OnePin Peptide Library · Hormonal
Cabergoline (Dostinex / Caber)
Dostinex
Cabergoline is a long-acting ergot-derived dopamine D2 receptor agonist. It is FDA-approved under the brand name Dostinex (and internationally as Cabaser) for the treatment of hyperprolactinemia, whether idiopathic or secondary to a pituitary prolactin-secreting adenoma (prolactinoma). In Europe and some other markets it is also approved as an adjunct in Parkinson's disease at higher doses. It is strongly preferred over the older dopamine agonist bromocriptine because of its longer half-life, twice-weekly dosing schedule, and better tolerability profile.
Take 0.25-0.5 mg twice weekly (for example Monday and Thursday) with food - empty-stomach dosing amplifies nausea. Bedtime dosing sidesteps peak nausea and dizziness by sleeping through the Tmax. Start at 0.25 mg twice weekly and only increase if prolactin remains elevated. Monitor for orthostatic hypotension, especially on first doses.
Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.
How it works
Cabergoline is a potent and selective agonist at dopamine D2 receptors, with much weaker activity at D1, serotonergic (5-HT2A, 5-HT2B), and adrenergic receptors. In the anterior pituitary, D2 stimulation on lactotroph cells directly suppresses prolactin synthesis and secretion - this is the basis of its approved use in hyperprolactinemia and its off-label use in controlling prolactin elevation from 19-nor anabolic steroids.
Cabergoline is a potent and selective agonist at dopamine D2 receptors, with much weaker activity at D1, serotonergic (5-HT2A, 5-HT2B), and adrenergic receptors. In the anterior pituitary, D2 stimulation on lactotroph cells directly suppresses prolactin synthesis and secretion - this is the basis of its approved use in hyperprolactinemia and its off-label use in controlling prolactin elevation from 19-nor anabolic steroids.
The long half-life (~63-68 hours) reflects tight binding to pituitary D2 receptors and is responsible for the clinically useful 2x/week dosing schedule. A single 0.5 mg dose suppresses prolactin for over a week in most users.
At the much higher doses used in Parkinson's disease (3+ mg/day), serotonin 5-HT2B receptor agonism on cardiac valve leaflets has been implicated in the valvulopathy cases reported with chronic high-dose use. At the sub-1 mg weekly doses used for hyperprolactinemia, cardiac valve risk has been studied extensively and appears minimal but not zero - periodic echocardiographic monitoring is reasonable with long-term use.
What to expect
Day 1-3: mild nausea, dizziness, possible orthostatic hypotension on the first dose. Most users acclimate within 3-5 doses.
Week 2-4: measurable prolactin reduction. Symptomatic improvement in libido, erectile function, galactorrhea, and mood begins.
Month 1-3: full symptomatic benefit. Dose can be titrated down to the minimum effective maintenance level. For 19-nor steroid users, cabergoline is continued throughout the cycle and tapered off post-cycle.
Evidence
Interactions & stacking
What's safe to combine, and what belongs in a separate pin.
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Side effects & safety
Commonly reported
- Nausea (especially first doses) - mitigated by food and bedtime dosing
- Dizziness, orthostatic hypotension
- Headache
- Fatigue
- Vivid dreams or disrupted sleep
- Nasal congestion
Less common & notes
- Constipation, dry mouth, depression or mood changes, impulse-control disorders (pathological gambling, hypersexuality, compulsive shopping - class effect of dopamine agonists), hallucinations (rare, more common at higher Parkinson's doses).
- Chronic high-dose use (Parkinson's-range 3+ mg/day) has been associated with cardiac valve fibrosis via 5-HT2B agonism - risk is dose-dependent and minimal at hyperprolactinemia doses.
- Raynaud's-like peripheral vasospasm is a rare ergot-class side effect.
- Raises risk of pleural / retroperitoneal fibrosis with chronic high-dose use.
Pharmacokinetics
Storage. Store at controlled room temperature (20-25°C / 68-77°F). Protect from light. Keep in original container. Shelf life typically 2-3 years from manufacture date. Keep out of reach of children - single tablet overdose can be significant in a child.
Regulatory status
Prescription-only (Rx) dopamine agonist. FDA-approved under brand name Dostinex (Pfizer / Pharmacia) in the United States for hyperprolactinemia. Also available internationally as Cabaser (higher-dose formulation for Parkinson's) and under various generic names. Prescription-only in the United States. Not a controlled substance. Not prohibited by WADA - dopamine agonists are not on the current WADA prohibited list.
Put it to work
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The guide & community
The complete Cabergoline (Dostinex / Caber) walkthrough, real protocol discussion and coaching live inside the BlessUp community on Skool.
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