Andarine S4 Vs Ostarine MK-2866: Which is Better for Muscle Growth?

Andarine S4 and Ostarine MK-2866 both offer remarkable potential for bone and muscle growth, but their approaches differ significantly. Andarine S4 is better for cutting. On the other hand, Ostarine MK-2866 is a selective androgen receptor modulator cherished by bodybuilders and athletes for its strength and muscle-building benefits.

MK-2866 is more versatile and can be used for both bulking and cutting. In this blog post, we will discuss the details of these two powerful SARMs, exploring their mechanisms of action, benefits, and potential considerations.

Andarine S4 Vs Ostarine MK-2866: Quick Comparison

Here’s a brief comparison chart highlighting critical differences between Andarine S4 and Ostarine MK-2866:

FeaturesAndarine S4Ostarine MK-2866
Primary UseMuscle and bone development, fat lossMuscle preservation, fat loss, and healing injuries
Anabolic ActivityModerateMild
Androgenic ActivityMediumLow
Side EffectsVision problems, liver toxicity, joint pain, strokeHeart attack, liver damage, cardiovascular effects, sleeping issues, hair loss, acne
BenefitsIncreased muscle mass, fat loss, improved bone density, reduced water retentionMuscle preservation, enhanced performance, injury recovery, bone health
Dosage10mg per day10mg per day
CycleEight weeksSix weeks
Half-Life4-6 hours24 hours
ResultsFaster muscle gains, strength, and fat lossSlower muscle gains, muscle preservation, and fat loss
Gender SuitabilityBoth male and femaleBoth male and female
StackRAD 140 and MK 677Ostarine and MK 677

Read similar SARMs comparison here: RAD 140 VS LGD 4033

What is Andarine S4?

What is Andarine S4?

Andarine, marketed as MYO-S4 from Savage Line Labs, is a potent, selective androgen receptor modulator (SARM) gaining popularity in bodybuilding. This compound is designed to prevent muscle wastage and promote lean muscle mass development, resulting in a chiselled, challenging, and lean physique.

How Does Andarine S4 Work?

Andarine S4 works by binding to the androgen receptors in your body, specifically targeting those in your muscles and bones. This selective binding triggers a cascade of events that help you gain muscle mass and bone density. Unlike traditional steroids, MYO-S4 doesn’t affect other tissues like the prostate or hair follicles, making it a safer option for bodybuilders and athletes.

Andarine Cycle and Dosage

  • Dosage: Take 10mg per day
  • Cycle Length: 8-week cycle

Read our ultimate guide on MYO S4 from Savage Line Labs here: MYO S4 Review

Five Benefits of Andarine S4

There are five benefits of Andarine S4 are given below:

1. Muscle Growth

According to “Anabolic agents: recent strategies for their detection and protection from inadvertent doping by Hans Geyer” MYO-S4 can promote significant muscle growth by selectively binding to androgen receptors in muscle tissue. It can lead to increased muscle mass, strength, and endurance.

2. Fat Loss

S4 can help users achieve a leaner and more defined physique by increasing the body’s ability to burn fat. This effect mainly benefits individuals looking to reduce body fat while preserving muscle mass.

3. Improved Bone Density

According to “In vitro anti-carcinogenic effect of andarine as a selective androgen receptor modulator on MIA-PaCa-2 cells by decreased proliferation and cell-cycle arrest at G0/G1 phase by Aydin Boluk” This SARM was initially developed to address conditions like osteoporosis, and it remains a potential benefit of its use. By enhancing bone density, this compound can help strengthen bones and reduce the risk of fractures or injuries.

4. Enhanced Endurance

Users of MYO-S4 often experience an increase in endurance and stamina. It can be particularly advantageous for athletes and bodybuilders. It allows them to engage in longer, more intense training sessions, ultimately leading to better results.

5. Reduced Water Retention

S4 does not typically cause significant water retention or bloating. It can lead to a more vascular and defined appearance, which is desirable for many users, especially during cutting phases.

Five Side Effects of Andarine S4

Here we list five side effects of Andarine s4 below:

1. Vision Disturbances

According to “Side Effects of Andarine (S4) by Dylan Gemelli” 3% of Users may experience a yellowish tint in their vision, especially in low-light conditions. Some individuals have reported difficulty adjusting to changes in light, blurred vision, or issues with night vision.

2. Hormonal Imbalance

S4 can disrupt the body’s natural hormonal balance. It may suppress crude testosterone production, leading to hormonal imbalances. It can decrease some users’ libido, mood swings, and potential fertility issues.

3. Potential for Gynecomastia

According to “Characterization of In Vitro Synthesized Equine Metabolites of the Selective Androgen Receptor Modulators S24 and S4 by Oliver Krug” Gynecomastia, the development of male breast tissue, is a possible side effect of Andarine S4. This can occur because Andarine may affect the balance of hormones in the body, causing an increase in estrogen levels.

