Some of the most common dosages are listed below. However, note that the dosages you see are variable depending on the user’s tolerance.
Ligandrol (LGD-4033) Dose & Cycle: User experience has shown benefits at dosage ranges of 3mg-10mg with a time span of 24-36 hours in-between each administration. Improvements have been noticeable in research subjects in as little as 2 weeks and continues upwards until 5 months in (20 weeks). There is a noticeable increase in tolerance around 3 months of consistent use, at which point, the benefits begin to progressively decrease.
Ostarine (MK-2866) Dose & Cycle: Ostarine has an effective dosage range of 25-50mg every 24-36 hours. There has been no significant evidence showing that increasing dosage beyond 50mg produces better results. Multiple studies have shown that Ostarine demonstrates safety and effectiveness up to 6 months (24 weeks) of consistent use.
Andarine (S4) Dose & Cycle: S4 produces the best results at a dosage range of 25-50mg three times per day. Due to these higher doses, there is greater chance of side effects. Adarine has proven to be effective up to 3 months of use.
Testalone (RAD140) Dose & Cycle: Testalone is considered to have similar effectiveness and potency to that of LGD-4033 so it’s dosages are based largely off of that assumption (dosage studies are still being produced). Common dosages for people experience skeletal muscle hypertrophy are in the range of 20-30mg per 24-36 hour time period. Recent studies have been revealing safe use of Testalone for up to 24 weeks.
YK-11 Dose & Cycle: The studies on YK-11 doses are quite limited at this moment so we are forced to base most of these numbers on user experience. Most users in SARM related forums mention they experience the best results using anywhere between 5-12mg two times per day. The reason for take YK-11 twice per day is because of it’s potentially short half-life. As of now, there is not much out there in terms of how long users can safely cycle on Yk-11; it is best to stray on the side of caution.
Anabolicum (LGD-4033) Dose & Cycle: This SARM is considered to be extremely potent so users can get away with much smaller doses than usual. Most users have experienced great benefits at 10mg once in a 24-38 hour time span. Most cycles on Anabolicum last the standard 8 week protocol.
Cardarine (GW 501516) Dose & Cycle: A sufficient dose for Cardarine is between 10-20mg per day. It is suggested that you begin with a 10mg dose and scale this higher as needed. Keep in mind that 10mg is more so for endurance purposes while higher doses will mostly benefit fat loss. Cardarine is generally cycled on for 12-14 weeks with a 4-6 week break in between cycles. GW 501516 is meant for long-term use so there is no evidence that users need to cycle off it. However, since these are research chemicals, it is suggested to always air on the side of caution.
Nutrobal (MK-677) Dose & Cycle: User experience has shown that between 10-25mg once per day seems to be the bread and butter dosage range for Nutrobal. Many users cycle this chemical on a normal SARM cycle of 8-14 weeks on and 4-6 weeks off.
Stenabolic (SR9009) Dose & Cycle: The average Stenabolic dosage is 20-30mg per day. However, the half life of this chemical is extremely short (2-4 hours) so you’ll want to space your dosing throughout the day in even intervals. Once again, treat Stenabolic with the same cycle period commonly associated with SARMs (8-14 weeks on 4-6 weeks off).
Sarm Science on S23
S23 is a selective androgen receptor modulator (SARM) currently under development for potential use as a male hormonal contraceptive.
It is still in the preclinical stage of development, meaning it has only been tested on animals, not humans.
S23 exhibits a high affinity for the androgen receptor with tissue selective anabolic effects in muscle in bone, with relatively less stimulation of the prostate, seminal vesicles, and other androgen affected tissues.
S23 was created by modifying the structure of an older and less efficacious SARM called C-6 by changing the para-nitro group of C-6 to a cyano group [R].
Pharmacokinetic studies showed that C-6 is 76% orally bioavailable, and by swapping the para-nitro group for a cyano group S23 is able to achieve 96% oral bioavailability [R].
The closer a SARM is to 100% the closer it is to complete absorption after oral dosing.
This means that S23 can be administered orally, as opposed to requiring injections to achieve maximal blood serum concentration levels, which is obviously advantageous when it comes to ease of use and adoption.
The preclinical data revealed that S23 is the most suppressive SARM in development and resulted in infertility in all rats treated.
Expectedly, this raised interest in its potential clinical applications as a form of male birth control.
The most obvious drawback of the long-term utilization of SARMs in a hormone replacement context, or as a male hormonal contraceptive in the case of S23, is their lack of aromatization into Estrogen.
S23 is no different as it does not aromatize into Estrogen in the body, and would require exogenous Estrogen administration in order to maintain normal sexual behavior, among a myriad of other physiological functions that are facilitated by healthy endogenous Estrogen levels.
Contrary to popular belief, this also includes muscle building potential, as a lack of adequate Estrogen in men will not only hinder bone health, it will also severely inhibit the accrual of lean muscle mass.
Its potential efficacy in a hormone replacement therapy context is outlined in the preclinical animal data, but the scientists also acknowledge the limitations of S23 monotherapy when considering it in this context.
S23 has become increasingly popular in the recreational bodybuilding community for its potent muscle building and body recomposition effects.
Recreational users are quick to label S23 as a more potent alternative to S4 (Andarine)without the night vision side effect.
S23 has also shown to decrease prostate size in studies, which is the opposite of a very common negative side effect of anabolic steroids (enlargement of the prostate).
