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SARM guide: A complete overview of SARMs

The inside guide to SARMs (2020)

What are SARMs?

SARMs, short for Selective Androgen Receptor Modulators, are a group of compounds being researched as a possibly safer alternative to anabolic steroids. Because these compounds have a more selective method of action and only target the androgen receptors in certain types of tissue, they could replace androgenic steroids as a treatment for various medical conditions.

Steroidal SARMs, based on Testosterone, have been around since the 1940s. During the last 20 years, a new group of compounds has been developed and studied: Non-steroidal SARMs.

In this guide, we explain how they work, which are available, and why they have gained so much popularity among bodybuilders and other sports fanatics.

“SARMs are promising drugs to treat the serious problem of muscle wasting that occurs in patients with a variety of disorders, including cancer cachexia and sarcopenia in the elderly. The findings reported today demonstrate that LGD-4033 has the potential to be an important new option for these patients by offering improved safety compared to currently available drugs based on its tissue-selective effect. As muscle wasting and osteoporosis are common co-morbidities in the elderly, LGD-4033 may be particularly beneficial to frail, elderly patients by improving their mobility and quality-of-life, and reducing the risk of fall-related bone fractures.”

Martin D. Meglasson, Ph.D., Ligand’s Vice President of Discovery Research

SARMs as an alternative to steroids

Androgenic anabolic steroids (AAS) have a long history in the medical field because they are highly effective in the treatment of several health conditions, including bone degeneration and muscle loss. Unfortunately, androgenic steroids have many unwanted side effects. As you probably know, many people experience acne and hair loss caused by the use of anabolic steroids.

Science has therefore been searching for alternatives that are less prone to cause side effects. And this is where non-steroidal SARMs come into view.

There are a lot of different SARMs in varying stages of research. There have been clinical trials for the treatment of osteoporosis.


SARMs work by targeting the androgen receptors (AR) in a tissue-selective way. Androgen receptors exist throughout the body, but they have different functions depending on the kind of tissue. Androgenic anabolic steroids (AAS) generally affect all androgen receptors, resulting in certain benefits but also unwanted side effects.

SARMs are more selective, only targetting the androgen receptors in specific kinds of tissue, minimizing side effects while still providing the benefits of AAS.

The androgen receptors in skeletal muscles are responsible for the anabolic effects. They increase muscle growth, prevent bone loss, and play an important role in fat burning.

SARMs benefits

SARMs have several scientifically proven benefits, which have made them popular among bodybuilders and other sports enthusiasts.

Increase muscle mass

SARMs such as RAD-140, LGD-4033, YK-11, and S-23 can increase muscle mass. While the anabolic effects are usually not as strong as those of androgenic steroids, they are still quite effective in building lean muscle mass.

Improve bone density

Fractures and broken bones are often a result of decreased bone density. Another common effect of SARMs is the ability to prevent bone loss. Because these substances trigger the androgen receptors in skeletal muscle tissue, they can improve bone density.

Improve recovery and healing

Some SARMs can improve recovery. As a result, they can help in the healing of injuries.

What are the side effects of SARMs?


SARMs have been shown to suppress luteinizing hormone (LH) and follicle-stimulating hormone (FSH) through the hypothalamus-pituitary-testis axis, thus decreasing testosterone in a dose-dependent manner.

When compared to androgenic anabolic steroids, the suppression of natural testosterone levels is fairly limited. As a result of the more selective binding to androgen receptors, SARMs do not have the same negative side effects associated with testosterone suppression. It is however still a known side effect.

Different types of SARMs

Not all compounds labeled as SARMs are selective androgen receptor modulators. For instance, Cardarine (GW-501516), Stenabolic (SR-9009), and Ibutamoren (MK-677) do not bind to the androgen receptors. They have a different modes of action.

However, we will still discuss these substances in this guide because they are often used for performance enhancement, much in the same way as SARMs. SARMs and similar compounds are used as an alternative to anabolic steroids.


SR 9009 is the first example of a research drug that isn’t a SARM. but a so-called Rev-Erba agonist. It was first developed to study the circadian rhythm. Initial lab studies showed that SR9009 is capable of increasing exercise capacity.

SR 9009 has not been approved for human consumption by the FDA. Therefore most of what we know about this compound is based on anecdotal evidence and reports by users.

Stenabolic benefits

  • Increased endurance
  • Improved stamina
  • Stimulating fat burning

For more info: A review of Stenabolic: Dosages, results and side effects

Cardarine (GW-501516)

GW-501516, also known as Cardarine and Endurobol, is a compound that isn’t a SARM either. It is a so-called PPARδ receptor agonist that has initially been researched as a possible treatment for metabolic and cardiovascular diseases. Medical research was stopped during phase 2, because of the results of a study on mice. In this study, huge dosages were given over an extended period. As a result, the mice showed an increased risk of tumors.  

