RAD-140 vs YK-11
Emerging vs Limited Research
monitor Researched · 90% YK-11 and RAD-140 are sometimes stacked by users seeking to combine YK-11's myostatin inhibition with RAD-140's potent AR agonism. This combination compounds the risk of testosterone suppression and liver enzyme elevation, as both compounds are hepatically metabolized. If combining, comprehensive blood work (liver function, hormones, lipids) is essential at baseline, mid-cycle, and post-cycle. Liver support supplementation is strongly recommended.
Molecular Data
RAD-140 YK-11
Weight 393.83 Da 430.54 Da
Half-life ~60 hours ~6-10 hours
Type Nonsteroidal selective androgen receptor modulator (C20H16ClN5O2) Steroidal selective androgen receptor modulator with myostatin-inhibiting properties (C25H34O6)
Key Benefits
RAD-140
01 Potent anabolic activity in muscle tissue with high oral bioavailability
02 Tissue-selective action sparing the prostate and other androgen-sensitive organs
03 No aromatization to estrogen (no estrogen-related side effects such as water retention or gynecomastia)
04 No conversion to DHT (reduced risk of hair loss and prostate stimulation compared to testosterone)
05 Long half-life (~60 hours) permitting convenient once-daily oral dosing
06 Neuroprotective properties observed in preclinical models
07 Increased lean body mass and reduced fat mass in preclinical studies
YK-11
01 Dual mechanism combining partial AR agonism with myostatin inhibition via follistatin upregulation
02 May theoretically promote muscle growth beyond what AR activation alone can achieve by removing myostatin-mediated growth limits
03 Steroidal structure providing oral bioavailability without requiring injection
04 Partial AR agonist activity may confer tissue selectivity with reduced androgenic side effects compared to full agonists (theoretical, not demonstrated in vivo)
05 Short half-life allows for relatively rapid clearance if side effects necessitate discontinuation
Side Effects
RAD-140
Testosterone suppression (dose-dependent, occurs in virtually all users by week 4-6)
Liver enzyme elevation (ALT, AST increases reported in clinical and anecdotal data)
Hair shedding (temporary, typically resolves after discontinuation)
Headaches (most common in the first 1-2 weeks, often transient)
Nausea (mild, usually with initial doses or on an empty stomach)
Lipid disruption (HDL suppression, LDL elevation)
Mild insomnia or sleep disturbance
Reduced libido and mood changes related to testosterone suppression
YK-11
Liver stress and enzyme elevation (ALT, AST) due to 17-alpha alkylated steroidal structure
Testosterone suppression (dose- and duration-dependent, expected in all users)
Joint dryness and discomfort (related to reduced estrogenic activity and potential drying effect)
Hair shedding (consistent with androgenic activity from the DHT-derived structure; may or may not be reversible)
Lipid disruption (HDL suppression, LDL elevation)
Reduced libido and mood changes secondary to hormonal suppression
Mild headaches, particularly during the first week
Contraindications
Pre-existing liver disease or elevated liver enzymes at baseline
Hormone-sensitive cancers (prostate cancer, certain breast cancers not being treated under clinical supervision)
Pregnancy or potential pregnancy (teratogenic risk from androgen receptor agonism)
Breastfeeding
Age under 25 (incomplete endocrine system maturation and higher risk of HPG axis disruption)
Concurrent use of hepatotoxic medications without medical supervision
Known cardiovascular disease (insufficient safety data for this population)
Pre-existing liver disease or elevated liver enzymes at baseline (17-alpha alkylated compounds are contraindicated in hepatic impairment)
Hormone-sensitive cancers (prostate cancer or other androgen-responsive malignancies)
Pregnancy or potential pregnancy (teratogenic risk from androgen receptor agonism and hormonal disruption)
Breastfeeding
Age under 25 (incomplete endocrine system maturation and higher risk of lasting HPG axis disruption)
Concurrent use of other hepatotoxic compounds or medications (oral steroids, certain NSAIDs, statins, etc.)
Known cardiovascular disease (insufficient safety data)
Research Evidence
RAD-140 YK-11
Status Emerging Limited Research
References 5 studies 4 studies
Latest July 2020 2013
FDA Approved No No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.