MK-2866 vs Raloxifene
Moderate Research vs FDA Approved
avoid Mechanism-based · 64% Both MK-2866 and Raloxifene carry hepatotoxic risk. Combining hepatotoxic compounds significantly increases liver damage potential. If unavoidable, include liver support (TUDCA/NAC) and monitor ALT/AST frequently.
Molecular Data
MK-2866 Raloxifene
Weight 389.33 Da 473.58 Da
Half-life ~24 hours ~28 hours
Type Non-steroidal selective androgen receptor modulator (C19H14F3N3O3) Benzothiophene-derived selective estrogen receptor modulator
Key Benefits
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
Raloxifene
01 Superior breast tissue estrogen receptor antagonism makes it the preferred SERM for gynecomastia reversal
02 No estrogen agonist activity in the uterus, avoiding the endometrial risks associated with tamoxifen
03 Estrogen agonist activity in bone preserves bone mineral density and reduces fracture risk
04 Lower overall thromboembolic risk compared to tamoxifen
05 Metabolized via glucuronidation rather than CYP2D6, avoiding the drug interaction concerns that affect tamoxifen
06 Simple once-daily oral dosing with a manageable 28-hour half-life
07 FDA-approved with decades of clinical safety data in postmenopausal women
Side Effects
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
Raloxifene
Hot flashes and increased sweating
Leg cramps and muscle spasms
Joint pain or stiffness
Peripheral edema (mild swelling in extremities)
Flu-like symptoms during initial weeks
Contraindications
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
History of deep vein thrombosis, pulmonary embolism, retinal vein thrombosis, or other venous thromboembolic events
Active or past history of stroke or transient ischemic attack
Known hypersensitivity to raloxifene hydrochloride or any excipients
Pregnancy or planned pregnancy (category X -- contraindicated)
Prolonged immobilization (e.g., post-surgical recovery, extended bed rest) due to elevated DVT risk
Severe hepatic impairment
Research Evidence
MK-2866 Raloxifene
Status Moderate Research FDA Approved
References 5 studies 4 studies
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.