4. Changes in Lipid Profile

According to “S4 (Andarine): Results, Clinical Trials & Reviews by Derek” Andarine S4 can affect lipid metabolism, leading to alterations in cholesterol levels. Some users have reported decreased high-density lipoprotein (HDL) or “good” cholesterol levels, which can affect cardiovascular health.

5. Cardiovascular Effects

According to “Characterization of In Vitro Synthesized Equine Metabolites of the Selective Androgen Receptor Modulators S24 and S4 by Oliver Krug” Some users have reported mild cardiovascular effects, such as increased heart rate and blood pressure, while using Andarine S4.

What is Ostarine MK-2866?

What is Ostarine MK-2866?

Ostarine MK-2866, or MYO-STA, a popular choice among bodybuilders and athletes, is a selective androgen receptor modulator. It is enhancing muscle mass, strength, and overall performance. Beyond its fitness benefits, MYO-STA has garnered attention for potential medical applications, potentially aiding in treating conditions like osteoporosis and sarcopenia.

How Does Ostarine Work?

Ostarine, a powerful compound, enhances bodybuilding by targeting androgen receptors in muscle tissues. It stimulates muscle growth and improves strength without the side effects associated with traditional steroids.

MYO-STA promotes protein synthesis, making it a popular choice among fitness enthusiasts looking to sculpt lean, muscular physiques. Its selective action on muscle tissues and minimal impact on other organs.

Ostarine Cycle and Dosage

  • Dosage: Take 10mg per day
  • Cycle Length: 6-week cycle

Read our ultimate guide on MYO STA from Savage Line Labs here: MYO STA Review

Five Benefits of MK-2866

Here are five benefits of MK-2866:

1. Muscle Preservation and Growth

MYO-STA is known for its ability to help preserve and even promote muscle growth. It binds to androgen receptors in muscle tissues, increasing protein synthesis. It is particularly beneficial during calorie deficits or cutting phases when muscle loss is risky.

2. Enhanced Physical Performance

Users have reported improvements in physical performance when taking Ostarine. It includes increased endurance, strength, and stamina. Athletes and fitness enthusiasts sometimes use it to give them an edge in their training.

3. Fat Loss and Body Composition

This SARM can help users reduce body fat while preserving lean muscle mass. This effect benefits those aiming to achieve a more defined and leaner physique. It also helps improve overall body composition.

4. Injury Recovery and Bone Health:

MYO-STA may have a positive impact on bone density and joint health. It could be especially beneficial for recovering from injuries or dealing with conditions like osteoporosis.

5. Enhanced Metabolism:

While not a direct fat burner, Ostarine’s muscle-building effects can contribute to a higher resting metabolic rate. It means your body may burn more calories at rest, aiding in weight management.

Side Effects of Ostarine

Here we discuss the five side effects of Ostarine Mk-2866 are given below:

1. Hormonal Imbalance

Ostarine can suppress natural testosterone production, which may lead to hormonal imbalances. It can decrease libido, mood swings, and potential fertility issues, especially after prolonged or high doses.

2. Cardiovascular Effects

Some studies suggest that MYO-STA may have adverse effects on cholesterol levels. It can lower good cholesterol (HDL) levels and increase bad cholesterol (LDL), potentially impacting cardiovascular health.

3. Acne and Skin Issues

Ostarine may increase the risk of acne and skin problems due to its androgenic properties. Individuals with a history of acne may be more susceptible.

4. Insomnia and Sleep Disturbances

Ostarine may affect sleep patterns, leading to difficulty falling or staying asleep. Sleep disturbances can impact overall well-being.

5. Gastrointestinal Issues

MK-2866 may cause gastrointestinal discomfort in some individuals, including nausea, diarrhea, or stomach cramps.

Andarine vs Ostarine: Which One is the Best?

Andarine vs Ostarine: Which One is the Best?

Selecting the best between S4 and MK-2866 hinges on your fitness objectives. MYO-S4 boosts strength, while MYO-STA promotes lean muscle growth. Your choice should align with your specific goals.

Andarine vs Ostarine For Muscle & Strength

It ultimately boils down to your specific fitness goals and experience level. MYO-S4 is known for its potent effects, ideal for experienced users aiming to shed extra body fat. On the other hand, MYO-STA is a milder option, suitable for beginners or those seeking a more gradual approach to muscle development.

Andarine vs Ostarine: Which One Has the Least Side Effects?

Ostarine MK-2866 generally has the most negligible side effects. MYO-STA is a milder selective androgen receptor modulator (SARM) than MYO-S4. Both SARMs have undergone extensive research for their muscle-building and bone health benefits.

Ostarine stands out due to its reputation for minimal side effects, reducing the risk of issues like testosterone suppression and vision disturbances.

Learn more about SARMs side effects here: Side effects of SARMs and how to reduce them

Which One Costs More?

Both Andarine S4 and Ostarine MK-2866 are priced at $99.99, so there’s no difference in their costs. Whether you’re interested in MYO-S4 or MYO-STA, you won’t need to worry about the price. Both options come at an equal price, simplifying your choice based on your fitness goals and preferences.

