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YK-11 is a SARM that acts as a gene-specific agonist of the androgen receptor (AR) in MDA-MB 453 cells. YK 11 works on a variety of different anabolic pathways. YK-11 has shown greater anabolic activity in vitro in C2C12 myoblasts than DHT [1, 2]. YK11 promoted a cascade of muscle growth and key myogenic regulatory factors in skeletal muscle tissue such as myogenic differentiation factor (MyoD), myogenic factor 5 (Myf5), to a significantly greater extent than DHT. This can in part explain why YK11 exerts its selective modulation of the AR. Unlike testosterone and most other androgen receptor mediated anabolic agents, YK-11 is orally bioavailable so it does not require injection for proper absorption. At this time YK-11 is for laboratory research use only and the side effects are not fully known.


YK11 Mechanism of Action


What really sets YK-11 apart is that a key component of its anabolic activity is modulated via expression of follistatin. They discovered this by co-administering anti-follistatin antibodies with YK 11 to measure the difference in effects [2]. Follistatin has been shown to promote insulin-stimulated glucose and amino acid uptake into skeletal muscle cells, improving insulin sensitivity directly and increasing skeletal muscle mass [3]. Follistatin proteins also block inhibitory ligands from binding to Transforming Growth Factor-ß [4].

Perhaps the most alluring effect of follistatin is binding and neutralizing of catabolic proteins Activin A, Activin B, and Myostatin. Unfortunately follistatin proteins themselves undergo rapid proteolysis and have limited bioavailability and half-life even when injected directly into a wasting muscle. YK-11 however stimulates the body to produce more follistatin proteins systemically and locally which may circumvent this shortfall of direct follistatin administration and promote muscle growth [2, 4].

Animal studies have investigated the effects of YK 11 as a potential treatment for sepsis-induced muscle wasting. Researchers observed protective effects on muscle tissue and organ tissue, as well as suppression of gram-negative bacteria induced cytokine inflammation. Mortality rate in eight-week old septic mice treated with YK-11 also decreased significantly. They concluded that this was due to the suppression of myostatin as well as an increase in the expression of the follistatin gene [5].


YK-11 Side Effects


Little is revealed in clinical studies regarding YK-11 side effects however anecdotal reports online indicate the potential for joint pain, mild male-pattern hair loss, and aggression. Due to its action upon the androgen receptor (AR) it is plausible that YK11 use or abuse may result in side effects commonly reported with the use of other anabolics, for example elevated hemoglobin or hematocrit, high blood pressure, insomnia, nausea, or liver damage. YK 11 is only approved for laboratory research purposes at this time and is not a dietary supplement.


Data on our YK-11 for sale


CAS Number: 1370003-76-1

Formula: C25H34O6

Molar Mass: 430.541 g/mol

Class: Myostatin Inhibitor, Selective Androgen Receptor Modulator

Experimental Application: Muscle tissue growth, Myostatin inhibition

Storage: Store in a cool dry place away from direct sunlight to maximize shelf life.

Cited Research: Sports Technology Labs Research Blog


  • 30ml Liquid YK 11 per bottle with 10 milligrams per milliliter.
  • Includes graduated 1mL glass pipette for convenient measurement.
  • Glass bottle with UV resistance to minimize degradation.
  • Tamper-proof seal to ensure safety in transit.
  • Less than 5% variance in concentration, guaranteeing consistency.
  • Formulated and packaged to prevent evaporation in storage.


This preparation is for laboratory research purposes only and is not approved by the FDA for human consumption. YK-11 IS NOT A DIETARY OR SPORTS SUPPLEMENT.


Why is Sports Technology Labs the best place to buy YK-11 online?


YK 11 is considered by many researchers to be one of the best SARMs for bulking and building lean body mass due to its activity in both the traditional androgen mediated growth pathway and the follistatin pathway. It’s not hard to find YK-11 for sale online, but Sports Technology Labs is the best place to buy YK-11 online because of our consistent, verifiable high quality, fast shipping, safer bottling and packaging, and our outstanding customer service and handling time. Our YK-11 is also available in pure powder form.

At Sports Technology Labs you can find the highest quality YK-11 for sale anywhere on the internet. When you buy SARMs from Sports Technology Labs you are choosing the highest quality ingredients. Minimum 98% pure compounds tested and certified by accredited American third party labs, suspended in USP grade (the highest grade) PEG400, bottled in America. Our products come in glass bottles with fixed glass droppers to prevent the leaching of unwanted plasticizers like BPA, and prevent contamination between uses with external measuring tools. We run a transparent business, with no discreet payment methods necessary and no misrepresentation of our products, only the highest quality research chemicals available online, secured by our 60-day money-back guarantee.

That’s why we are confident in our claim that we offer the best YK 11 for sale on the market today. And if you have any questions about our liquid YK11 products, you can also contact us and we’ll respond as soon as possible.


Abuse Warning


YK11 is an investigational compound still awaiting FDA approval and is not a dietary supplement. At Sports Technology Labs we are chemical suppliers, not medical doctors, and our expertise is sourcing and quality control. Sports Technology Labs does not encourage or condone consumer use of SARMs products, they are for research purposes only. Anecdotal reports online indicate YK 11 dosage of 10mg and 20mg per day used by many individuals. A YK11 dose of 50mg per day has even been reported by several bodybuilders in online forums. These dosages may not match those used in carefully designed medical research protocols and may pose a serious risk of adverse effects in users.

We consider the duplication of anecdotal protocols online to be a risky practice. SARMs should only be used under the supervision and direction of a medical doctor or designated research authority. We strongly discourage the use of SARMs for performance enhancement in sports and bodybuilding, and warn against “bro science” and peer consensus when making decisions about human health.



1. Kanno Y, Hikosaka R, Zhang SY, Inoue Y, Nakahama T, Kato K, Yamaguchi A, Tominaga N, Kohra S, Arizono K, Inouye Y (2011). “(17α,20E)-17,20-[(1-methoxyethylidene)bis(oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11) is a partial agonist of the androgen receptor”. Biological & Pharmaceutical Bulletin. 34 (3): 318–23. PMID 21372378  https://pubmed.ncbi.nlm.nih.gov/21372378/
2. Kanno Y, Ota R, Someya K, Kusakabe T, Kato K, Inouye Y (2013). “Selective androgen receptor modulator, YK11, regulates myogenic differentiation of C2C12 myoblasts by follistatin expression”. Biological & Pharmaceutical Bulletin. 36 (9): 1460–5. PMID 23995658. https://pubmed.ncbi.nlm.nih.gov/23995658/
3. Han X, Moller LLV, et al. Mechanisms involved in follistatin-induced hypertrophy and increased insulin action in skeletal muscle. J Cachexia Sarcopenia Muscle. 2019 Aug 11. doi: 10.1002/jcsm.12474 https://pubmed.ncbi.nlm.nih.gov/31402604/
4. Castonguay R, Lachey J, Wallner S, et al. Follistatin-288-Fc Fusion Protein Promotes Localized Growth of Skeletal Muscle. J Pharmacol Exp Ther. 2019 Mar;368(3):435-445. doi: 10.1124/jpet.118.252304. Epub 2018 Dec 18. https://jpet.aspetjournals.org/content/jpet/368/3/435.full.pdf
5. Su Jin Lee, Amal Gharbi, Joo Eun Shin, In Duk Jung, Yeong Min Park, Myostatin inhibitor YK11 as a preventative health supplement for bacterial sepsis, Biochemical and Biophysical Research

Liquid YK-11 – 10MG/ML

Additional information

Weight 3.0 oz

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