There is an increasing popularity surrounding SARMs, and their use among athletes, bodybuilders and recreational fitness enthusiasts. It appears to stem from the belief that SARMs can promote the increase of lean mass without many of the unwanted effects seen with anabolic steroid use and other performance enhancement drugs.
Despite this growing curiosity, SARMs have not been approved by the FDA for human consumption, outside of research.
Top SARMs for Lean Muscle Development
Ostarine (MK-2866): The Beginner-Friendly Option
Ostarine is one of the most studied SARMs, and considered one of the most used SARMs for muscle growth. Ostarine was originally developed by GTx, Inc. for muscle-wasting diseases and has been used by various fitness-minded individuals due to its relatively mild profile and consistent results.
The research has shown that Ostarine can help preserve and build lean muscle tissue while potentially aiding fat loss.(1) Users generally experience gradual muscle gain over cycles of 8-12 weeks, and most users have noticed a positive change with strength and endurance.
Ostarine is especially beneficial for those just starting or those who have taken time off from lifting and want to get back into lifting.
The standard dosage will fall around 10-25mg per day, with the majority of the users having success on the lower end. One of the more appealing aspects of Ostarine is its gentler nature. But with that said, there are always risks and side effects with even the mildest compounds.
Ligandrol (LGD-4033): The Muscle Builder
Ligandrol has developed a reputation as one of the most effective substances for the development of lean mass. As clinical studies indicate, LGD-4033 can lead to rapid, clinically significant increases in lean body mass.(2) For that reason, it has become a favorite among advanced users seeking significant and urgent muscle gains.
Users tend to report increases in strength and enhanced recovery between training sessions:
Inside Bodybuilding (2025)
One eight‑week personal trial recorded:
Bench press increased from 185×5 → 205×8 reps; overhead press 110×5 → 125×6; squat 230×5 → 255×8; deadlift 285×5 → 315×8.
The user reported “dramatic increases in strength and happiness,” and noted noticeably improved recovery between workouts during the cycle.
https://insidebodybuilding.com/lgd-4033-ligandrol/
In particular, this compound seems well-suited to help those who are looking to break through plateaus in their training or increase their rate of muscle growth.
Typical dosing ranges from 5-10mg daily, but many users have found that lower doses produce significant benefits while reducing the risk of potential side effects.
Because of ligandrol’s potency, even minor increases in dosage can have a powerful effect on results and side effect risk.
Andarine (S-4): The Cutting Specialist
Andarine holds a distinct place when it comes to SARMs as it possesses muscle-building and fat-loss effects, which is why it is common in cutting phases where users look to maintain lean muscle tissue and lower their body fat levels.
S-4 can help preserve lean muscle tissue during caloric restriction and can also potentially facilitate fat oxidation.(3) Users often report a harder, more defined appearance and maintained levels of strength during cutting phases.
The typical dosage of Andarine is typically within the range of 25-50mg daily, commonly split into several doses due to its relatively short half-life. Some users may report temporary side effects related to vision specifically when using doses in excess of 50mg which usually subside upon discontinuation.
Testolone (RAD-140): The Strength Enhancer
RAD-140 has drawn attention for its impressive muscle building effects and impressive strength gains. The research indicates that it may be one of the strongest SARMs on the market and is regularly utilized by advanced users looking for extreme results.
Studies show that Testolone can result in considerable increases in lean muscle mass and strength.(4) Most users have noted the ability to experience rapid strength gains and develop better gym intensity.
The compound seems to be particularly effective in helping those looking to unlock their muscle-building potential during bulking cycles.
Rad-140 is generally dosed at 10-20mg a day, but most users have commonly seen substantial results at the lower end. Because of its potency, RAD-140 can require a specific attention to dosing and cycle length to minimize the risk of side effects.
Best SARM Stack for Lean Muscle
Ostarine and Cardarine Combination
The Ostarine and Cardarine stack is one of the most common mixes used to build lean muscle. The intention of this stack is to combine the muscle-building effects of Ostarine with the fat-loss and endurance boosting effects of Cardarine.(5)
People using the Ostarine/Cardarine combination usually report gaining lean muscle while also getting leaner/improving body composition due to fat loss.
