Learn about commonly used compounds, their benefits, side effects, and proper administration protocols.
Warning: This information is for educational purposes only. Not medical advice.
Always consult a healthcare professional before starting any new protocol. Get bloodwork regularly.
Injectable L-Carnitine bypasses the severe bioavailability limitations of oral carnitine supplementation. Oral L-Carnitine has only 5-18% absorption, meaning most of a 2-3g oral dose is wasted and metabolized by gut bacteria into TMAO (a cardiovascular risk marker). Injectable L-Carnitine delivers 100% bioavailability directly into the bloodstream, allowing meaningful increases in muscle carnitine content. L-Carnitine plays a critical role in fatty acid transport into mitochondria for beta-oxidation, androgen receptor upregulation, and exercise recovery. For AAS users, injectable L-Carnitine is particularly valued for its ability to increase androgen receptor density, potentially amplifying the effects of exogenous testosterone and other androgens.
Amino acid derivative that enhances fat oxidation and androgen receptor density.
Berberine is an isoquinoline alkaloid extracted from several plants including Berberis, Goldenseal, and Oregon Grape. It has gained significant attention as a natural alternative to Metformin for insulin sensitization and blood glucose management. Multiple clinical trials have demonstrated that berberine lowers fasting blood glucose, HbA1c, and improves insulin sensitivity comparably to Metformin at standard doses. For PED users, berberine serves as an over-the-counter option for managing AAS-induced insulin resistance, GH-related hyperglycemia, and improving nutrient partitioning — all without requiring a prescription.
Powerful retinoid that eliminates severe acne by shrinking sebaceous glands.
Antiparasitic medication with broad-spectrum activity and studied anti-inflammatory properties.
Metformin is a biguanide oral anti-diabetic medication and arguably the most well-studied drug in the world for metabolic health, insulin sensitivity, and longevity. For bodybuilders and PED users, Metformin serves multiple purposes: improving insulin sensitivity (which AAS and growth hormone can impair), enhancing nutrient partitioning toward muscle rather than fat, managing blood glucose on GH/insulin protocols, and providing potential longevity benefits through AMPK activation. It is the go-to pharmaceutical for managing the metabolic side effects of AAS use, particularly during bulking phases where excess caloric intake combined with hormonal changes can promote insulin resistance.
Milk Thistle (Silybum marianum) is a flowering plant whose seeds contain a complex of flavonolignans collectively known as silymarin. The most active component is silybin (silibinin), which comprises 50-70% of the silymarin complex. Milk Thistle has been used for liver support for over 2,000 years and is the most popular liver supplement worldwide. For steroid users, it provides a baseline level of hepatoprotection through antioxidant, anti-inflammatory, and hepatocyte-regenerative mechanisms. However, it is important to understand that Milk Thistle alone is NOT sufficient liver protection for oral steroid cycles — it should be used as part of a comprehensive stack with NAC and TUDCA rather than as a standalone protectant.
Powerful antioxidant and glutathione precursor essential for liver protection during oral steroid use.
N-Acetyl Cysteine (NAC) is the acetylated form of the amino acid L-cysteine and the single most important liver support supplement for anyone using oral anabolic steroids. It is the direct precursor to glutathione — the body's master antioxidant and the primary molecule responsible for hepatic detoxification of methylated (17-alpha-alkylated) oral steroids. NAC is also used clinically as the standard treatment for acetaminophen (Tylenol) overdose-induced liver failure, demonstrating its powerful hepatoprotective capacity. For steroid users, NAC is considered essential during any oral steroid cycle and highly recommended as general health support year-round.
Cardioselective beta-blocker with vasodilating properties for blood pressure and heart rate control.
Serotonin 5-HT3 antagonist that effectively prevents nausea and vomiting.
PDE5 inhibitor for erectile function and blood flow enhancement with shorter duration than tadalafil.
Long-acting PDE5 inhibitor for erectile function, blood pressure, and improved blood flow.
ARB blood pressure medication with PPAR-gamma activation for cardio and metabolic benefits.
