SARMs — What They Are and How They Differ from Steroids Selective Androgen Receptor Modulators (SARMs) are compounds designed to activate androgen receptors in a tissue-selective manner — anabolic effects in muscle and bone with theoretically reduced androgenic effects elsewhere. In practice, selectivity is partial — all SARMs suppress testosterone, impact lipids and carry health risks. They are not a safe alternative to steroids; they are a different risk-benefit profile. See the full evidence-based comparison: SARMs vs Steroids — The Complete Guide. SARMs require PCT. All SARMs suppress the HPG axis through androgen receptor activation. LGD-4033, S23 and YK-11 cause significant suppression requiring full SERM PCT. Ostarine at low doses causes milder suppression. MK-677 is not a SARM and does not suppress testosterone. See: PCT — Post Cycle Therapy. SARMs by Compound LGD-4033 — Ligandrol LGD-4033 is the most anabolic SARM available — the highest lean mass gain of any SARM in human clinical trials. 5–10 mg/day for 8 weeks. Significant testosterone suppression — full PCT required (Nolvadex 40/40/20/20 or Enclomiphene 25 mg/day for 4–6 weeks). Lipid impact moderate. Detection window: 3–4+ weeks. Best for: lean bulking, strength improvement. MK-2866 — Ostarine (Enobosarm) Ostarine is the mildest and most studied SARM. Phase II clinical trial data exists for muscle wasting conditions. 10–25 mg/day for 8 weeks. Lower suppression than LGD-4033 at standard doses — mini-PCT (Nolvadex 20 mg/day for 4 weeks) typically sufficient. Useful for body recomposition, joint support and as a first SARM. Women's option at 5–10 mg/day. MK-677 — Ibutamoren MK-677 is grouped with SARMs but is not one — it is a ghrelin receptor agonist (GH secretagogue). It does not bind androgen receptors, does not suppress testosterone and does not require PCT. Oral, once daily. 25 mg/day — elevates GH and IGF-1 for body recomposition, improved sleep quality, lean mass support and fat loss. Can be used continuously without cycling. No detection method concerns regarding testosterone suppression. S23 — Mastorin S23 is the most potent and most suppressive SARM available — comparable to mild androgenic steroids in both effect and suppression. 10–30 mg/day for 8 weeks. Dry, hard lean mass gains with significant fat loss. Full PCT mandatory — suppression is severe and testosterone recovery without PCT is slow. Best used by experienced SARM users who have already run LGD-4033 or similar. Detection window: 3–5+ weeks. YK-11 — Myostatin Inhibitor YK-11 is structurally a steroidal SARM — it activates androgen receptors AND inhibits myostatin, the protein that limits muscle growth. This dual mechanism produces lean mass and strength gains beyond what standard SARMs achieve. 5–10 mg/day for 8 weeks. Significant suppression — full PCT required. Hepatotoxicity concerns due to its steroidal structure. Detection window: 3–4+ weeks. Compound Goal Dose Suppression PCT Required LGD-4033 Lean bulk 5–10 mg/day Significant Full SERM PCT Ostarine Recomp / joint 10–25 mg/day Mild–Moderate Mini-PCT MK-677 GH/IGF-1 support 25 mg/day None Not required S23 Dry lean mass 10–30 mg/day Severe Full SERM PCT YK-11 Lean mass + strength 5–10 mg/day Significant Full SERM PCT PCT compounds for SARMs: Nolvadex, Clomid and Enclomiphene are all available at Steroid Warehouse. For SARMs with significant suppression, start PCT 24–48 hours after last dose (SARMs clear faster than most AAS). Full suppression guide: Will Steroids Shut Down Testosterone? Frequently Asked Questions Are SARMs safer than anabolic steroids? ＋ In some dimensions yes — no aromatisation, no DHT conversion, no injectable administration. But SARMs suppress testosterone, impact lipids and some have documented hepatotoxicity. Long-term human safety data is significantly thinner than for testosterone. They are not a side-effect-free alternative — they are a different risk profile. Full comparison: SARMs vs Steroids. Do SARMs require PCT? ＋ Yes — all SARMs that bind androgen receptors suppress testosterone. LGD-4033, S23 and YK-11 cause significant suppression requiring full SERM PCT. Ostarine at low doses causes milder suppression — mini-PCT (Nolvadex 20 mg/day for 4 weeks) typically sufficient. MK-677 is not a SARM and does not suppress testosterone — no PCT required. What is the best SARM for beginners? ＋ Ostarine (MK-2866) at 10–15 mg/day is the most commonly recommended first SARM — lowest suppression, most clinical data, mild side effect profile. LGD-4033 is the next step for more significant lean mass gains. S23 and YK-11 are advanced compounds not recommended as first SARMs. MK-677 can be stacked with any SARM without adding suppression. Is MK-677 a SARM? Does it suppress testosterone? ＋ No — MK-677 (Ibutamoren) is a ghrelin receptor agonist and GH secretagogue. It does not bind androgen receptors, does not suppress testosterone and does not require PCT. It is grouped with SARMs for marketing reasons but works through a completely different mechanism — elevating GH and IGF-1 rather than activating androgen receptors. Are SARMs detectable in drug tests? ＋ Yes — WADA has validated detection methods for all major SARMs including LGD-4033, Ostarine, S23 and YK-11. Detection windows range from 3–5+ weeks in urine. The idea that SARMs are undetectable is completely outdated — it has not been accurate since approximately 2015. Full detection guide: Steroid Detection Times.