Reddit (r/SARMs, 2025)
A semi‑pro cyclist shared how stacking 10 mg Cardarine + 12.5 mg Ostarine for 10 weeks yielded major endurance upgrades and reduced fatigue, describing it as taking performance and recomposition to a “whole new level.”
https://www.reddit.com/r/sarmssourcetalk/comments/gt9yss/gw501516_mk2866_endurance_at_whole_new_level/
This combo seems most effective for users looking for a recomposition effect. This can be described as gaining muscle while losing fat while using this stack at the same time.
The Cardarine’s endurance benefits may be useful to help train harder, which can boost muscle-building efforts.
The most common dosing protocol is 10-20mg of Ostarine and 10-15mg Cardarine (daily). This stack is often referred to people who are new to using these types of compounds because it is a relatively mild stack, however, as with any supplementation proper care and monitoring should be used.
Ligandrol and Testolone Stack
The combination of LGD-4033 and RAD-140 puts forth a more potent muscle-building strategy. This stack combines two of the most potent muscle building SARMs and could lead to noticeable increases in lean mass for seasoned users.(6)
Users frequently report noticeable gains in muscle mass and strength with LGD-4033 and RAD-140 combination.
iSARMs Forum (2025)
Forum participants who ran combined LGD + RAD cycles describe visible results within 4–8 weeks:
“RAD‑140 provided immediate strength increases; LGD‑4033 gave more size and sustained fullness. Overall, 5–8 kg gains of clean muscle in 8 weeks, with noticeably higher output in compound movements.”
https://www.isarms.com/forums/threads/lgd-4033-and-rad-140-stacked.14761/
The synergistic effects of the compounds could increase muscle protein synthesis and improve training performance; however, this combination is more potent in the potential for side effects and should be monitored more closely.
A typical dosage would be 5-10mg of Ligandrol and 10-15 mg of Testolone combined daily. Due to the stack’s potency, it could be reserved for “only experienced” users who have successfully used SARMs individually before.
SARMs for Athletes: Performance and Ethical Issues
Studies have indicated that SARMs may improve athletic performance through effects on muscle mass and strength, as well as recovery from exertion. Each of these effects contributes to better performance in athletic endeavors that require strength or explosive performance. The selective action of SARMs may offer an advantage over traditional performance enhancing substances, particularly in terms of side effect abilities.
Currently, nearly all major sporting associations, including WADA, have prohibited SARMs for competitive athletics. Athletes who test positive for SARMs face severe consequences ranging from suspension to disqualification during competition.
The ethical considerations of performance-enhancing substances extend beyond simply breaking rules to fairness and competition in sport.
While SARMs may provide performance benefits in the short term, the long-term ramifications for cheating or violating the integrity of sport far outweigh the possible positive.
Legal and Safety
The legal standing of SARMs is highly variable by jurisdiction, and its status is changing as regulators evaluate these elements.
In the United States, the FDA has not given the green light for SARMs to be sold for human consumption outside the context of clinical trials. The FDA has sent warning letters to companies that sell SARMs marketed as dietary supplements, as these products cannot be legally marketed for human use.
The legal status is complicated and continues to evolve, with regulators continuing to evaluate their scheduling and control.
Other countries have taken a range of approaches to regulation of SARMs. A number of countries have endpoints in law that ban the sale and/or possession of SARMs, while others more nebulous laws regarding legality. Irrespective of a country’s laws regarding SARMs specifically, international travelers should research local laws closely; possession of these compounds may have legal implications in a certain jurisdiction.
SARMs are intended to be more selective in nature than traditional steroids, but they can still be associated with a number of potential side effects, such as hormonal suppression, stress on the liver, and alterations in cardiovascular function. The long-term impact of SARMs remains largely unknown, due to lack of research in healthy populations.