Cardarine has gained popularity because of several reported benefits. It is used among athletes and bodybuilders because it improves stamina and cardiovascular endurance and for its fat-burning capabilities.

Cardarine benefits

  • Increased endurance
  • Stimulates fat burning
  • Enhanced stamina

For more info: The complete guide to Ostarine

Ibutamoren (MK-677)

MK-677, also known as Ibutamoren, is not a SARM but a growth hormone secretagogue. Because it mimics the effects of Ghrelin, Ibutamoren increases the release of growth hormone (GH) and insulin-like growth factor (IGF-1). While other substances that increase HGH and IGF-1 levels are generally peptides, MK-677 is the only orally active compound capable of this effect.  

Ibutamoren benefits

  • Decreased recovery time
  • Improving sleep quality 
  • Reduced body fat
  • Increased muscle mass

For more indepth information about Ibutamoren, read our article: The full MK-677 guide

Ostarine (MK-2866)

MK-2866 is the most well-known and well-researched SARM. It is also considered pretty mild and safe. It prevents muscle wasting, improves bone density, and improves recovery.

The scientific study put users on 3 mg of Ostarine per day, and they ended up gaining 3 pounds more muscle than the placebo did in three months.

To put this in perspective, Ostarine is safe in dosages up to 50 mg per day. That’s more than 15x what the study gave their users.


Ostarine benefits

Increases lean muscle mass

A study performed on 159 cancer patients who took either 1 or 3mgs of Ostarine per day for 113 days showed that both groups exhibited lean muscle growth. They gained around two to three pounds of lean muscle mass. 

Increases bone and muscle strength

Although no human studies confirm these findings, we do have animal studies that showed Ostarine has very good effects on our bone and muscle strength. This is not only good news for those suffering from osteoporosis, but also for bodybuilders who seek more muscle strength and sturdiness. Moreover, this benefit will help you keep your existing muscle during a cut.

Increases fat loss

Ostarine can improve fat-free mass by decreasing the amount of fat in our bodies. This has been confirmed by the following study.

For more information, please read: What is MK-2866 or Ostarine?

Ligandrol (LGD-4033)

LGD-4033, better known as Ligandrol, is one of the most popular selective androgen receptor modulators.

Together with Ostarine, it is one of the few SARMs that have gone through several clinical trials, with very promising results. LGD 4033 is the strongest SARM when measured on an mg for mg basis.

The human studies on Ligandrol have all confirmed that this SARM is safe and well-tolerated, even in dosages up to 22mg.

Ligandrol Benefits

Increases lean muscle mass

study on 76 healthy males between the ages of 21 to 50 revealed that Ligandrol could increase lean muscle mass by up to three pounds on a 1mg dosage in just 21 days. The increase was dose-dependent, meaning that a higher dosage should technically net more gains.

Increases strength

Although not as strong as RAD 140, Ligandrol still packs a punch when it comes to increasing strength in bodybuilders. 

Faster recovery times

Once again, this is all anecdotal evidence from bodybuilders that have taken Ligandrol. They claim that this SARM has helped them lower their recovery times by up to 50%, which vastly improved their efficiency when it came to lifting weights.

For more information please read: What you need to know about LGD-4033

Testolone (RAD-140)

RAD 140, also known as Testolone, is the most effective SARM for increasing lean, dry, muscle mass. RAD 140 also provides significant strength gains.

Compared to Testosterone, RAD 140 exhibits an androgenic to anabolic ratio of 90:1, which is considered very high, even for SARMs.

Unlike Ligandrol, RAD 140 is a partial agonist of the androgen receptor, which means that it doesn’t cause as much suppression as the former. Finally, RAD 140 is very potent at low dosages, harboring many benefits in a short period.


YK11 is the least researched compound on this list. YK 11 is different than other SARMs because it is the only one that has a steroidal molecular structure. This has caused some debate about whether YK-11 is a SARM or a synthetic androgenic anabolic steroid. On top of that, it has another unique property in that it’s acting as a myostatin inhibitor.

For more information please read: YK-11 is more than just a SARM

Half-life of SARMs

The halflife of a drug is the amount of time it takes for half of it to be eliminated from the body.

SARMActive Half-life
Testolone RAD-14020 to 24 hours
Cardarine GW-50151616 to 24 hours
Ligandrol LGD-403324 to 36 hours
Ostarine MK-286624 hours
S-23 12 hours
YK-11 6 to 8 hours
Ibutamoren MK-67724 hours
Stenabolic SR-90094 hours
Are SARMs safe?

SARMs are developed as a possible safer alternative to anabolic steroids. Because they work more selectively than their steroid counterparts, they don’t come with the same unwanted side effects.

Do SARMs require a PCT?

While SARMs are less suppressive than anabolic steroids, they still lower your natural testosterone production. For some SARMs including RAD-140, YK-11 and S-23, a PCT is recommended to restore natural hormone levels after a cycle. K-2866, GW-501516, SR-9009 and MK-677