SARMs: The Complete Guide to Selective Androgen Receptor Modulators (2026)

Selective Androgen Receptor Modulators — SARMs — represent a class of compounds designed to activate androgen receptors in muscle and bone tissue while minimizing activation in organs like the prostate, liver, and sebaceous glands. This tissue selectivity is their defining advantage over traditional anabolic steroids, which activate androgen receptors indiscriminately throughout the body.

The concept is straightforward: deliver the muscle-building and bone-strengthening effects of androgens without the prostate enlargement, hair loss, acne, and liver toxicity associated with steroids. In practice, selectivity exists on a spectrum — some SARMs are highly selective (Ostarine), while others approach steroid-level potency and suppression (S-23, YK-11).

Originally developed by pharmaceutical companies for conditions like muscle wasting, osteoporosis, and cachexia, SARMs entered the performance enhancement world in the early 2010s. Today, they occupy a middle ground between natural supplements (which do little) and anabolic steroids (which do a lot but carry significant risk). For Canadian researchers and athletes, SARMs offer a risk-adjusted performance option — more effective than supplements, less disruptive than steroids.

This hub covers every SARM available through Novo Pharma, with mechanisms, comparisons, and links to in-depth individual articles.

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How SARMs Work: Mechanism of Action

Traditional androgens (testosterone, DHT) bind androgen receptors in every tissue they reach — muscle, bone, prostate, skin, liver, brain. SARMs are engineered to preferentially bind androgen receptors in specific tissues through conformational selectivity. When a SARM binds the androgen receptor, it induces a different receptor conformation than testosterone does, recruiting different coactivator and corepressor proteins depending on the tissue type.

In muscle and bone: SARMs recruit anabolic coactivators → gene transcription → protein synthesis and bone mineralization.

In prostate and skin: SARMs recruit fewer androgenic coactivators → reduced DHT-like effects → less prostate growth, less sebum production, less hair follicle miniaturization.

This selectivity is never absolute. At higher doses, even selective SARMs begin producing androgenic effects. The dose-response relationship determines the practical selectivity window.

Additionally, several compounds commonly grouped with SARMs (MK-677, Cardarine, SR-9009) are not technically SARMs — they do not bind androgen receptors at all. They are grouped here by convention because they are sold alongside SARMs and commonly stacked with them.

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All 12 SARMs Compounds

RAD-140 (Testolone)

RAD-140 is the most potent SARM for lean muscle gain. Developed by Radius Health for breast cancer and muscle wasting, it demonstrates an anabolic:androgenic ratio of approximately 90:1 (compared to testosterone's 1:1). Users report strength gains comparable to low-dose testosterone cycles — 10-15 lbs of lean tissue in 8 weeks is commonly reported at 10-20mg daily. RAD-140 is suppressive; PCT is recommended for cycles exceeding 6 weeks.

Best for: Bulking, strength, lean mass gains.

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MK-677 (Ibutamoren)

MK-677 is not a SARM — it is an oral growth hormone secretagogue (ghrelin mimetic). It elevates GH and IGF-1 levels by mimicking the hunger hormone ghrelin at the pituitary. Included in the SARMs category by market convention. MK-677 increases appetite, improves sleep depth, enhances recovery, and produces measurable increases in lean mass and fat loss over 3-6 month periods. It is non-suppressive to testosterone and requires no PCT.

Best for: Recovery, sleep, anti-aging, stacking with suppressive SARMs.

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YK-11

YK-11 is a synthetic steroidal compound that acts as both a partial androgen receptor agonist and a myostatin inhibitor. It is the only SARM that inhibits myostatin — the protein that limits muscle growth. By both activating anabolic pathways AND removing growth limitations, YK-11 produces dramatic muscle-building effects. However, its steroidal structure means it is liver-methylated and suppressive. Treat it as closer to an oral steroid than a traditional SARM.

Best for: Advanced users seeking maximum muscle growth beyond natural limitations.