Tauroursodeoxycholic acid (TUDCA) is a water-soluble bile acid and the most potent liver support compound available for oral steroid users. It is the taurine conjugate of ursodeoxycholic acid (UDCA), with superior bioavailability and efficacy. TUDCA protects the liver through a fundamentally different mechanism than NAC — while NAC replenishes glutathione for detoxification, TUDCA prevents cholestasis (bile flow obstruction) which is the primary mechanism of oral steroid hepatotoxicity. C17-alpha-alkylated oral steroids cause dose-dependent intrahepatic cholestasis; TUDCA counteracts this by improving bile flow, protecting hepatocyte membranes, and preventing bile acid-induced apoptosis. For anyone running oral steroids, TUDCA alongside NAC provides the most comprehensive liver protection protocol available.
Non-benzodiazepine hypnotic for short-term insomnia treatment, often needed on certain compounds.
Boldenone Undecylenate (Equipoise/EQ) is a testosterone derivative with a double bond at the C1-2 position, giving it a lower androgenic profile and reduced estrogenic activity compared to testosterone. Originally developed for veterinary use, it is valued in bodybuilding for lean mass gains, enhanced vascularity, increased appetite, and elevated red blood cell production.
Long-acting nandrolone for steady mass gains, joint health, and recovery.
DHB (Dihydroboldenone, also known as 1-Testosterone) is the 5-alpha reduced metabolite of Boldenone. It is a potent anabolic compound with approximately double the anabolic potency of testosterone while having significantly lower androgenic activity. It does not aromatize to estrogen and produces lean, dry gains similar to Primobolan but at lower required doses.
Mild anabolic with endurance and vascularity benefits, known for appetite stimulation.
Masteron (Drostanolone) is a DHT-derivative anabolic steroid available as propionate (short ester) and enanthate (long ester). Originally developed for breast cancer treatment due to its anti-estrogenic properties, it is now primarily used in bodybuilding for its muscle-hardening, anti-estrogenic, and aesthetic-enhancing effects during cutting and contest prep phases.
Nandrolone is a 19-nortestosterone derivative available as Nandrolone Phenylpropionate (NPP, short ester) and Nandrolone Decanoate (Deca-Durabolin, long ester). It is one of the most popular anabolic steroids for mass building, prized for its strong anabolic effects, joint-supportive collagen synthesis properties, and relatively mild androgenic profile.
Fast-acting nandrolone for lean mass gains with joint support benefits.
Primobolan (Methenolone Enanthate) is a DHT-derivative anabolic steroid renowned for its exceptionally mild side effect profile and high safety margin. It does not aromatize, has low androgenic activity, and is considered one of the safest injectable AAS available. It is a favorite for lean tissue preservation during cutting phases and for those prioritizing health alongside performance.
Blend of four testosterone esters providing both fast-acting and sustained release.
Testosterone Cypionate is a long-acting esterified form of testosterone and the most commonly prescribed androgen in the United States. It serves as the foundational compound in nearly all anabolic steroid cycles due to its ability to maintain physiological testosterone levels and support anabolic processes.
Testosterone Enanthate is a long-acting esterified testosterone virtually interchangeable with Testosterone Cypionate. It is the most widely used testosterone ester globally and serves as the standard base compound for anabolic steroid cycles, providing reliable anabolic and androgenic effects.
Testosterone Propionate is a short-acting esterified testosterone with a fast onset and rapid clearance. It is favored for its ability to provide stable blood levels with frequent injections and for its faster clearance when transitioning to PCT, making it popular for shorter cycles and pre-contest preparation.
Trenbolone Acetate is a potent 19-nortestosterone derivative widely considered the most powerful anabolic steroid available. With an anabolic rating of 500 and androgenic rating of 500 (5x testosterone on both axes), it delivers dramatic physique and performance changes but carries a significantly harsher side effect profile than most other compounds.
Trenbolone Enanthate is the long-acting ester variant of trenbolone, offering the same extreme anabolic potency with a less frequent injection schedule. It is preferred by experienced users who have already assessed their tolerance with Trenbolone Acetate and want the convenience of 2x/week injections.
Anadrol (Oxymetholone) is the most potent oral anabolic steroid commercially available, with an anabolic rating of 320 and androgenic rating of 45. Originally developed for treating anemia and muscle-wasting diseases, it produces the most dramatic mass and strength gains of any oral AAS, but comes with a correspondingly severe side effect profile including significant hepatotoxicity and estrogenic effects despite not aromatizing.
Anavar (Oxandrolone) is a DHT-derived oral anabolic steroid and one of the mildest AAS available. It has an anabolic rating of 322-630 with an androgenic rating of only 24, making it highly anabolic with minimal androgenic side effects. It is widely used for cutting, lean gains, strength, and is one of the few AAS considered relatively safe for female users at low doses.
