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ACP-105: Benefits, Side Effects, Proper Use & Protocols

ACP 105

What is ACP-105?

ACP-105 is a fairly new SARM that’s been gaining popularity as a potentially safer and more powerful alternative than Andarine (S4) and Ostarine (MK2866).

It was developed by Acadia Pharmaceuticals for the treatment of muscle-wasting conditions and osteoporosis but, unfortunately, it has not undergone human clinical trials as of writing. So we only have pre-clinical and anecdotal data on its properties.

Those who have used it compare it to Andarine in terms of benefits and Ostarine in terms of side effects. This makes it the potential “best” SARM for cutting, if more anecdotal and academic data confirms it.

In this article, I’ll go into detail about ACP-105, its benefits and side effects, and how to properly use it, all based on the latest academic data, as well as the analysis of hundreds of anecdotal reports and experiences online.

Empirical Data & Observations

As a professional in this space, I am not only constantly reading and analyzing such reports, but also conducting my own experiments in conditions deemed as controlled as possible by academic standards, with all biomarkers monitored.

This is a summary of anecdotal reports, collected from various sources, including Reddit and forums, that detail the effectiveness and potential drawbacks of ACP-105.


Empirical data indicates that ACP has significantly greater potency than Ostarine and S4 on a milligram per milligram basis. Furthermore, ACP induces less suppression than Ostarine and S4, with doses as low as 15mg/day of ACP being reported to be as effective as 50-60mg/day of S4.

ACP has also been reported to have the least side effects among all SARMs. Reports indicate that ACP may negatively impact lipids, but not liver enzymes, which is common in Ostarine use. Additionally, ACP does not have vision side effects like S4.

Interesting Properties

Some users also report cognitive/nootropic benefits, including improved memory and increased mental clarity and well-being.

However, there are potential drawbacks associated with ACP-105. It is relatively expensive, and it has a short half-life, requiring at least three doses per day to maintain stable levels. It’s also hard to source, though some of the biggest vendors recently started selling it.

Due to its short half-life, there is an interesting proposition circulating in forums that suggests ACP can be used as a pre-workout supplement, either on its own or in combination with other compounds.

When used as a solo run, ACP has been claimed to eliminate suppression, as the HPTA is mostly active at night. Users may also benefit from increased androgen receptor (AR) stimulation during workouts and the post-workout anabolic window.

It is also interesting to note that ACP is the smallest molecule among all SARMs, with a molecular mass of 290 compared to 338 for LGD 4033 and 393 for RAD 140, among others. This may contribute to its high bioavailability and present unique possibilities for sublingual, transdermal, and other applications.


Accurately determining exactly how effective ACP-105 is at any of these is difficult because we lack clinical data. Those who have used it compare the benefits to high dose Andarine (S4) but without the vision impairment. 

Muscle Building [A]

ACP-105 has been mostly used as a cutting agent and is shown to retain muscle mass on a caloric deficit, similar to Andarine. Some users have reported that they even gained muscle while cutting, though that is definitely not possible with aggressive dieting and large deficits.

Increased Strength & Performance [A]

ACP-105 increases strength, stamina, and overall performance. However, we cannot pin down exactly how effective it is in comparison to other SARMs. Considering that it’s categorized as a mild SARM, one would assume that the extent of this increase in performance is comparable to Ostarine and Andarine.

Many users have reported the strength gains from ACP to be very decent, also taking into account they ran it for a cutting cycle.

Fat Loss [A]

ACP-105 will not help you lose more fat, but it will retain and possibly increase muscle on a caloric deficit.

Bones and Joints [A]

ACP-105 will increase the strength and density of your bones. This is a common property all SARMs share. However, there is no data supporting joint healing properties like Ostarine. But it also doesn’t cause dry joints, which is common with other dry compounds.

Recovery [A]

ACP-105 will speed up your recovery. You’ll be less sore, less fatigued, and less tired after workouts. 

Cosmetic [A]

On ACP-105 you can expect to achieve a very dry, hard, and vascular look. In terms of the cosmetic benefits, it’s very comparable to Andarine. Perfect for photoshoots or competition prep.

P.S. Make sure the ACP-105 you’re getting is legit. These are my recommended sources for the highest-quality ACP-105 available:

  • US – Discounted Prices: POP10 (Highest Possible)
  • EU – Discounted Prices: POP20 (Highest Possible)

Side Effects

Accurately determining the extent of ACP’s side effects is difficult. Those who have used it compare the side effects to that of Ostarine (MK-2866), with most being linent towards ACP-105 as the safer SARM. 

