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10 things you didn’t know about SARMs: The ultimate guide

The inside guide to SARMs (2020)

SARM is short for Selective Androgen Receptor Modulator. Steroidal SARMs have been around since the 1940’s and are based on testosterone. In the last 20 years a new group of compounds have been developed and studied: Non-steroidal SARMs. They are being researched as a possibly safer alternative to androgenic anabolic steroids (AAS). In this guide we explain how SARMs work, which different ones are available and why they have gained so much attention among bodybuilders and other sport 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. They are very effective in the treatment of several health conditions, including bone degeneration and muscle loss. Unfortunately, androgenic steroids come with unwanted side effects. As you are probably aware, a lot of 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 in binding to androgen receptors 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 a number of scientifically proven benefits, which have made them popular among bodybuilders and other sport enthousiasts.

Increase muscle mass

SARMs such as RAD-140, LGD-4033, YK-11 and S-23 have the ability to 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 are able to improve recovery. As a result, they can help in the healing of injuries.

SARMs side effects


SARMs have 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 suppresion. It is however still a known side effect.

Different types of SARMs

Not all compounds labeled as SARMs are actually 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 mode 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 actually isn’t a SARM. but a so-called Rev-ErbA agonist. It was first developed with the purpose of studying 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 known about this compound is based on anecdotal evidence and reports by users.


  • Increased endurance
  • Improved stamina
  • Stimulating fat burning


The average dose for SR9009 is 10 mg to 30 mg per day, with 20 mg being the most common dosage.


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 where given over an extended period of time. As a result, the mice showed an increased risk of tumors.  

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

GW 501516 dosage

Cardarine is most commonly used at a dosage of 20 mg per day.


MK-677 is a growth hormone secretagogue. Because it mimicks 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.  


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


The most common dosage for MK677 is 25 mg per day, although some prefer to not go over 10 mg per day.

MK-2866 (Ostarine)

MK-2866 is the most well-known and well-researched SARM. It is 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 of muscle than the placebo did in three months.

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


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

LGD-4033 (Ligandrol)

LGD-4033 is one of the most popular selective androgen receptor modulators. There is a fair amount of research on LGD 4033 showing remarkable results. It is more effective for increasing muscle mass then MK-2866 but has many of the same benefits as ostarine does.

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


RAD-140 is the most effective SARM for increasing muscle mass. Also known as testolone, it has a 90:1 anabolic to androgen ratio. The effects of RAD 140 are the closest to anabolic steroids of any non steroidal SARM.

Is RAD-140 Testolone the strongest SARM | HQSARMS
Is RAD140 the strongest SARM?


YK11 is the least researched compound in 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 actually 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