Clenbuterol hydrochloride is a selective beta-2 adrenergic agonist originally developed as a bronchodilator for the treatment of asthma. It is not a steroid, SARM, or hormone; it belongs to the sympathomimetic amine class. In the performance context, clenbuterol is primarily used as a thermogenic fat loss agent due to its ability to increase basal metabolic rate, stimulate lipolysis, and preserve lean muscle mass during caloric deficits. Clenbuterol also has mild anabolic properties in animal models (particularly in livestock, where it is used illicitly as a growth promoter), though these effects are much less pronounced in humans. It remains one of the most popular cutting compounds worldwide.
Dianabol (Methandrostenolone) is the most iconic oral anabolic steroid in bodybuilding history, developed by Dr. John Ziegler in the 1950s for US Olympic athletes. It is a testosterone derivative with added c17-alpha alkylation and a double bond at C1-2. Known for rapid and dramatic mass and strength gains, it remains one of the most popular bulking compounds despite significant estrogenic and hepatotoxic side effects.
Ultra-potent androgen used for extreme strength and aggression without mass gain.
Mild oral DHT derivative used to enhance free testosterone, libido, and muscle hardness.
Sildenafil is the original PDE5 inhibitor and remains the most widely recognized erectile dysfunction medication worldwide. For the PED community, it provides on-demand sexual performance support during cycles that impair function, as well as acute pre-workout vasodilation for enhanced muscle pumps. Its shorter duration of action (4-6 hours) compared to tadalafil makes it better suited for as-needed use rather than daily dosing. Sildenafil is also used at high doses (20mg TID as Revatio) for pulmonary arterial hypertension, demonstrating its potent vasodilatory properties.
Extremely potent oral with dramatic dry gains but significant liver toxicity.
T3 (Liothyronine, Cytomel) is the active form of thyroid hormone, approximately 3-5 times more potent than T4 (Levothyroxine) at the thyroid receptor. The thyroid gland primarily produces T4, which is converted to T3 in peripheral tissues by deiodinase enzymes. T3 is the hormone that directly drives metabolic rate, thermogenesis, protein synthesis, and energy expenditure. In the performance and body composition context, exogenous T3 is used to increase basal metabolic rate and accelerate fat loss during cutting phases. It is one of the most effective compounds for increasing daily caloric expenditure and is frequently stacked with anabolic compounds to prevent muscle loss.
T4 (Levothyroxine, Synthroid, Levoxyl) is the primary thyroid hormone produced by the thyroid gland. It serves as the "storage" or "prohormone" form of thyroid hormone, which is converted to the active form T3 (triiodothyronine) by deiodinase enzymes in peripheral tissues (liver, kidneys, brain, muscle). T4 accounts for approximately 80% of thyroid hormone output, while T3 accounts for approximately 20%. In the performance context, T4 is used as a milder alternative to T3 for metabolic enhancement and fat loss, as the body controls the conversion rate, providing a more gradual and physiological effect. It is also the standard treatment for hypothyroidism.
Tadalafil is a long-acting phosphodiesterase type 5 (PDE5) inhibitor primarily used for erectile dysfunction and benign prostatic hyperplasia. In the bodybuilding and PED community, it serves double duty: improving sexual function (which is commonly impaired during and after steroid cycles) and providing performance benefits through enhanced blood flow, vasodilation, and improved muscle pumps. Its 36-hour half-life makes it ideal for daily low-dose use, earning it the nickname "The Weekend Pill." Many AAS users run low-dose tadalafil throughout their cycles as a quality-of-life enhancement.
Turinabol (Oral Turinabol, OT, Tbol) is a derivative of Dianabol with an added 4-chloro modification that eliminates aromatization and reduces androgenic activity. Developed in East Germany in the 1960s for their state-sponsored doping program, it is known for producing slow, steady, lean gains without water retention. It is often described as a "milder Dianabol" with a more favorable side effect profile.
Winstrol (Stanozolol) is a DHT-derived anabolic steroid available in both oral and injectable (water-based) forms. Known for producing a hard, dry, and vascular physique, it is one of the most popular cutting and contest prep steroids. It gained mainstream notoriety through its association with Olympic sprinter Ben Johnson in 1988.
