Methylclostebol MCLOS

A steroid that has shown up as a hidden, undeclared ingredient in tainted supplements, causing athletes to fail drug tests without knowingly taking it. There's no legitimate human research on it — its risks are assumed from its close relationship to a similar steroid.

Also known as Promagnon

Effects Build muscle

Routes Oral

Legal status Unapproved / investigational

WADA Banned at all times

3D Molecular Structure of C₂₀H₂₉ClO₂

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Chemistry

Formula: C20H29ClO2
Molar mass: 336.9
CAS: 5785-58-0
PubChem CID: 227107

Reported dosing

Limited data

What has been reported in the literature and by users. This is a record of what is done, not a recommendation.

Typical dose Not established (no legitimate human use)

Reported range Underground/contaminant reports vary; has appeared as an undisclosed contaminant in some supplement products

Route Oral

Frequency Not established

Duration Not established

A designer anabolic steroid with no approved human use; has been the subject of doping cases where athletes were exposed unknowingly through contaminated supplements.

Where this comes from Anti-doping/case literature

Human data for this compound is limited. Read the figures above as a record of reported use rather than established dosing.