Cabergoline vs MK-2866
FDA Approved vs Moderate Research
synergistic Mechanism-based · 55% MK-2866 supports hormonal recovery from suppression caused by Cabergoline. Standard protocol — begin PCT after the suppressive compound has cleared based on its half-life.
Molecular Data
Cabergoline MK-2866
Weight 451.60 Da 389.33 Da
Half-life ~63-69 hours ~24 hours
Type Ergoline-derived dopamine D2 receptor agonist Non-steroidal selective androgen receptor modulator (C19H14F3N3O3)
Key Benefits
Cabergoline
01 Potent suppression of prolactin levels, often normalizing them within days
02 Prevents and reverses prolactin-related gynecomastia from 19-nor compounds
03 Restores sexual function impaired by hyperprolactinemia (libido, erectile function, orgasm)
04 Long half-life (63-69 hours) allows convenient twice-weekly dosing
05 Significantly better tolerated than bromocriptine with fewer gastrointestinal side effects
06 Effective at shrinking prolactin-secreting pituitary tumors
07 Low doses required for bodybuilding prolactin management (0.25-0.5mg twice weekly)
MK-2866
01 Increases lean body mass in a dose-dependent manner with clinical trial support
02 Preserves muscle mass during caloric deficit or catabolic conditions
03 Selective tissue activity reduces androgenic side effects compared to anabolic steroids
04 Oral bioavailability eliminates the need for injections
05 Does not aromatize to estrogen, avoiding gynecomastia and water retention
06 Improves physical function and stair-climbing power in clinical populations
07 Long 24-hour half-life allows convenient once-daily dosing
08 Mild side effect profile at commonly studied doses
Side Effects
Cabergoline
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)
MK-2866
Mild testosterone suppression (dose-dependent, typically 10-30% reduction at 25 mg)
HDL cholesterol reduction (10-20% suppression observed in clinical trials)
Headaches, particularly during the first 1-2 weeks
Mild back pain or muscle cramps
Transient fatigue toward the end of longer cycles
Slight reduction in libido at higher doses or extended cycle lengths
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)
Active liver disease or significantly elevated liver enzymes
Hormone-sensitive cancers (breast, prostate) without oncologist clearance
Pregnancy or breastfeeding (potential endocrine disruption to fetus/infant)
Individuals under 21 years of age (risk of premature HPTA disruption during development)
Concurrent use of hepatotoxic medications without liver function monitoring
Known hypersensitivity to MK-2866 or any formulation excipients
Competitive athletes subject to WADA or USADA anti-doping testing
Research Evidence
Cabergoline MK-2866
Status FDA Approved Moderate Research
References 5 studies 5 studies
FDA Approved Yes No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.