Which SARMs Bring Faster Results?

The speed of results can vary from person to person. Andarine S4 is known for its quick action in promoting lean muscle mass and strength, often showing noticeable changes within 4 to 6 weeks. On the other hand, MYO-STA provides steady and sustainable gains, taking a bit longer for visible effects but with fewer side effects.

Can You Stack Both Andarine S4 & Ostarine Mk-2866 for Better Results?

Stacking SARMspc such as S4 and MK-2866 can yield impressive results in your fitness journey. MYO-STA is renowned for its muscle-preserving properties, making it an ideal choice during a cutting phase. However, combined with other SARMs like MYO-S4 in a bulking cycle or stack, it can surprisingly add lean muscle mass to your physique.


Is Ostarine Stronger than S4?

In a head-to-head comparison, MYO-STA is generally considered the stronger of the two compounds. Known for its potent muscle-building properties and effectiveness in fat loss, Mk- 2866 has become a favourite among bodybuilders and athletes.

Can You Stack Ostarine and Andarine?

Yes, you can stack Ostarine and Andarine together. For an effective SARMs stack, consider pairing MYO-S4 (50 mg) with MYO-STA (25 mg) daily over 8 to 12 weeks. This combination can help you achieve your fitness goals efficiently and with noticeable results.

Is Andarine S4 Good for Cutting?

Andarine S4 is excellent for cutting! This powerful SARM, known for its fat-shredding capabilities, has gained a stellar reputation among fitness enthusiasts. With its ability to target fat cells, preserve lean muscle, and enhance overall physique.

Are Ostarine and Andarine Hard on Your Liver?

Yes, Ostarine and Andarine, two popular SARMs, are a topic of concern when it comes to liver health. While renowned for their muscle-building properties, these compounds are not entirely benign regarding liver function. Mk-2866 and S4 may, in some cases, exert a mild strain on the liver. You can reduce these side effects bu using a post cycle therapy supplement like Savage PCT.

Where Can I Buy Andarine S4 Vs Ostarine MK-2866?

Where Can I Buy Andarine S4 Vs Ostarine MK-2866?

You can buy MYO-S4 and MYO-STA online. Ensure safety by choosing trusted sellers with third-party testing and quality guarantees. Look into reputable fitness supplement websites and even some physical shops for availability. If you’re searching for a reliable option, consider Your health and well-being should always come first when purchasing SARMs.

Final Thoughts on Andarine vs Ostarine

In the showdown between MYO-S4 and MYO-STA for muscle growth, your choice depends on your fitness goals and risk tolerance. MYO S4 excels in targeted muscle and bone strength enhancement, with potential side effects such as vision changes and Hormonal Imbalance.

Ostarine MK-2866 stands out with lower risks, promoting muscle gain, nitrogen retention, and metabolism while offering sustained energy. Your decision ultimately hinges on your specific objectives and comfort with potential side effects. These SARMs bring unique benefits, paving the way for a more robust and fitter you.


  • Natalia Leciejewska, Paweł A. Kołodziejski, Maciej Sassek, Leszek Nogowski, Emilian Małek, Ewa Pruszyńska-Oszmałek (April 15, 2022) Ostarine-Induced Myogenic Differentiation in C2C12, L6, and Rat Muscles
  • Fred A. M. G. van Geenen, Maurice C. R. Franssen, Ville Miikkulainen, Mikko Ritala, Han Zuilhof, Risto Kostiainen, Michel W. F. Nielen (January 7, 2019) TiO2 Photocatalyzed Oxidation of Drugs Studied by Laser Ablation Electrospray Ionization Mass Spectrometry
  • Pingxuan Shao, Yan Zhou, Dehua Yang, Ming-Wei Wang, Wei Lu, and Jiyu Jin (December 24, 2019) Synthesis of Aryl Propionamide Scaffold Containing a Pentafluorosulfanyl Moiety as SARMs
  • Kintz, Pascal; Ameline, Alice; Gheddar, Laurie; Raul, Jean-Sébastien (March 13, 2019) LGD-4033, S-4 and MK-2866 – Testing for SARMs in hair: About 2 doping cases
  • Adam T. Cawley, Corrine Smart, Candace Greer, Marcus Liu Lau, John Keledjian (October 12, 2015) Detection of the selective androgen receptor modulator andarine (S-4) in a routine equine blood doping control sample
  • Miklos, Vescan, Farczadi, Imre, Vari, Muntean (September 15, 2019) Development of an Analytical Methodology for the Qualitative and Quantitative Characterization of Capsules with Andarine, in Order to Use them to Investigate the Pharmacotoxicological Profile of the Substance
  • Rina Feder, Arie Dagan, Amram Mor (February 6, 2000) Structure-Activity Relationship Study of Antimicrobial Dermaseptin S4 Showing the Consequences of Peptide Oligomerization on Selective Cytotoxicity

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