AEBM FOA Extension: System-Specific Burden Matrix of Anabolic-Androgenic Steroids - A Multiaxial Framework of Functional Yield and Biological Cost within the Functional Androgen Axis (FOA)

The use of anabolic-androgenic steroids (AAS) in performance and optimisation contexts is commonly interpreted through simplified dose-response paradigms that fail to account for system-level biological complexity. While supraphysiological androgen exposure reliably increases signal intensity within the Functional Androgen Axis (FOA), functional outcomes are constrained by system capacity and nonlinear burden accumulation across multiple physiological domains. This paper introduces the System-Specific Burden Matrix (AEBM) as a formal extension of the FOA framework. The AEBM integrates androgen signal intensity with compound-specific biological cost across seven system domains: Metabolic, Neuropsychiatric/HPA, Inflammatory, Hematologic, Local/Recovery, Hepatic and Cardiovascular structural. A quantitative construct, the Burden-to-Yield Ratio (BYR), expresses biological cost relative to functional return. Ten compounds - testosterone, nandrolone, trenbolone, boldenone, drostanolone, metenolone, oxandrolone, stanozolol, methandienone and oxymetholone - are analysed across all matrix dimensions. The matrix demonstrates that compounds generate distinct biological cost signatures disproportionate to their functional yield, and that optimisation requires managing burden-to-yield balance rather than maximising signal intensity. AEBM operates as a per-compound baseline model; multi-compound protocols are addressed in a companion publication (AEBM Stack Extension) which uses a recalibrated metric (Stack_BYR) not directly comparable to the per-compound BYR values in this document.