All anabolic androgenic steroids share a common 4-ring steroidal scaffold (three cyclohexane rings + one cyclopentane ring). Class differences arise from structural modifications that alter AR binding affinity, aromatization susceptibility, 5α-reduction products, bioavailability, and metabolic half-life.
| Compound | Class | A:A Ratio | Aromatizes | 5α-Reduction Product | Progestin | Route |
|---|---|---|---|---|---|---|
| Testosterone | Testosterone ester | 100:100 | → E2 | → DHT (↑AR affinity) | No | Injectable |
| Nandrolone DECA | 19-nor | 125:37 | Minimal → E1 | → DHN (↓AR affinity) | Yes (~20% P4) | Injectable |
| Trenbolone | 19-nor triene | 500:500 | No | None (Δ11 prevents) | Yes (~60% P4) | Injectable |
| MENT | 7α-Me-19-nor | 650:250 | → 7α-Me-E2 | → 7α-Me-DHN (active) | Yes (strong) | Injectable |
| Equipoise | Δ1-testosterone | 100:50 | Partial (~50% T) | → 5α-dihydroboldenone | No | Injectable |
| Dianabol | 17α-Me-Δ1-Test | 210:60 | → 17α-Me-E2 | → 5α-dihydromethandrostenolone | No | Oral + Injectable |
| Anavar | DHT 2-oxa | 322:24 | No | Already 5α-reduced (DHT base) | No | Oral |
| Anadrol | DHT 2-OH-Me | 320:45 | No (but ER agonist) | Already 5α-reduced (DHT base) | No | Oral + Injectable |
| Winstrol | DHT pyrazole | 320:30 | No | Already 5α-reduced (DHT base) | No | Oral + Injectable |
| Masteron | 2α-Me-DHT | 62:25 | No (inhibits CYP19A1) | Already 5α-reduced (DHT base) | No | Injectable |