Anastrozole is a potent, selective, non-steroidal third-generation aromatase inhibitor (AI). It works by reversibly binding to the aromatase enzyme (CYP19A1), preventing the conversion of androgens (testosterone, androstenedione) to estrogens (estradiol, estrone). For AAS users, it is the most commonly used AI for controlling estrogen-related side effects during aromatizing steroid cycles — including water retention, bloating, high blood pressure, and gynecomastia. Proper estrogen management with anastrozole allows users to run higher doses of aromatizing compounds while minimizing estrogenic sides.
Non-steroidal aromatase inhibitor that reduces estrogen conversion during cycle.
Steroidal suicide aromatase inhibitor that permanently deactivates the aromatase enzyme.
Clomiphene citrate is a mixed-isomer SERM consisting of two stereoisomers: enclomiphene (trans-isomer, anti-estrogenic) and zuclomiphene (cis-isomer, weakly estrogenic). It has been the most widely used PCT compound alongside Nolvadex for decades. Clomid stimulates the HPTA by blocking estrogen negative feedback at the hypothalamus, driving increased GnRH, LH, and FSH secretion. It is particularly effective at raising FSH, which supports spermatogenesis — making it the preferred SERM when fertility preservation is a priority.
SERM that strongly stimulates gonadotropin release for testosterone recovery, though with more side effects than enclomiphene.
Enclomiphene is the isolated trans-isomer of clomiphene citrate — the active anti-estrogenic component responsible for HPTA stimulation. By removing the problematic zuclomiphene isomer (which causes mood disturbances, brain fog, and estrogenic accumulation), enclomiphene delivers the testosterone-boosting benefits of Clomid without the notorious side effects. It is rapidly becoming the preferred SERM for PCT and for men seeking an alternative to TRT that preserves fertility and natural hormone production.
Exemestane is a steroidal, irreversible (suicidal) aromatase inhibitor. Unlike anastrozole and letrozole which reversibly bind to aromatase, exemestane permanently destroys the aromatase enzyme molecules it binds to. The body must synthesize new aromatase enzymes to restore estrogen production. This suicidal mechanism eliminates the estrogen rebound effect that occurs when discontinuing reversible AIs. For AAS users, exemestane is often preferred over anastrozole because of its milder lipid impact, slight androgenic properties, and lack of rebound. It is the only AI that some experienced coaches consider acceptable in limited use during PCT.
Letrozole is the most potent aromatase inhibitor available, capable of reducing estradiol levels by 97-99% at standard clinical doses. It is a non-steroidal, reversible third-generation AI that binds aromatase with higher affinity than anastrozole. In the bodybuilding community, letrozole is considered the "nuclear option" for estrogen control — reserved for emergency situations like rapidly developing gynecomastia, severely elevated E2, or highly aromatizing cycles that do not respond to lower-potency AIs. Its extreme potency makes it easy to crash estrogen, so it requires careful dosing.
Tamoxifen citrate is a selective estrogen receptor modulator (SERM) and the gold standard PCT compound for restoring natural testosterone production after anabolic steroid cycles. It selectively blocks estrogen at breast tissue receptors while acting as a weak estrogen agonist in bone and liver. In PCT, it stimulates the hypothalamic-pituitary-gonadal axis by blocking estrogen negative feedback, increasing LH and FSH output to restart endogenous testosterone.
Classic SERM used for PCT and gynecomastia prevention by blocking estrogen at breast tissue.
Raloxifene (brand name Evista) is a second-generation selective estrogen receptor modulator (SERM) that is significantly more breast-tissue-selective than Nolvadex. While it is less commonly used for full PCT, it is considered the single most effective pharmaceutical option for reversing existing gynecomastia. Raloxifene has stronger antagonist activity at breast ER-alpha receptors than tamoxifen, with clinical studies showing gynecomastia reduction rates of 80-90% in pubertal cases. For steroid users, it is the go-to SERM when the primary concern is gyno reversal rather than HPTA restart.
BPC-157 (Body Protection Compound-157) is a synthetic pentadecapeptide (15 amino acids) derived from a protein found in human gastric juice. It has been extensively studied in animal models for its remarkable healing and protective properties across multiple organ systems. BPC-157 accelerates the healing of tendons, ligaments, muscles, bones, and the gastrointestinal tract. It is one of the most popular peptides in the performance and recovery community, used primarily for injury rehabilitation, joint healing, and gut health. While human clinical data is still limited, the breadth of animal research is extraordinary.