This data is commonly misinterpreted though, as all SARMs will cause prostate hypertrophy in a dose dependent manner, and this is specifically referred to in the study.
S23 in particular was shown to maintain the anabolic activity in muscle tissue equivalent to therapeutic levels of Testosterone at 0.1 mg per day in rats, while only stimulating prostate size up to 30% of an intact control rat (a healthy non-castrated rat with normal Testosterone/DHT levels) [R].
However, at dosages of 1 mg per day S23 maintained the prostate and seminal vesicles at weights equal to or greater than that observed in the intact rats.
Anecdotally, S23 is one of the most side effect ridden SARMs of all due to its high level of androgenic activity relative to other SARMs.
S23 has a very high binding affinity for the androgen receptor (AR) with a Ki of ∼1.7 nM [R].
The structural modification of C-6 didn't just increase S23's oral bioavailability, it also increased its AR binding affinity two times higher than that of C-6, which has a Ki of ∼4.9 nM.
To put this in perspective, RAD140 demonstrated excellent affinity for the androgen receptor with a Ki of 7 nM [R].
S23 has a binding affinity over four times higher than RAD140, which was already considered impressive.
The binding affinity of Testosterone and DHT remains unclear as each study seems to render significantly different values.
In the RAD140 study the affinity for the androgen receptor for Testosterone was 29 nM, and 10 nM for DHT.
In the study conducted on S23, DHT was stated to have a Ki of 0.45 nM.
The only SARM in development that is reported to have a formidable binding affinity to S23 is LGD-4033, which has a Ki of ∼1 nM [R].
Mechanism Of Action
S23 has a very high level of bioavailability which means it can be dosed orally without the need for injections or other inconvenient methods of administration.
S23 is not methylated and does not require methylation to achieve 96% oral bioavailability, making it superior to traditional oral anabolic androgenic steroids in the context of liver toxicity.
Oral steroids that feature a methyl or ethyl group at the C17α position are intentionally liver toxic so they are orally bioavailable and won't be destroyed by the liver.
S23 and other SARMs appear to circumvent this issue.
After administration, S23 binds to the androgen receptor with a very high affinity, and actively competes with Testosterone and DHT for AR activation.
Because of its high binding affinity, it is very effective at outcompeting Testosterone and DHT for receptor sites in muscle tissue and bone.
After binding to the androgen receptor, S23 increases bone mineral density, lean mass, and reduces fat mass in a dose-dependent manner [R].
SARMs, like S23, stimulate androgen receptors in a selective way, whereby they induce a significantly greater amount of anabolic activity in the body relative to androgenic activity [R].
The high level of tissue selectivity and competitive binding affinity at the AR may potentially avert some of the risks and side effects that can occur when endogenous Testosterone is 5α-reduced into the more androgenic metabolite DHT.
Some of these negative effects include but are not limited to benign prostate hyperplasia, prostate carcinoma, acne breakouts, and expedited male pattern baldness.
The relative lack of androgenicity makes S23 a strong candidate for potential clinical applications for both men and women.
However, while its tissue selectivity is superior to most FDA approved anabolic steroids, S23 has shown to be a full agonist in androgenic and anabolic tissues [R].
This makes it unique from other SARMs in development that are more prostate-sparing and selective for muscle tissue and bone, and most likely disqualifies its viability as a treatment for anything other than a male hormonal contraceptive.
Increases Muscle Mass And Bone Mineral Density
During the preclinical profiling of S23, it increased lean mass and bone mineral density [R].
This was not in a dose-dependent manner however, which implies that S23 has a point of diminishing returns in an anabolic context, and dosages higher than that point would just results in higher levels of androgenic activity and HPTA suppression.
In another study comparing the efficacy of S23 to Testosterone, S23 attenuated muscle and bone tissue catabolism induced by the glucocorticoid dexamethasone and castration more effectively than Testosterone, with less androgenic activity [R].
The intention of the study was to establish how effective a SARM like S23 would be at preventing musculoskeletal degeneration in two scenarios that are common among men and women.
One being musculoskeletal degeneration among hypogonadal men, and the other being musculoskeletal degeneration induced by prolonged use of glucocorticoids.
Skeletal muscle wasting currently has no therapy, and the current treatments have all been riddled with severe limitations.
Namely the androgenicity of anabolic steroids inducing virilization in women and androgen derived health ramifications in both men and women, as well as severe insulin resistance among those treated with growth hormone.
Growth hormone still has yet to prove it has any anabolic effect on muscle tissue whatsoever, and it is illogically prescribed in absurd quantities to AIDS patients.
Anecdotally, S23 is reported to be one of the most potent muscle builders among all of the SARMs currently in development.
S23 decreases fat mass in a dose-dependent manner [R].
While the preclinical profiling revealed dose-dependent fat loss, I believe this is an indirect effect, rather than the direct mobilization of stored fat.
In general, anabolic agents do not burn fat.
As a human accrues more muscle mass, their basal metabolic rate will increase in parallel.
This is guaranteed, therefore anything that can increase lean muscle mass will also indirectly impact total daily energy expenditure.
Via increasing muscle mass S23 will also increase the body's metabolic rate (because it has more muscle tissue burning through more calories), which will indirectly result in increased fat loss in a dose-dependent manner in parallel to muscle mass accrual.
It is very likely that S23 can indirectly increase fat loss, and that the amount of fat loss is entirely dependent on how much lean muscle gain is facilitated by the S23.