[Internal Link: /blog/yk-11-myostatin-inhibitor-guide/] [Internal Link: /product/yk-11/]

SR-9009 (Stenabolic)

SR-9009 is a Rev-ErbA agonist — not a SARM — that modulates circadian rhythm genes controlling metabolism. It increases mitochondrial count in muscle, enhances glucose and lipid metabolism, and improves exercise capacity. SR-9009 mimics the metabolic effects of exercise at a cellular level. Its major limitation is poor oral bioavailability (approximately 2%), which has led to sublingual and injectable formulations. Non-suppressive.

Best for: Endurance, fat loss, metabolic enhancement.

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LGD-4033 (Ligandrol)

LGD-4033 is the second most popular SARM for bulking after RAD-140. Developed by Ligand Pharmaceuticals, clinical trials demonstrated 1.21 kg of lean mass gain at just 1mg/day over 21 days with no fat gain. At research doses (5-10mg), LGD-4033 produces consistent 6-10 lb lean tissue gains in 8-week cycles. More suppressive than Ostarine but less than RAD-140. Produces a fuller, wetter look than RAD-140 due to mild water retention.

Best for: Lean bulking with a fuller look, strength gains.

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Ostarine (MK-2866 / Enobosarm)

Ostarine is the most researched and mildest SARM available. With three Phase III clinical trials completed for muscle wasting, it has the most human safety data. At 12.5-25mg daily, Ostarine preserves muscle during caloric deficit, produces modest lean gains (3-6 lbs in 8 weeks), and enhances recovery. Its mild suppression profile means many users run it without PCT for cycles under 8 weeks. The ideal first SARM.

Best for: Cutting (muscle preservation), beginners, injury recovery, women.

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Cardarine (GW-501516)

Cardarine is a PPARδ receptor agonist — not a SARM — that dramatically enhances fatty acid oxidation and endurance capacity. Developed by GlaxoSmithKline, it was abandoned after animal studies showed cancer at extreme doses (the relevance to human use at research doses is debated extensively). Cardarine allows the body to preferentially burn fat for fuel, increases exercise endurance by 50-70% in studies, and improves lipid profiles. Non-suppressive, non-hormonal.

Best for: Fat loss, endurance, improving lipid panels (HDL/LDL ratio).

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S-23

S-23 is the most potent and most suppressive SARM available. Developed by GTx as a potential male hormonal contraceptive (it suppresses FSH and LH to near-zero), S-23 produces steroid-level muscle hardening and fat loss. It binds the androgen receptor with the highest affinity of any SARM. S-23 should be treated as an oral steroid — full PCT with testosterone base is strongly recommended. Not for beginners.

Best for: Advanced cutting, muscle hardening, contest prep (experienced users only).

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ACP-105

ACP-105 is a partial androgen receptor agonist developed by Acadia Pharmaceuticals. It demonstrates approximately 66% of the anabolic potency of testosterone with only partial suppression of the HPG axis. ACP-105 is significantly milder than RAD-140 or LGD-4033, making it suitable for conservative users, women, and those prioritizing minimal side effects over maximum gains. Think of it as a lighter LGD-4033.

Best for: Conservative bulking, women, those sensitive to suppression, stacking.

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S-4 (Andarine)

S-4 was one of the first SARMs developed, by GTx Inc. for osteoporosis and muscle wasting. It produces moderate lean mass gains and notable fat loss, with a unique cosmetic effect — muscular hardening and vascularity. Its signature side effect is temporary vision disturbance (yellow tint, difficulty adjusting to dark) caused by binding retinal receptors. This side effect is dose-dependent and fully reversible upon discontinuation.

Best for: Cutting, recomposition, cosmetic hardening (accept vision side effect).

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GW-0742

GW-0742 is a second-generation PPARδ agonist, structurally related to Cardarine (GW-501516) but with higher potency and selectivity for PPARδ over PPARα and PPARγ. It offers similar fat-burning and endurance benefits to Cardarine with potentially improved safety margins. GW-0742 also demonstrates anti-inflammatory properties in research. Non-suppressive and non-hormonal — stacks seamlessly with any SARM or steroid cycle.

Best for: Fat oxidation, endurance, inflammation reduction, stacking.

