T Nation

Androgen Binding Affinity at Androgen Receptor

Do all anabolics have a stronger binding affinity than estrogen at the Androgen receptor ?
If you know which ones are weaker or stronger at doing this please explain,

Yes, any anabolic steroid will have a far higher affinity for the AR compared to estrogen

DHT/DHT derivatives tend to have a far more pronounced binding affinity… but there are exceptions to this… and tren

An example of an AAS that has a relatively weak affinity for the AR would be dbol

Ok and what about primo hows the binding affinity on that ?
And does primo lower shbg a lot ?

Is this the reason dbol causes E2 issues? Because more estrogen is allowed to bind on the receptor than other steroids?

No, very few AAS have less AR binding affinity compared to estradiol. The only exceptions I can think of would be ethisterone, tibolone… danazol coming close… they’re hormonal progestins/AAS used to treat gynaecological disorders (such as premenopausal/postmenopausal symptomatology).

There’s actually a list on wikipedia I can copy/paste here

Pharmacological properties of major anabolic steroids show

Relative affinities (%) of anabolic steroids and related steroids hide Compound Chemical name PR AR ER GR MR SHBG CBG
Androstanolone DHT 1.4–1.5 60–120 <0.1 <0.1, 0.3 0.15 100 0.8
Boldenone Δ1-T <1 50–75 ? <1 ? ? ?
Danazol 2,3-Isoxazol-17α-Ety-T 9 8 ? <0.1a ? 8 10
Dienolone ∆9-19-NT 17 134 <0.1 1.6 0.3 ? ?
Dimethyldienolone ∆9-7α,17α-DiMe-19-NT 198 122 0.1 6.1 1.7 ? ?
Dimethyltrienolone ∆9,11-7α,17α-DiMe-19-NT 306 180 0.1 22 52 ? ?
Drostanolone 2α-Me-DHT ? ? ? ? ? 39 ?
Ethisterone 17α-Ety-T 35 0.1 <1.0 <1.0 <1.0 25–92 0.3
Ethylestrenol 3-DeO-17α-Et-19-NT ? ? ? ? ? <1 ?
Fluoxymesterone 9α-F-11β-OH-17α-Me-T ? ? ? ? ? ≤3 ?
Gestrinone ∆9,11-17α-Ety-18-Me-19-NT 75–76 83–85 <0.1, 3–10 77 3.2 ? ?
Levonorgestrel 17α-Ety-18-Me-19-NT 170 84–87 <0.1 14 0.6–0.9 14–50 <0.1
Mestanolone 17α-Me-DHT 5–10 100–125 ? <1 ? 84 ?
Mesterolone 1α-Me-DHT ? ? ? ? ? 82–440 ?
Metandienone ∆1-17α-Me-T ? ? ? ? ? 2 ?
Metenolone ∆1-1-Me-DHT ? ? ? ? ? 3 ?
Methandriol 17α-Me-A5 ? ? ? ? ? 40 ?
Methasterone 2α,17α-DiMe-DHT ? ? ? ? ? 58 ?
Methyldienolone ∆9-17α-Me-19-NT 71 64 <0.1 6 0.4 ? ?
Methyltestosterone 17α-Me-T 3 45, 100–125 ? 1–5 ? 5–64 <0.1
Methyl-1-testosterone ∆1-17α-Me-DHT ? ? ? ? ? 69 ?
Metribolone ∆9,11-17α-Me-19-NT 208–210 199–210 <0.1 10–26 18 0.2–0.8 ≤0.4
Mibolerone 7α,17α-DiMe-19-NT 214 108 <0.1 1.4 2.1 6 ?
Nandrolone 19-NT 20 154–155 <0.1 0.5 1.6 1–16 0.1
Norethandrolone 17α-Et-19-NT ? ? ? ? ? 3 ?
Norethisterone 17α-Ety-19-NT 155–156 43–45 <0.1 2.7–2.8 0.2 5–21 0.3
Norgestrienone ∆9,11-17α-Ety-19-NT 63–65 70 <0.1 11 1.8 ? ?
Normethandrone 17α-Me-19-NT 100 146 <0.1 1.5 0.6 7 ?
Oxandrolone 2-Oxa-17α-Me-DHT ? ? ? ? ? <1 ?
Oxymetholone 2-OHMeEne-17α-Me-DHT ? ? ? ? ? ≤3 ?
RU-2309 (17α-Me-THG) ∆9,11-17α,18-DiMe-19-NT 230 143 <0.1 155 36 ? ?
Stanozolol 2,3-Pyrazol-17α-Me-DHT ? ? ? ? ? 1–36 ?
Testosterone T 1.0–1.2 100 <0.1 0.17 0.9 19–82 3–8
1-Testosterone ∆1-DHT ? ? ? ? ? 98 ?
Tibolone 7α-Me-17α-Ety-19-N-5(10)-T 12 12 1 ? ? ? ?
Δ4-Tibolone 7α-Me-17α-Ety-19-NT 180 70 1 <1 2 1–8 <1
Trenbolone ∆9,11-19-NT 74–75 190–197 <0.1 2.9 1.33 ? ?
Trestolone 7α-Me-19-NT 50–75 100–125 ? <1 ? 12 ?
Notes: Values are percentages (%). Reference ligands (100%) were progesterone for the PR, testosterone for the AR, estradiol for the ER, dexamethasone for the GR, aldosterone for the MR, dihydrotestosterone for SHBG, and cortisol for CBG. Footnotes: a = 1-hour incubation time (4 hours is standard for this assay; may affect affinity value). Sources: See template.

Relative affinities (%) of methylestradiol and related steroids hide|Compound|PR|AR|ER|GR|MR|SHBG|CBG|
| — | — | — | — | — | — | — | — |
|Estradiol|2.6|7.9|100|0.6|0.13|8.7|<0.1|
|Ethinylestradiol|15–25|1–3|112|1–3|<1|?|?|
|Methylestradiol|3–10, 15–25|1–3|67|1–3|<1|?|?|
|Methyltestosterone|3|45, 100–125|?|1–5|?|5|?|
|Normethandrone|100|146|<0.1|1.5|0.6|?|?|
|Sources: Values are percentages (%). Reference ligands (100%) were progesterone for the PR, testosterone for the AR, E2 for the ER, DEXA for the GR, aldosterone for the MR, DHTfor SHBG, and cortisol for CBG. Sources: [13][6][14][15]|