Structure of steroids: what you need to know
How does it all start?
Everything is built on cyclopentane perhydrophenanthrene — a nucleus of 4 rings (A, B, C, D). This is the skeleton of all steroids, like a chassis in a car.
Modifications are attached to it. Depending on what’s added, you get either testosterone, trenbolone, or stanozolol.
What changes the molecule?
1. Esters (chains at the 17β position)
Makes it oily and extends the half-life.
Examples:
- Testosterone propionate — short ester, requires injection every day
- Testosterone enanthate — long ester, requires injection once every 5–7 days
2. Modifications of ring A
Increases potency, but puts pressure on the central nervous system.
Examples:
- 5α-reduction: testosterone converts to DHT (dihydrotestosterone)
- 19-nor: removal of the C19 methyl group produces nandrolone or trenbolone
3. Double bonds
Increases anabolic activity, but stresses the liver.
Examples:
- Double bond between C1 and C2 + chlorine at C4: testosterone becomes turinabol
- Double bond between C1 and C2: methandienone (Dianabol)
4. Methylation (C17α-alkylation)
Allows the compound to survive first-pass metabolism in the liver. But it stresses the liver — hence the hepatotoxicity.
Example:
- Adding a methyl group to position 17α creates oral steroids (Anavar, Winstrol, Anadrol)
5. Aromatization
If the C19 methyl group is present, the steroid can convert into estradiol (causes estrogenic side effects). If C19 is removed, aromatization doesn’t occur, but progesterone-related side effects become possible.
Examples:
- Testosterone can aromatize into estradiol
- 19-nor compounds (tren, deca) do not aromatize, but bind to progesterone receptors
A steroid is not a “miracle.” This is chemistry. If you don’t understand how it works — well, that’s on you!
Steroidify is the channel where we talk about pharm in a human way.
