. The libido folklore traces to small studies in medical contexts, inflated in the retelling.

• Well evidenced and first-line for hyperprolactinaemia and prolactinoma, with high rates of prolactin normalisation and tumour shrinkage.
• Cardiac valve disease is the defining safety finding: studies in Parkinson's disease patients on high doses found substantially increased rates of valve regurgitation, which led to regulatory restrictions and, in some countries, withdrawal for that indication.
• At the much lower doses used for prolactin disorders the valve risk appears considerably smaller, and long-term studies are more reassuring, but echocardiographic monitoring is still standard practice in endocrinology.
• Impulse control disorders — pathological gambling, compulsive shopping, hypersexuality — are a recognised class effect of dopamine agonists and are frequently missed because patients do not connect the behaviour to the drug.
• There is no trial evidence for its non-medical use in the physique context.

Very long acting: effects and side effects persist well beyond the point at which someone stops thinking about the last dose, and prolactin suppression outlasts it substantially. That long tail is why unwanted effects can build gradually rather than appearing at once, and why this is a drug that needs a prescriber rather than a self-managed schedule.

Fibrotic heart-valve disease is established at the high cumulative exposures used in Parkinson's disease; risk at lower exposures appears smaller but remains actively monitored in medicine — and unmonitored entirely outside it. Impulse-control disorders are a documented dopamine-agonist class effect: gambling, compulsive behavior — real published case reports, exactly the failure mode a user won't self-detect. Nausea and orthostatic drops round it out.

• Anyone with existing heart valve disease
• Anyone with uncontrolled hypertension or a history of psychosis
• Anyone with a gambling, spending or compulsive-behaviour history
• Anyone using it without ever having measured prolactin
• Anyone pregnant, without specialist input

• Antipsychotics and metoclopramide, which are dopamine blockers and directly oppose it.
• Blood-pressure medication, compounding the orthostatic drop.
• Alcohol, which worsens the dizziness and hypotension.
• Macrolide antibiotics such as clarithromycin, which raise its levels.
• Other dopamine agonists, where impulse-control risk stacks.

• Echocardiogram — the specific monitoring this drug requires, and the one non-medical users almost never get.
• Fibrosis is not confined to heart valves: the label also warns about fibrosis of the pericardium, pleura, lungs and the retroperitoneal space, which can be progressive, and contraindicates use in anyone with a history of those disorders.
• Prolactin, which is the only way to know whether the dose is doing anything or is simply excessive.
• Blood pressure, particularly on standing, since it causes orthostatic hypotension.
• Impulse-control behaviour, and this is best asked of a partner or friend rather than yourself.
• Mood — depression and anxiety are reported and are easy to attribute to something else.

Because of the long half-life, effects taper over one to two weeks rather than stopping. Prolactin rebounds toward baseline, and in someone with an underlying prolactinoma it can return fully — which is why stopping medical treatment is a specialist decision. Impulse-control behaviours typically resolve after stopping, though the financial and relationship consequences do not. Anyone who has been on it long-term should raise stopping with a clinician rather than simply ceasing.

US: prescription-only. Products outside licensed dispensing are unapproved and of unverifiable authenticity.

Papers about this compound, not proof of the claims above. A title says what was studied, which is sometimes a negative result or a different question entirely.

• Safety of Cabergoline for Prolactinoma in Pregnancy: A Systematic Review and Meta-Analysis
  Clin Endocrinol (Oxf), 2025
• Cabergoline Use and Pregnancy Outcomes: A Systematic Review
  Birth Defects Res, 2025
• The effectiveness and safety of aripiprazole, bromocriptine, and cabergoline in the treatment of hyperprolactinemia: a systematic review and network meta-analysis
  Expert Opin Drug Saf, 2025

• Cabergoline2006
• Cabergoline in acromegalyPituitary · 2017
• Cabergoline: a review of its use in the inhibition of lactation for women living with HIVJ Int AIDS Soc · 2019
• Pituitary acting drugs: cabergoline and pasireotidePituitary · 2022
• Approach to the Patient With ProlactinomaJ Clin Endocrinol Metab · 2023
• Cabergoline-induced manic episode: case reportTher Adv Psychopharmacol · 2016
• Cabergoline Use and Pregnancy Outcomes: A Systematic ReviewBirth Defects Res · 2025
• Real-world value of cabergoline in the treatment of acromegalyBest Pract Res Clin Endocrinol Metab · 2024
• Is Cabergoline Safe and Effective for Postpartum Lactation Inhibition? A Systematic ReviewInt J Womens Health · 2020
• Safety of Cabergoline for Prolactinoma in Pregnancy: A Systematic Review and Meta-AnalysisClin Endocrinol (Oxf) · 2025
• Safety of Cabergoline for Postpartum Lactation Inhibition or Suppression: A Systematic ReviewJ Obstet Gynaecol Can · 2020
• Cabergoline for preventing ovarian hyperstimulation syndromeCochrane Database Syst Rev · 2012