YK-11 is a hybrid compound often classified as a SARM, but in structure it’s actually a modified steroidal molecule that works as a myostatin inhibitor. It significantly increases muscle growth potential by elevating follistatin levels, thereby suppressing myostatin (the protein that puts the brakes on muscle growth). YK-11 is known as one of the most powerful SARMs available, reputed to deliver exceptional muscle hardness and strength gains – it’s sometimes dubbed the “hardener” or compared to DHT in its effects on muscle.
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- Dramatically increases muscle size and strength beyond normal genetic limits (by removing the myostatin cap on muscle growth)
- Known as the most potent SARM for sheer muscle-building – users often experience rapid gains in lean mass when diet and training are on point
- Produces a very dry, hard look to the muscles (no water retention, since it has DHT-like properties, it can increase muscle density and vascularity)
- Promotes enhanced strength and power, making lifts increase notably during a cycle
- May support bone strength similarly to DHT, due to its partial androgenic nature (good for bone mineral density)
- Unique mechanism (myostatin inhibition) means it could be stacked with other SARMs or steroids to break through growth plateaus (additive effect, since other compounds don’t reduce myostatin as YK-11 does)
- Provides fast recovery and muscle fullness; many see improved muscle “pump” and fullness even on low-carb diets or while cutting, courtesy of its anabolic intensity
YK-11 is typically dosed lower than other SARMs due to its strength. A common range is 5–10 mg per day for beginners, and up to 15–20 mg per day for advanced users (often split into two doses due to a shorter half-life around 6–10 hours). This liquid is, say,
10 mg/mL. So:- 5 mg dose = 0.5 mL
- 10 mg dose = 1 mL
- 15 mg dose = 1.5 mL (you might take 0.75 mL in morning, 0.75 mL in afternoon)
Shake the bottle well. Use the dropper to measure and dispense into your mouth, swallow and optionally chase with a flavored drink. Cycle length: 6–8 weeks is typical; YK-11 is somewhat harsher on the body than benign SARMs like Ostarine, so shorter cycles are advised. Because YK-11 is partially steroidal, it can be more suppressive – a full PCT (Nolvadex/Clomid) is definitely recommended after. Liver & Support: There is anecdotal evidence YK-11 can elevate liver enzymes, so consider using a liver support supplement during the cycle. Also ensure adequate water intake and possibly a joint supplement – while YK-11 builds muscle rapidly, tendons and joints may lag behind, and DHT-like compounds can sometimes dry out joints slightly. Timing: If splitting doses, do AM and PM (with ~8 hours between). If taking once daily, take with a meal containing fats for better absorption (being a hydrophobic steroidal compound).
YK-11 is unique – it acts as a partial agonist of the androgen receptor and also increases follistatin levels dramatically. Follistatin is the protein that binds to and inhibits myostatin. Myostatin is the body’s built-in limiter for muscle growth; by suppressing it, YK-11 essentially “takes the brakes off” muscle development. In a famous study, YK-11 treatment of muscle cells in vitro increased follistatin production significantly, and muscle cells grew bigger than with DHT alone. As a result, users can potentially surpass the usual plateau where myostatin would stop further hypertrophy. Meanwhile, because YK-11 is derived from a DHT analog, it has some DHT-like effects – it strongly binds to AR in muscle and bone, acting very anabolic, but without estrogenic action (DHT doesn’t aromatize, and YK-11 in itself doesn’t seem to either). In fact, many compare the muscle hardness on YK-11 to what they feel on Winstrol or other DHT-derived steroids. YK-11 causes muscle cells to increase protein synthesis like other SARMs, but the myostatin inhibition means satellite cells and new muscle fibers can form more freely as well. Essentially, it may unlock new levels of muscle growth by allowing hyperplasia (increase in number of muscle fibers) in addition to hypertrophy (increase in size of existing fibers) – this is something very few compounds can do (only perhaps HGH, etc., aside from YK-11’s mechanism). On the androgenic side, YK-11 is a partial agonist, meaning it doesn’t fully activate the androgen receptor as strongly as DHT would, which might limit some side effects in androgen-sensitive tissues, but nonetheless it is notable for being harsher than typical SARMs in terms of suppression and potential side effects (some users report mild hair shedding or joint dryness – signs of androgenic activity – at higher doses). YK-11’s half-life is relatively short, hence splitting doses can keep levels more stable. It doesn’t convert to estrogen, and may actually lower estrogen indirectly by suppressing endogenous test (leading to less aromatization overall during cycle). So one must watch for low estrogen symptoms like joint discomfort or low libido – ironically, even though it’s super anabolic, without some estrogen you might feel a bit off; stacking with a mild aromatizing compound or keeping an eye on estradiol is wise. YK-11 being steroidal might impact the liver as mentioned, likely via its steroid-like structure – it’s not 17-alkylated, but caution is warranted. Summing up: YK-11 builds muscle by two avenues – direct AR activation (like a powerful SARM) plus blocking myostatin’s muscle growth limitation (via follistatin upregulation). This dual action makes it extremely potent but also demands respect regarding side effect management.
30 mL dropper bottle (liquid solution, 20 mg/mL).
YK-11 can pack on muscle quickly; experienced users often save it for plateaus or to push past natural limits. Gains of 5-8 lbs of lean mass in 6 weeks are not unusual (with diet/training dialed in), with a concurrent drop in fat due to the recomposition effects. Side effects to monitor: Aggression can spike due to the DHT nature – some feel more short-tempered on it (though many channel that to workouts). Hair follicles: if prone to male pattern baldness, YK-11 might accelerate hair loss (again, DHT-like effect on scalp). Joint dryness or pain – because it’s like DHT, it can reduce collagen synthesis or dry joints (if this occurs, ensure you have adequate Omega-3s, perhaps supplement collagen, and avoid heavy one-rep max lifting that could strain connective tissue). Cholesterol could skew (as with many anabolic compounds) – often HDL goes down, LDL up a bit. Liver enzymes might rise modestly; keep cycles short and avoid alcohol or other liver stressors concurrently. Suppression: YK-11 is definitely suppressive – incorporate a solid PCT (e.g., Nolva 40/40/20/20) to recover. Many users anecdotally compare YK-11’s feel to a mild Winstrol + myostatin inhibitor in one – high praise, but also a warning that it’s not a casual SARM for beginners. For a first cycle, something like Ostarine or LGD is gentler; YK-11 is more for advanced users or those who have done multiple SARM/steroid cycles. Stacking: People sometimes stack YK-11 with LGD-4033 or RAD-140 for insane bulks, or with Ostarine/Cardarine for recomps. If stacking, doses should be on lower side because synergy can amplify both results and sides. Sex: YK-11 is not recommended for women – virilization risk is quite high due to its potent androgenic actions (it’s basically a designer steroid in some respects). Women who want myostatin inhibition might consider other experimental pathways or very, very low dose if at all (but generally, avoid). In conclusion, treat YK-11 with the respect you’d give an oral steroid: cycle support, liver care, PCT, and diligent monitoring of your body’s responses.
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