In my opinion, this might not be the case, as Ostarine is wildly better researched as opposed to ACP, with many clinical trials to its name. Nevertheless, these are the side effects observed in the available empirical data thus far.

Testosterone Suppression [A]

The vast majority of ACP-105 users will not experience any of these symptoms. Those who do, experience no more than one or two, and for a short timeframe towards the end of a cycle and for a week or two after it.

The vast majority of ACP 105 users will not experience any of these symptoms. Those who do, typically experience no more than one or two, and for a very short timeframe – towards the end of a cycle and for a week or two after it.

SHBG Suppression [A]

ACP-105 will decrease SHBG (sex hormone-binding globulin).

This will lead to an initial increase in free testosterone during the first weeks of the cycle until the suppression of total testosterone offsets it.

This increase in free testosterone will result in an increase in libido, motivation, and overall well-being.

Increased Cholesterol - Dyslipidemia [A]

ACP-105 will disrupt the ratio between good cholesterol (HDL) and bad cholesterol (LDL), lowering the former and increasing the latter.

I’ve seen plenty of bloodwork proving this to be the case. Unfortunately, this is a side effect that’s common with all SARMs, and while ACP looks promising as far as low side effects go, it still causes it.

Liver Toxicity [A]

Though there isn’t any scientific evidence suggesting that ACP-105 is liver toxic, and there is also no anecdotal evidence showing elevated liver enzymes after a cycle. You can still assume that it might be liver-toxic despite this.

Other Side Effects [A]

Considering how limited info on ACP-105 is, there may be side effects that we don’t know of yet because they haven’t been reported.

The following side effects are generally rare side effects that can happen to anyone who uses drugs that disrupt their hormonal balance, including all SARMs:


Gynecomastia is the growth of breast tissue in men.

It’s an extremely rare side effect for SARMs, and typically more common from AAS. It’s’ caused by an imbalance between estrogen and testosterone.

Men with a history of gyno during puberty are at risk of redeveloping it on ACP-105, or any other PED that alters their hormonal balance.

Hair Shedding

Hair shedding from SARMs is rare, with some exceptions. It’s always temporary and fully reversible.

ACP-105 is very unlikely to cause hair shedding, just like Andarine and Ostarine. I have yet to come across a report of this instance.

Nonetheless, theoretically, it is still possible – but very, very unlikely.


Another super rare side effect that some people get. It’s unpredictable, but can easily be dealt with and mitigated.

Dosage Protocols

You will find many experimental dosing protocols if you start cruising through forums and Reddit.

The protocol I will share with you below is what 90% of the successful users online ran. This is considered the safe and “optimal” dosage for ACP-105. As previously stated, many have compared the gains from this protocol to that of a high-dose S4 cycle.

ACP-105 should be taken at a dosage of 10-20mg/day for 8 to 12 weeks, depending on if you’re cutting or bulking. 8-week cycles for bulks, 12-week cycles for cuts (max).

As the half-life of ACP-105 is still unclear, the dosage should be split and taken on 2 to 3 separate occasions throughout the day to ensure stable blood molecule levels. Once in the morning, once at noon, and once at night. 

Example Cycle


ACP-105 Dosage

Week 1

10 - 20 mg/day

Week 2

10 - 20 mg/day

Week 3

10 - 20 mg/day

Week 4

10 - 20 mg/day

Week 5

10 - 20 mg/day

Week 6

10 - 20 mg/day

Week 7

10 - 20 mg/day

Week 8

10 - 20 mg/day

PCT for ACP-105

ACP-105 doesn’t always require a PCT, as the level of suppression it causes is mild and most users bounce back to baseline within 4 weeks after their cycle.

Unfortunately, this isn’t the case for everyone, so you should never bet on it. To put yourself in the best possible position to recover in case you do get suppressed, have a SERM at hand just in case.

After finishing your ACP-105 cycle ideally do bloodwork to determine the need for a PCT. Get the following markers checked:

  • Total Testosterone & LH levels

Additionally, you may experience symptoms of suppression which is another valid signal indicating the need for a PCT.