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AC-262536

AC-262536 is a non-steroidal SARM with approximately 66% of testosterone's anabolic effect and only 27% of its androgenic effect — yielding a 2.45:1 anabolic:androgenic ratio. Developed by Acadia Pharmaceuticals alongside ACP-105, it is a mild, well-tolerated compound suitable for beginners and users seeking gradual gains with minimal side effects. Suppression is dose-dependent but generally mild at research doses (10-20mg).

Best for: Beginners, long-cycle conservative gains, those cautious about suppression.

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SARMs Comparison Table

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SARMs for Different Goals

SARMs for Bulking

The bulking tier prioritizes lean mass and strength:

1. RAD-140 (10-20mg) — Maximum lean gains, best strength increase
2. LGD-4033 (5-10mg) — Fuller look, consistent mass gains
3. YK-11 (5-10mg) — Most dramatic results (advanced only)
4. MK-677 (25mg) — Stack with any of the above for enhanced recovery and GH

A typical bulking stack: RAD-140 15mg + MK-677 25mg for 8 weeks, followed by PCT.

[Internal Link: /blog/best-sarms-bulking-stack/]

SARMs for Cutting

The cutting tier preserves muscle while accelerating fat loss:

1. Ostarine (12.5-25mg) — Muscle preservation in deficit
2. Cardarine (10-20mg) — Fat oxidation + endurance
3. SR-9009 (20-30mg split doses) — Metabolic enhancement
4. S-23 (10-15mg) — Hardening + fat loss (advanced)

A typical cutting stack: Ostarine 20mg + Cardarine 15mg for 8 weeks. No PCT usually needed.

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SARMs for Recomposition

Recomposition — gaining muscle while losing fat simultaneously:

1. RAD-140 (10-15mg) — Lean gains even in slight deficit
2. Cardarine (15-20mg) — Fuel partitioning toward fat oxidation
3. S-4 (50mg) — Simultaneous hardening + fat loss
4. LGD-4033 (5mg) + Cardarine (15mg) — Moderate approach

[Internal Link: /blog/best-sarms-recomp-stack/]

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SARMs for Women

Women respond to SARMs at significantly lower doses due to naturally lower androgen levels. The key concern is virilization — developing masculine characteristics (voice deepening, facial hair, clitoral enlargement). Compound selection is critical.

Recommended for women:

• Ostarine (5-12.5mg) — The safest SARM for women. Muscle preservation, mild lean gains, no virilization reports at these doses.
• Cardarine (10-15mg) — Non-hormonal, zero virilization risk. Pure fat loss and endurance.
• ACP-105 (5mg) — Partial agonist, mild enough for female use.
• MK-677 (12.5-25mg) — Non-hormonal GH secretagogue, safe for long-term female use.

Avoid:

• RAD-140, LGD-4033, S-23, YK-11 — Too potent/suppressive for female hormonal balance.

[Internal Link: /blog/sarms-for-women-guide/]

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PCT Requirements by Compound

No PCT Needed

• MK-677 (non-hormonal)
• Cardarine (non-hormonal)
• SR-9009 (non-hormonal)
• GW-0742 (non-hormonal)

PCT Optional (Short Cycles <8 Weeks)

• Ostarine (mild suppression, self-recovers in 2-4 weeks)
• ACP-105 (partial agonist, minimal suppression)
• AC-262536 (mild, recovers quickly)

PCT Recommended

• RAD-140 (significant LH/FSH suppression at 15mg+)
• LGD-4033 (dose-dependent, suppressive at 10mg for 8+ weeks)
• S-4 (moderate suppression with extended use)
• YK-11 (steroidal, expect full suppression)

PCT Required (Full Protocol)

• S-23 (near-complete HPTA suppression, treat like oral steroid)

Standard SARM PCT Protocol: Nolvadex 20mg/day for 4 weeks, starting the day after last SARM dose (no waiting period — SARMs clear quickly).

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SARMs vs Steroids: Key Differences

SARMs are not "steroids lite" — they are a fundamentally different pharmacological approach. Choose SARMs when you want moderate enhancement with manageable sides. Choose steroids when you accept full hormonal manipulation for maximal results.

