SARMs Explained: LGD-4033, YK-11, S-4, and RAD-140 — Which SARM Is Right for Your Goals?

Selective Androgen Receptor Modulators have redefined what is possible in legal performance enhancement. Unlike classical anabolic steroids, SARMs are designed to activate androgen receptors selectively in muscle and bone tissue while minimizing activity in the prostate, liver, and skin — theoretically delivering anabolic benefits with a reduced androgenic burden.

Theory is one thing. Real-world results are another. Here is a comprehensive breakdown of every SARM we stock, their unique mechanisms, realistic results, and how to match them to your goals.

What Makes SARMs Different From Steroids?

Classical testosterone and its derivatives are non-selective. They activate androgen receptors in every tissue that expresses them. SARMs achieve tissue selectivity through their molecular shape and binding characteristics, which differ across receptor subtypes and co-regulators—the result: anabolic effects concentrated in skeletal muscle, with attenuated activity in androgenic tissues.

Note that “selective” does not mean “without side effects.” All SARMs produce dose-dependent testosterone suppression by signaling the hypothalamus and pituitary to reduce LH and FSH output. PCT remains necessary after any SARM cycle.

LGD-4033 (Ligandrol) — The Gold Standard Bulking SARM

Overview

Ligand Pharmaceuticals originally developed LGD-4033 to treat muscle wasting and osteoporosis. It is the most well-researched SARM with multiple Phase I clinical trials completed. Its high affinity for the androgen receptor makes it exceptionally potent for anabolic stimulus.

Benefits

• Strong lean mass accumulation — the most anabolic SARM per milligram
• Significant strength gains, particularly in compound lifts
• Moderate improvement in bone density
• Does not aromatize — no estrogen-related side effects

Dosing

• Beginner: 5mg/day
• Intermediate: 10mg/day
• Cycle length: 8 weeks recommended

Side Effects

LGD-4033 suppresses testosterone significantly. A Boston University clinical trial found LH and FSH suppression even at 1mg/day. At recreational doses (5-10mg), bloodwork consistently shows suppression. HDL cholesterol may be moderately reduced. Liver enzyme elevation has been reported in rare cases at high doses.

Ideal For

Lean bulking cycles. Users who want maximum anabolic stimulus without injectable testosterone.

YK-11 — The Myostatin Inhibitor SARM

Overview

YK-11 is the most unique and potent compound in the SARM category. While it does bind the androgen receptor, its most clinically significant action is myostatin inhibition. Myostatin is a protein that limits muscle growth — essentially a biological cap on how much muscle your body can build. By inhibiting myostatin, YK-11 theoretically unlocks muscle growth potential beyond normal physiological limits.

Benefits

• Exceptional muscle fullness and density
• May allow gains beyond natural or even standard SARM-achievable limits
• Strong synergy with LGD-4033 in bulking stacks
• Significant strength increases

Dosing

• Typical range: 5-10mg/day
• Cycle length: 6-8 weeks (more cautious approach recommended due to limited clinical data)

Side Effects

YK-11 has limited human clinical data compared to LGD-4033. Anecdotal evidence suggests it is more suppressive than other SARMs and may have mild androgenic activity. Some users report joint discomfort. Liver stress has been noted at higher doses. This is not a beginner compound.

Ideal For

Intermediate to advanced users looking to break through muscle growth plateaus. Best run as part of a stack rather than solo.

S-4 (Andarine) — The Lean Cutting SARM

Overview

S-4 was originally developed by GTX Inc. for muscle wasting, osteoporosis, and benign prostate hyperplasia. In the performance community, it has carved out a specific niche as the premier SARMs cutting and hardening compound, particularly in the final weeks before a competition or photoshoot.

Benefits

• Pronounced muscle hardening and vascularity
• Preserves lean tissue during caloric deficit
• Mild fat loss properties
• Faster onset compared to LGD-4033 — effects noticeable by week 2

Dosing

• Typical range: 25-50mg/day (split dosing recommended due to shorter half-life)
• Cycle length: 8 weeks; many users run 5 days on, 2 days off to mitigate vision effects

Side Effects

S-4’s primary notable side effect is vision alteration — specifically a yellowish or greenish tint to vision in low-light conditions and reduced night vision acuity. This is caused by S-4’s activity at retinal androgen receptors and is dose-dependent and fully reversible upon discontinuation. Suppression is milder than LGD-4033 at equivalent doses.

Ideal For

Cutting cycles, pre-competition preparation, and stacking with LGD-4033 for a complete recomposition protocol.

Stacking SARMs: Optimal Combinations

Lean Bulk Stack

• LGD-4033 10mg/day + YK-11 5mg/day — 8 weeks
• Most powerful mass-building SARM combination available
• Requires aggressive PCT due to combined suppression

Recomposition Stack

• LGD-4033 5mg/day + S-4 50mg/day — 8 weeks
• Combines mass-building (LGD) with hardening and fat loss (S-4)
• Moderate suppression

Cutting Stack

• S-4 50mg/day + Winstrol 20mg/day — 6-8 weeks
• Maximum muscle hardening and definition
• Add Clenbuterol for additional fat oxidation

PCT After SARMs

All SARMs in our catalog are suppressive. After any SARM cycle of 6 weeks or more, a proper PCT protocol is required. Our recommended protocol:

• HCG 5000IU: 500IU every other day for 2 weeks (begin 24-48 hours after last SARM dose)
• SERM for 4 weeks following the HCG phase

Bloodwork at 6 weeks post-PCT is essential to confirm HPTA recovery.