To determine easily whether you need one or not, I’ve made the table below:


Symptoms of Suppression


Total Testosterone & LH within reference range (even if close to bottom)



Total Testosterone & LH within reference range (even if close to bottom)



Total Testosterone & LH below reference range



Can't Do Bloodwork (For Whatever Reason)



Can't Do Bloodwork (For Whatever Reason)




PCT for mildly suppressive SARMs in the category of ACP requires the use of any single SERM at a low dose for 3 weeks. For ACP-105 any SERM can be used as a PCT. I would personally choose between Tamoxifen, Toremifene, or Enclomiphene for optimal results.

I would avoid Clomiphene or Raloxifene, though they will still work if you can’t get any of the others.

This will be more than enough to get your levels back to baseline after an ACP-105 cycle if you fall into the minority of cases that end up needing a PCT.

Reference the table below for a dosing protocol for every SERM choice:
























Where to Buy ACP-105?

I recommend buying ACP-105 from an established and well-known vendor, that’s stood the test of time, and proven their legitimacy with good reviews and community support. Even though it’s unlikely to get fake stuff nowadays looking at how merciless the community is in calling out BS, it can still happen if you’re new to the space.

Thus these are my recommended sources for the highest quality ACP-105 out there, HPLC tested, and widely known and respected:

  • US – Chemyo |POP10 for 10% discount
  • EU & UK – CamoChem | POP20 for 20% discount

Pre-clinical research

The following academic studies collectively provide insights into the metabolism, effects, and detection of ACP-105, contributing to a better understanding of this research chemical in the context of doping control and potential therapeutic use.

What you read here is just a summary, you can find the full links in the references section at the very end of the article.

Identification of equine in vitro metabolites of ACP-105 [1]

In the first study, researchers investigated the in vitro metabolism of ACP-105 and other non-steroidal selective androgen receptor modulators (SARMs) in equine liver microsomes. They used liquid chromatography coupled with mass spectrometry for metabolite identification. For ACP-105, a total of twelve metabolites were identified, shedding light on its equine metabolism. This information is crucial for the detection of ACP-105 in doping control samples.

Identification of in vivo metabolites of ACP-105 in rats [2]

The second study focused on the in vivo metabolism of ACP-105 in rats. After oral administration of ACP-105, researchers collected urine samples and identified seven major phase-I metabolites. These metabolites, including monohydroxylated and bishydroxylated forms of ACP-105, were detectable in urine for several days post-administration. This information is essential for sports drug testing programs to detect the use of ACP-105.

Effects of ACP-105 on female mice [3]

The third study explored the effects of ACP-105 on female mice, particularly regarding sensorimotor function and cued fear conditioning. The research showed that ACP-105 had a positive impact on these aspects, especially in irradiated female mice. It also mentioned changes in microtubule-associated protein 2 levels in the cortex, suggesting potential contributions to enhanced performance.

Investigation of equine in vivo and in vitro metabolites of ACP-105 [4]

This study investigated the metabolite profile of ACP-105 in horses after oral administration, as well as in in vitro models. Researchers identified a total of 21 metabolites, including novel glucuronides, in both plasma and urine. This comprehensive analysis provides valuable targets for doping control in equine sports.

Detection and identification of ACP-105 and its metabolites in equine urine [5]

The fifth study developed a selective LC-MS/MS method to detect ACP-105 and its metabolites in equine urine. A total of 19 metabolites were identified, suggesting that ACP-105 is prone to oxidation, resulting in various hydroxylated forms. This information can aid in evaluating the use and potential misuse of ACP-105 in sports.

Synthesis and characterization of ACP-105 as a nonsteroidal SARM [6]

This study introduced ACP-105 as a potent nonsteroidal selective androgen receptor modulator with partial agonist activity. It was developed through a screening process and showed promise in improving anabolic parameters in castrated male rats. The study also identified other compounds with potential applications, including antiandrogens.


In conclusion, ACP-105 is a promising SARM that has been gaining popularity as a safer and more powerful alternative to other SARMs like Andarine and Ostarine.

Although it has never undergone human clinical trials, anecdotal and pre-clinical data indicates that ACP-105 has many benefits, including increased muscle mass and strength, bone density, and recovery, with fewer side effects than other SARMs.

ACP-105 is also the smallest molecule among all SARMs, which makes it highly bioavailable and presents unique possibilities for sublingual, transdermal, and other applications.

However, it is relatively expensive, has a short half-life, and is hard to obtain. Lastly, ACP-105 is not for human consumption.

As more data and evidence emerge, this article will continue to be updated to provide the latest information on ACP-105.

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