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How to Use SARMs: Practical Guide

Dosing and Timing

Most SARMs are dosed once daily due to their relatively long half-lives (12-60 hours). Compounds with shorter half-lives (S-4, SR-9009, ACP-105) benefit from split dosing — dividing the daily amount into 2-3 administrations for more stable blood levels. Take SARMs at the same time each day for consistency.

SARMs can be taken with or without food — oral bioavailability is generally not affected by stomach contents (unlike some peptides that require fasting). Exception: MK-677 is preferably taken before bed to align its GH-releasing effects with natural nocturnal GH pulsatility and to sleep through the appetite-stimulating effects.

Cycle Length

Standard SARM cycles range from 6-12 weeks depending on the compound and goal:

• Mild SARMs (Ostarine, ACP-105, AC-262536): 8-12 weeks safely
• Potent SARMs (RAD-140, LGD-4033): 8-10 weeks recommended
• Very potent SARMs (S-23, YK-11): 6-8 weeks maximum
• Non-suppressive compounds (MK-677, Cardarine, SR-9009, GW-0742): Can be run 12-16+ weeks

Extending beyond recommended lengths increases suppression without proportional gains — the androgen receptor downregulates with chronic activation.

Blood Work Protocol for SARMs

Pre-cycle blood work (baseline):

• Total and free testosterone
• LH, FSH
• Estradiol (sensitive assay)
• Complete blood count
• Liver enzymes (AST, ALT) — particularly for YK-11
• Lipid panel (LDL, HDL, triglycerides)

Mid-cycle (week 4-5):

• Testosterone, LH, FSH (assess suppression level)
• Liver enzymes if using YK-11 or S-23

Post-PCT (4-6 weeks after completing any PCT):

• Full hormone panel confirming recovery
• Lipid panel confirming normalization

Common Mistakes to Avoid

1. Stacking multiple suppressive SARMs — RAD-140 + LGD-4033 doubles suppression without doubling results (same receptor)
2. Extending cycles to chase more gains — weeks 10-12 rarely add meaningful tissue but significantly extend recovery
3. Skipping PCT after suppressive cycles — "I feel fine" is not blood work. Draw blood.
4. Starting too high — begin at the LOW end of the dosing range. You can always increase in your next cycle.
5. Using SARMs to replace training/nutrition fundamentals — compounds amplify stimulus, they do not replace it

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Legal Status of SARMs in Canada

SARMs are not scheduled under Canada's Controlled Drugs and Substances Act (CDSA). They are not anabolic steroids and do not fall under Schedule IV. However, they are also not approved by Health Canada as therapeutic drugs — meaning they cannot legally be sold for human consumption as medicines.

In practice, SARMs are sold as "research chemicals" or "reference standards" in Canada. This means:

• Legal to purchase for research purposes
• Legal to possess in any quantity
• Not legal to sell as dietary supplements or medicines with health claims
• No import restrictions for personal quantities
• No criminal penalties for possession or purchase

This regulatory position differs significantly from anabolic steroids (Schedule IV — illegal to traffic, legal to possess) and from the United States (where SARMs are banned in dietary supplements by the SARMs Control Act of 2018 but remain available as research chemicals).

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Frequently Asked Questions

Are SARMs safe?

SARMs are safer than anabolic steroids by design — tissue selectivity reduces off-target effects. However, "safer" does not mean "safe." Long-term human safety data is limited since no SARM has completed full regulatory approval. Known risks include hormonal suppression (reversible), potential liver stress (particularly YK-11 and S-23), and unknown long-term consequences. Blood work before, during, and after a cycle is essential for monitoring.

How quickly do SARMs work?

Most users notice strength increases within the first 1-2 weeks. Visible body composition changes appear by weeks 3-4. Full results manifest at the 6-8 week mark. Compounds with shorter half-lives (S-4, SR-9009) reach steady-state faster but require split dosing. MK-677 produces noticeable sleep improvement within 2-3 days.

Can I stack SARMs with steroids?

