SARMs vs Steroids

What Are SARMs?

Selective Androgen Receptor Modulators (SARMs) are a class of synthetic compounds that bind to androgen receptors with tissue-selective activity. The concept was introduced in 1999 — developed with the goal of separating the anabolic effects of androgens (muscle and bone) from androgenic effects (prostate, skin, hair follicles). The theory: a compound that activates androgen receptors in muscle and bone while acting as a weak agonist or antagonist in androgenic tissues would provide the benefits of testosterone without the side effects.

SARMs are nonsteroidal — they are not derived from testosterone and do not share the four-ring carbon structure of AAS. This structural difference is the reason they are not metabolised by 5α-reductase into DHT or aromatised into estrogen — which contributes to a different side effect profile compared to testosterone.

Mechanism — How They Differ

The critical point: while SARMs are designed for tissue selectivity, the selectivity is not complete. All studied SARMs suppress the HPG axis to varying degrees — because any compound activating androgen receptors signals the hypothalamus to reduce LH and FSH output. The degree of suppression varies by compound and dose, but "selective" does not mean "non-suppressive."

Muscle Growth Comparison

This is the dimension where AAS and SARMs differ most dramatically in practice.

Anabolic Steroids — Maximum Anabolic Output

AAS produce powerful anabolism through full androgen receptor agonist activity. A testosterone cycle at 400 mg/week for 10–12 weeks consistently produces 10–20 lbs of lean mass with appropriate training. This is direct, well-documented and reproducible. The anabolic response to AAS is driven by increased protein synthesis, nitrogen retention, IGF-1 upregulation and anti-catabolic effects that work simultaneously across all muscle tissue.

SARMs — Moderate, Compound-Dependent Results

SARMs produce meaningful but more modest anabolic effects. A systematic review of randomised controlled trials published in Clinical Endocrinology (Wen et al., 2024) confirmed that SARMs increase lean body mass and physical performance — but the magnitude is significantly lower than equivalent AAS doses. Typical results from an LGD-4033 cycle: 4–8 lbs of lean mass over 8 weeks at 10 mg/day. Ostarine at 25 mg/day produces more modest recomposition effects.

Testosterone Suppression — The Real Picture

The most common misconception about SARMs is that they do not suppress testosterone. They do — and in some cases, significantly.

SARMs suppress the HPG axis through the same feedback mechanism as AAS: when the hypothalamus detects androgen receptor activation, it reduces GnRH output, which reduces LH and FSH, which reduces testicular testosterone production. The degree of suppression is compound and dose dependent — but all studied SARMs produce measurable suppression at performance-relevant doses.

Side Effects Comparison

A key point on liver toxicity: SARMs were initially assumed to be non-hepatotoxic because they are not 17-alpha alkylated. However, documented cases of severe cholestatic jaundice from SARM use have emerged — and a 2023 review in the Journal of Clinical and Translational Hepatology classified SARMs as an emerging liver toxin. The mechanism differs from 17-aa steroids but the clinical outcome can be equally serious.

SARM Compounds — What Each Does

LGD-4033 (Ligandrol)

LGD-4033 is the most anabolic SARM in common use — the highest lean mass gains per mg of any studied SARM. Originally developed for muscle wasting disease treatment. Strong HPG suppression at performance doses (5–10 mg/day). Requires full SERM PCT — Nolvadex 20 mg/day for 4 weeks minimum.

Ostarine (MK-2866)

Ostarine is the mildest and most studied SARM. Originally developed for muscle and bone wasting. At 10–25 mg/day it produces lean recomposition effects with the lowest suppression of common SARMs. Most appropriate entry-level SARM. Mini-PCT (Nolvadex 20 mg/day × 4 weeks) recommended after 8-week cycles.

MK-677 (Ibutamoren)

MK-677 is grouped with SARMs but is a ghrelin receptor agonist — a GH secretagogue. It does not suppress testosterone and does not require PCT. It produces body recomposition effects through GH/IGF-1 elevation over 3–6 months. Side effects include water retention, increased appetite and potential insulin sensitivity changes at high doses. Safe to run continuously or between AAS/SARM cycles.

S23

S23 is the most suppressive SARM — approaching AAS-level HPG suppression at higher doses. Produces lean, hard gains without water retention. Full SERM PCT required. Not appropriate as a first SARM — consider only after experience with milder compounds.

YK-11

YK-11 has a unique mechanism — it acts as both a partial androgen receptor agonist and a myostatin inhibitor. Myostatin limits muscle growth; inhibiting it theoretically removes this ceiling. YK-11 produces significant strength and lean mass gains. Significant suppression — full PCT required. Limited human safety data even by SARM standards.

PCT for SARMs — What Is Required

PCT after SARM cycles follows the same principles as PCT after AAS cycles — SERMs to restore LH and FSH, bloodwork to confirm recovery.

Full PCT Protocol (LGD-4033, RAD-140, S23, YK-11)

• Wait: 24–48 hours after last SARM dose (SARMs clear faster than long-ester injectables)
• Nolvadex 40 mg/day — weeks 1–2
• Nolvadex 20 mg/day — weeks 3–4
• Or: Clomid 50 mg/day — weeks 1–2, 25 mg/day weeks 3–4
• Or: Enclomiphene 25 mg/day × 4–6 weeks
• Bloodwork 4 weeks post-PCT to confirm testosterone recovery

Mini-PCT Protocol (Ostarine low dose, short cycles)

• Wait: 24 hours after last dose
• Nolvadex 20 mg/day × 4 weeks
• Bloodwork 4 weeks post-PCT

For the complete PCT guide: PCT — Post Cycle Therapy: The Complete Guide.

Cycle Planning — SARMs vs Steroids

When SARMs Make Sense

• First enhancement experience: lower suppression than AAS, oral administration, shorter recovery — appropriate for users who want to assess their response to androgen receptor activation before committing to injectable AAS
• Between AAS cycles: MK-677 (non-suppressive) or low-dose Ostarine can maintain some body composition benefit during off-cycle periods
• Women at very low doses: Ostarine at 5–12.5 mg/day carries lower virilisation risk than most AAS
• Cutting phases: Ostarine or S23 alongside a caloric deficit preserves lean mass without the cardiovascular and hormonal load of full AAS cutting compounds

When Steroids Are the Correct Choice

• Maximum muscle mass: no SARM produces AAS-equivalent anabolic output — if the goal is significant mass gain, testosterone is the tool
• Established users: experienced AAS users have characterised their own response profile and have PCT management dialled in
• Long cycles: AAS — particularly injectables — are better characterised for longer cycles than SARMs

Women — SARMs vs Steroids

For women, SARMs carry lower androgenic risk than most AAS — but they are not risk-free. Virilisation (voice deepening, clitoral enlargement, body hair) is possible at higher SARM doses, particularly with more androgenic compounds like S23 and YK-11.

• Ostarine at 5–12.5 mg/day: the most appropriate SARM for women — lowest androgenicity, meaningful recomposition effects, minimal virilisation risk at these doses
• MK-677 at 12.5–25 mg/day: no androgenic risk — body recomposition and recovery benefits without HPG interaction
• Avoid: S23, RAD-140 and YK-11 at typical male doses — virilisation risk is significant

Women who use AAS typically choose low-androgenicity compounds: Anavar at 5–20 mg/day or Primobolan at low doses. For most women's goals, low-dose Ostarine or MK-677 carry less risk than any AAS.

Frequently Asked Questions