Warning letter · FDA Warning Letters

Musclepower Enterprise Ltd. dba MONSTER KING and GE LABS: FDA Warning Letter 719339 (Dec 12, 2025)

Agency action: Dec 12, 2025Record ID: fda_warning_-fed423a57febe67d
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What happened

Original notice title

Musclepower Enterprise Ltd. dba MONSTER KING and GE LABS MARCS-CMS 719339, December 12, 2025

From the archived source record

As described below, these products are unapproved new drugs and were introduced or delivered for introduction into interstate commerce in violation of sections 505(a) and 301(d) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. 355(a) and 331(d). Furthermore, your “GE Labs Ykarine” product is a misbranded drug under section 502 of the FD&C Act, 21 U.S.C. 352, and was introduced or delivered for introduction into interstate commerce in violation of section 301(a) of the FD&C Act, 21 U.S.C. 331(a). FDA confirmed through laboratory analysis that a sample of your “GE Labs Ykarine” product contains undeclared trendione (estra-4,9,11-triene-3,17-dione), which is an anabolic steroid and is classified as a schedule III-controlled substance by the U.S. Drug Enforcement Administration (DEA). 1 As described below, FDA has safety concerns about anabolic steroids such as trendione (estra-4,9,11-triene-3,17-dione). As described in FDA's August 2022 Policy Regarding N-acetyl-L-cysteine: Guidance for Industry , 2 we intend to exercise enforcement discretion with respect to the sale and distribution of NAC-containing products that are labeled as dietary supplements and would be lawfully marketed dietary supplements if NAC were not excluded from the definition of “dietary supplement” and are not otherwise in violation of the FD&C Act. However, as the guidance notes, the enforcement discretion policy does not apply to NAC-containing products that are adulterated or misbranded under the FD&C Act (other than those misbranded only because they contain NAC and are labeled as dietary supplements). As discussed in further detail below, your “GE Labs Ykarine” product is misbranded under section 502(a) of the FD&C Act because the label does not declare that the product contains trendione (estra-4,9,11-triene-3,17-dione), a controlled substance.

What the official notice says to do

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Status and source details

Status recorded in the archive
No closeout listed in FDA table
Source checked
Jul 16, 2026
Record revision
8eea7e7dfe03

This is a dated record. Its current status may have changed since the source was captured. A record applies to its stated scope; it is not a safety rating for every product from a company.

Sources, dates, and coverage →

What is affected

Product
GE Labs Ykarine; GE Labs MK 677; MYOSTATIN INHIBITOR; INCREASE MUSCLE MASS; BOOST STRENGTH & ENDURANCE; 11-triene-3; 17-dione)
Company
Musclepower Enterprise Ltd. dba MONSTER KING and GE LABS
Lot / identifier
The source does not specify this field.
Market / distribution
The source does not specify this field.