Yes. SARMs can complement steroid cycles — Ostarine during PCT to preserve gains, Cardarine for endurance during any cycle, MK-677 year-round for GH optimization. However, stacking suppressive SARMs (RAD-140, LGD-4033) ON TOP of a steroid cycle provides diminishing returns since androgen receptors are already saturated. The most strategic use is during bridges or PCT.

Do SARMs show up on drug tests?

Yes. WADA (World Anti-Doping Agency) tests for all SARMs. Detection windows vary: Ostarine 9-28 days, LGD-4033 up to 22 days, RAD-140 up to 24 days. MK-677 and Cardarine are also prohibited and tested for. If you compete in tested sports, all compounds in this guide are banned regardless of their legal status.

What is the best first SARM cycle?

Ostarine 15mg/day for 8 weeks. It provides meaningful results (muscle preservation or mild gain), minimal side effects, optional PCT, and teaches you how your body responds to androgen receptor modulation. Graduate to RAD-140 or LGD-4033 for your second cycle if you want more potent effects.

[Internal Link: /blog/first-sarm-cycle-guide/]

Can women take SARMs?

Yes, with compound selection. Ostarine (5-12.5mg), Cardarine (10-15mg), ACP-105 (5mg), and MK-677 (12.5-25mg) are appropriate for women. Avoid RAD-140, LGD-4033, S-23, and YK-11 due to virilization risk. Women generally do not need PCT after SARM cycles as their hormonal recovery is different from men's.

[Internal Link: /blog/sarms-for-women-guide/]

How do I verify my SARMs are legitimate?

Third-party testing via HPLC (High-Performance Liquid Chromatography) is the gold standard. Reputable sources provide certificates of analysis for each batch. Signs of underdosed or fake SARMs: no effects at known-effective doses, unexpected side effects (suggesting prohormone substitution), and absence of COA documentation.

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SARMs Source Quality: What to Look For

The SARMs market is plagued by underdosed, mislabeled, and substituted products. Independent testing studies have repeatedly found that a significant percentage of commercially available SARMs do not contain what the label claims. Some contain prohormones instead, some are dramatically underdosed, and some contain nothing at all.

Third-Party Testing

The gold standard for verification is High-Performance Liquid Chromatography (HPLC) testing by an independent laboratory. A legitimate Certificate of Analysis (COA) should include:

• Date of testing
• Batch/lot number matching your product
• Laboratory name and accreditation
• Compound identity confirmation
• Purity percentage (target: 98%+ for research-grade)
• Absence of heavy metals, solvents, and microbial contamination

Red Flags for Fake SARMs

• No COA available upon request
• Immediate dramatic results suggesting prohormone substitution (especially if liver stress markers spike — real SARMs other than YK-11 are gentle on the liver)
• Side effects inconsistent with the stated compound (gynecomastia from "Ostarine" suggests a testosterone prohormone)
• Capsules instead of liquid (capsules are easier to adulterate without visible indicators)
• Extremely low pricing compared to verified sources (raw materials have real floor costs)

How to Self-Verify

If you suspect your SARMs are not what is claimed:

1. Note any unexpected side effects or unusually dramatic results
2. Get blood work at week 3-4: if testosterone is completely suppressed on a "mild" Ostarine cycle at 15mg, something stronger is in the product
3. Check liver enzymes: significant ALT/AST elevation suggests an oral steroid or prohormone substitution (real Ostarine, RAD-140, and LGD-4033 do not meaningfully elevate liver markers at standard doses)

[Internal Link: /blog/sarms-quality-verification/]

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Conclusion

SARMs occupy a unique position in performance enhancement — more effective than natural alternatives, more targeted than steroids, and legally accessible in Canada. Their tissue selectivity offers a genuine pharmacological advantage for those seeking androgen-mediated benefits without systemic androgenic consequences.

The key to successful SARM use is matching compound to goal: Ostarine for preservation and entry-level gains, RAD-140 or LGD-4033 for serious bulking, Cardarine for fat loss and endurance, and S-23 or YK-11 only for advanced users who understand the risk profile.

Always run blood work. Always have PCT on hand. And always start with the mildest effective dose before escalating.

Explore each compound's dedicated article for dosing protocols, cycle examples, bloodwork interpretation, and stacking strategies.

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