The personal decision to use SARMs should always be done with an awareness of potential dangers, importance of sourcing from a trustworthy supplier, and an understanding that unregulated markets mean that the quality and content (regarding potency, purity, or inadequate/false labeling of content) of SARMs will vary widely. Consequently, third party testing and certificates of analysis become extremely valuable in evaluating quality and legitimacy of products.
Maximizing Results While Minimizing Risks
The length of the cycle and the dosing protocol are important factors for both efficacy and safety. Most users do well with cycles that are 8-12 weeks long, followed by appropriate time off for hormonal recovery.
Start with lower doses and increase them slowly to assess tolerance to minimize side effects while determining what dose is ideal for a user’s particular situation.
Considerations for post-cycle therapy (PCT) become more critical for more suppressive compounds. While comparatively SARMs are much less suppressive than traditional steroids, there is still some level of hormonal suppression that could occur. If users wish to assess their testosterone levels, monitoring testosterone levels on SARMs (or other compounds) may also warrant prescribed PCT protocols.
Regular health monitoring during and after the SARM cycles is essential to understand how these compounds affect individual users. This type of blood work will assess liver function, lipid profile, and hormones, monitoring any potential issues before they develop into serious problems.
Building a Foundation for Success
To support muscle-building, adequate protein intake, an appropriate calorie balance, and proper nutrient timing are all also important. While SARMs may help improve the body’s efficiency in utilizing nutrients in the muscle building process, they are unable to overcome inadequate levels of nutrition.
Recovery practices that help facilitate muscle-building include: adequate sleep, adequate stress reduction, and adequate rest between training sessions.
References:
BodyConscious UK (2025) – “Ostarine MK‑2866: The Ultimate Research Compound for Lean Muscle Studies”Confirms that Ostarine’s selective binding to muscle and bone ARs yields: Enhanced protein synthesis, Preservation of lean muscle in caloric‑deficit settings, Improved bone density, Better recovery markers post training. https://bodyconsciousuk.com/blog/ostarine-mk2866-the-ultimate-research-compound-for-lean-muscle-studies/
- Frontiers in Endocrinology (2025):
Reviews clinical trial data showing LGD-4033 produces consistent increases in lean mass as measured by DXA and muscle strength tests. “Participants gained significant lean body mass, typically 1–2 kg over three to eight weeks, with mild or transient side effects.”
https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2025.1634799/full - Savage Research Labs (2024):
“Andarine (S4) is known for its ability to increase strength, improve muscle density, and support fat loss. It’s particularly effective for those looking to cut down while preserving muscle, as it provides mild anabolic effects without excessive muscle bulk. Andarine binds to androgen receptors in muscle and bone, increasing muscle density while promoting fat loss. It has a unique muscle-hardening effect, making it a favorite for bodybuilders in the cutting phase.”
https://savageresearchlabs.com/sarms-for-fat-loss-shed-body-fat-and-preserve-muscle-with-science-backed-options/ - Scientific Review (2025):
“RAD-140’s supplementation with other SARMs … was determined to increase muscle mass as well as strength in large animal and in vitro models.”
https://pmc.ncbi.nlm.nih.gov/articles/PMC12311314/ - APH Science (2025):
“Stacks such as Ostarine plus Cardarine are widely used for recomposition goals. Ostarine supports muscle growth and retention during calorie restriction, while Cardarine increases stamina and directly accelerates fat oxidation. The combination is reported to be highly synergistic for athletes looking to spare muscle and lose fat simultaneously”
https://aphscience.com/blogs/news/how-can-cardarine-and-s4-burn-fat-while-retaining-muscle - TMSafric (2025):
Reports that the RAD‑140 + LGD‑4033 stack produces significant gains in muscle size, strength, and endurance. RAD‑140 triggers faster hypertrophy, while LGD‑4033 enhances recovery and reduces muscle soreness through sustained AR activation. Together, they support higher mitochondrial performance and oxygen efficiency, improving both muscle density and output.
https://tmsafric.com/13190208/discoveries-in-the-quot-rad-140-and-lgd-4033-stack-quot/
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