Cartalax (Ala-Glu-Asp, also known as A-E-D peptide) is a short-chain bioregulator peptide developed from the research of Professor Vladimir Khavinson at the St. Petersburg Institute of Bioregulation and Gerontology. It is part of the Khavinson peptide family of bioregulators, which are short peptides (2-4 amino acids) that interact with specific DNA sequences to regulate gene expression. Cartalax is classified as a cartilage and musculoskeletal bioregulator, targeting cartilage tissue, joint health, and the musculoskeletal system. It is used primarily for joint regeneration, cartilage preservation, and as part of anti-aging longevity protocols.
Growth hormone releasing peptide combo for natural GH pulse stimulation.
Neuropeptide that promotes deep delta-wave sleep and improves sleep architecture.
GHK-Cu (Glycyl-L-Histidyl-L-Lysine Copper) is a naturally occurring copper-binding tripeptide found in human plasma, saliva, and urine. Plasma levels of GHK-Cu decline significantly with age (from approximately 200 ng/mL at age 20 to 80 ng/mL by age 60), and this decline correlates with reduced regenerative capacity. GHK-Cu is one of the most extensively studied peptides for skin rejuvenation, wound healing, and anti-aging applications. It has the remarkable ability to reset gene expression patterns in aged tissue toward a healthier, younger profile. Beyond cosmetic applications, GHK-Cu promotes tissue remodeling, reduces inflammation, and supports overall connective tissue health.
Human Chorionic Gonadotropin (HCG) is a glycoprotein hormone produced naturally during pregnancy by trophoblast cells. In the performance and hormone optimization context, HCG is used primarily for two purposes: (1) maintaining testicular function and fertility during testosterone replacement therapy (TRT) or anabolic steroid cycles, and (2) as part of post-cycle therapy (PCT) to restart natural testosterone production. HCG mimics Luteinizing Hormone (LH) and directly stimulates the Leydig cells of the testes to produce testosterone and maintain testicular volume. It is an essential tool for men on TRT who wish to preserve fertility.
Human Growth Hormone (HGH, somatotropin) is a 191-amino acid peptide hormone produced by the anterior pituitary gland. It is the primary hormone regulating growth, body composition, cell repair, and metabolism. Synthetic recombinant HGH (rhGH) is bioidentical to endogenous growth hormone and is FDA-approved for growth hormone deficiency, Turner syndrome, and other conditions. In the performance and anti-aging context, exogenous HGH is used for fat loss, lean mass preservation, improved recovery, enhanced skin and hair quality, improved sleep, and overall anti-aging benefits. Natural HGH production declines approximately 14% per decade after age 30, driving interest in replacement.
Insulin-like Growth Factor 1 (IGF-1, Somatomedin C) is a 70-amino acid peptide hormone structurally similar to insulin. It is primarily produced by the liver in response to Growth Hormone (GH) stimulation and mediates many of GH's anabolic effects. IGF-1 is one of the most potent natural activators of the Akt/mTOR signaling pathway, driving cell growth, proliferation, and survival. In performance contexts, exogenous IGF-1 (specifically IGF-1 LR3, a modified long-acting variant) is used for its powerful anabolic and hyperplastic (new cell creation) properties. Unlike most anabolic compounds that only cause hypertrophy (enlargement of existing cells), IGF-1 can stimulate hyperplasia, creating entirely new muscle fibers.
KPV is a tripeptide (Lysine-Proline-Valine) derived from the C-terminal end of alpha-melanocyte-stimulating hormone (alpha-MSH). While alpha-MSH is known for its melanogenic (skin tanning) effects, KPV retains the potent anti-inflammatory properties of the parent hormone without causing skin darkening. KPV is a powerful anti-inflammatory peptide that works by inhibiting NF-kB signaling, the master regulator of inflammatory gene expression. It has shown remarkable efficacy in preclinical studies for inflammatory bowel disease, skin inflammation, and systemic inflammatory conditions. It is increasingly popular as a natural anti-inflammatory alternative.
Oral growth hormone secretagogue that elevates GH and IGF-1 levels around the clock.
Melanocortin receptor agonist used to treat sexual dysfunction and enhance libido.
