Detection of black market follistatin 344.
Nine out of 17 black market follistatin 344 products tested contained the substance, with a detection limit of approximately 0.1 ng/mL in urine for a 10 mL sample.
Where it sits
this study against the rest of the follistatin-344 corpusSummary and findings
This study evaluated the presence of black market follistatin 344 (FS344) products and developed a detection method for serum and urine. Out of 17 tested products, 9 contained FS344, while others contained different growth-promoting peptides. The detection limit for FS344 in urine was approximately 0.1 ng/mL for a 10 mL sample.
Abstract
Follistatin, a myostatin-inhibiting protein, is prohibited according to chapter S4 of the "WADA 2019 List of Prohibited Substances and Methods". While currently no approved pharmaceutical formulations of follistatin are available, follistatin can be bought on the black market. Most of the products are labeled "follistatin 344" (FS344), a few "follistatin 315". A study on FS344 black market products was performed and an electrophoretic detection method for serum and urine developed. While only nine of the 17 tested products actually contained follistatin, in some of the others growth promoting peptides were found (e.g. MGF, GHRP-2). Surprisingly, all nine products contained His-tagged FS344 and a high degree of its oligomers. The detection method is based on immunomagnetic purification followed by SDS-PAGE and Western blotting with a monoclonal anti-His antibody. Alternatively, a monoclonal anti-follistatin antibody can be used. For immunoprecipitation (IP), a polyclonal anti-follistatin antibody is applied. An evaluation of suitable antibodies for IP and immunoblotting is also presented. Furthermore, practically all currently available follistatin standards were investigated. The detection limit of the method for black market FS344 in urine is ca 0.1 ng/mL for 10 mL. For a sample volume of 100 μL, an LOD of 5 ng/mL could be achieved for serum. Due to the presence of His-tags an unambiguous differentiation from endogenous follistatin is possible.
Background
The paper investigates the presence of follistatin-344 in black market sources, which is significant given the peptide's biological roles in muscle growth and regulation. Prior knowledge indicates that follistatin-344 is a potent inhibitor of myostatin, making it a target for illicit use in bodybuilding and performance enhancement. Understanding the prevalence and detection methods of this peptide in unregulated markets is crucial for public health and regulatory measures.
Methods
Not reported in abstract.
Results
Not reported in abstract.
Interpretation
Not reported in abstract.
Key findings
- Not reported in abstract.
Limitations
- Not reported in abstract.