Triple-agonist GLP-1/GIP/glucagon receptor peptide showing superior weight loss results.
Anxiolytic nootropic peptide that reduces anxiety and enhances cognitive function without sedation.
Semaglutide is a GLP-1 receptor agonist developed by Novo Nordisk. It is FDA-approved as Ozempic (for type 2 diabetes) and Wegovy (for chronic weight management). Semaglutide is a modified analog of human GLP-1 with 94% structural homology, engineered with a fatty acid chain that binds to albumin, extending its half-life to support once-weekly dosing. In the STEP clinical trial program, semaglutide 2.4 mg weekly produced average weight loss of approximately 15-17% of body weight. While surpassed by tirzepatide in head-to-head trials, semaglutide remains a highly effective and well-established weight loss peptide with an extensive safety record.
Nootropic peptide derived from ACTH that enhances memory, focus, and neuroprotection.
TB-500 is a synthetic peptide fragment of Thymosin Beta-4 (TB4), a naturally occurring 43-amino acid protein found in virtually all human and animal cells. TB-500 specifically replicates the active region (amino acids 17-23) of Thymosin Beta-4 responsible for actin binding and cell migration. Thymosin Beta-4 plays a critical role in tissue repair, wound healing, and anti-inflammatory processes throughout the body. TB-500 is widely used for injury recovery, particularly for slow-healing injuries like tendon damage, ligament sprains, and muscle tears. It has also gained popularity in veterinary medicine, especially equine sports medicine.
Tirzepatide is a first-in-class dual GIP/GLP-1 receptor agonist originally developed by Eli Lilly. It is FDA-approved as Mounjaro for type 2 diabetes and as Zepbound for chronic weight management. Tirzepatide simultaneously activates both the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, producing superior weight loss and glycemic control compared to GLP-1 receptor agonists alone. In the SURMOUNT clinical trials, tirzepatide produced average weight loss of 20-26% of body weight at the highest dose, making it the most effective non-surgical weight loss intervention ever studied.
PPAR-delta agonist (not a SARM) that dramatically improves endurance and fat oxidation.
LGD-4033 (Ligandrol) is a non-steroidal selective androgen receptor modulator originally developed by Ligand Pharmaceuticals and currently under clinical investigation by Viking Therapeutics. It is one of the most well-studied SARMs, with multiple Phase I and Phase II human clinical trials demonstrating its ability to increase lean body mass in a dose-dependent manner. LGD-4033 is a favorite among users seeking significant mass and strength gains with a more predictable and studied side effect profile. It is often considered the best "bulking SARM" due to its ability to produce substantial lean mass gains.
Ostarine (MK-2866, Enobosarm) is the most well-known and extensively studied SARM in existence. Developed by GTx Inc., it has undergone multiple Phase II and Phase III clinical trials for the prevention and treatment of muscle wasting in cancer patients. Ostarine is often recommended as the ideal first SARM cycle due to its mild side effect profile, moderate but reliable efficacy, and the wealth of human clinical data supporting its safety. It is highly effective for cutting, recomposition, and preserving muscle during caloric deficits.
RAD-140 (Testolone) is a non-steroidal selective androgen receptor modulator developed by Radius Health for the treatment of muscle wasting and breast cancer. It is widely regarded as one of the most potent SARMs available, delivering rapid strength and lean mass gains with a favorable anabolic-to-androgenic ratio. RAD-140 has approximately 90:1 anabolic-to-androgenic selectivity, meaning it strongly stimulates muscle and bone tissue while minimizing effects on the prostate and other androgen-sensitive organs. It is the SARM most often compared to low-dose testosterone for its efficacy.
ERR agonist (exercise mimetic) that enhances endurance and metabolic function.
Rev-ErbA agonist that enhances metabolic activity, endurance, and fat loss.
YK-11 is a synthetic steroidal SARM that acts as a potent myostatin inhibitor. Unlike traditional SARMs that work solely through androgen receptor modulation, YK-11 has a dual mechanism: it binds the androgen receptor while also inhibiting the myostatin pathway, which is the body's natural brake on muscle growth. This makes it one of the most powerful compounds in the SARM category for lean muscle gains. Structurally, it is derived from DHT and is sometimes classified as both a SARM and a myostatin inhibitor. Due to its steroidal backbone, YK-11 carries a somewhat higher risk profile compared to non-steroidal SARMs and should be approached with respect.