A “methylated” oral steroid has a small carbon group added at the 17-alpha position so it survives the liver when swallowed. That change is why the tablet works, and also why it is harder on the liver and cholesterol.
- Most oral steroids are 17-alpha-alkylated: Anavar, Dianabol, Winstrol, Anadrol, Superdrol and more.
- They lower HDL cholesterol more than injectables and raise liver enzymes.
- Short use, single compounds and bloodwork limit the risk.
If you read about oral steroids for long, you will see the word “methylated” or “17-aa” again and again, usually next to warnings about the liver. It is worth understanding what it actually means, because it explains most of the differences between pills and injections.
The chemistry in plain language
Swallowed testosterone does not get very far. Everything absorbed from your gut goes first to the liver, which breaks most hormones down before they reach the rest of the body. That is called first-pass metabolism, and it is why plain testosterone barely works as a pill.
Chemists found a workaround in the 1930s: add a methyl group (a carbon with three hydrogens) or an ethyl group at the 17th carbon of the steroid, on the “alpha” side. This is 17-alpha-alkylation. It blocks the liver enzyme that would normally inactivate the hormone at that spot, so much more survives and reaches the bloodstream.
The catch is that the liver now has to deal with a molecule it struggles to break down. That is where the strain comes from.
Which steroids are methylated?
| 17-alpha-alkylated (methylated) | Not 17-alpha-alkylated |
|---|---|
| Oxandrolone (Anavar) | Mesterolone (Proviron), methylated at a different spot |
| Methandienone (Dianabol) | Testosterone undecanoate capsules, absorbed through the lymph |
| Stanozolol (Winstrol tablets) | All injectable esters (enanthate, cypionate, decanoate) |
| Oxymetholone (Anadrol) | Trenbolone and nandrolone injectables |
| Methasterone (Superdrol) | |
| Fluoxymesterone (Halotestin) | |
| Chlorodehydromethyltestosterone (Turinabol) | |
| Methyltestosterone, metribolone |
Injectable stanozolol is also 17-alpha-alkylated, so it shares some of the oral version’s effects on lipids even though it skips first-pass metabolism.
What it means for your liver
Methylated orals commonly raise ALT and AST, and can slow bile flow (cholestasis), causing itching and jaundice. Rarely, long-term high-dose use has been linked to blood-filled liver cysts (peliosis hepatis) and liver tumours. Strain rises with dose, duration and combining orals. Our guide to liver support during orals covers monitoring and what helps.
What it means for your heart
Because they pass through the liver at high concentration, methylated orals have an outsized effect on hepatic lipase, the enzyme that breaks down HDL cholesterol. HDL can drop by half or more, even with compounds people think of as mild, like Anavar or Winstrol. Read more in steroids and cholesterol.
Why methylated orals are used for short periods
Because of these effects, oral steroids are generally used for shorter periods than injectables, and combining two orals is widely discouraged even within the bodybuilding community. Medical use reflects this too. Oxandrolone, for example, was prescribed at 2.5–20 mg a day for limited periods to help patients regain weight after surgery, burns or infection, with liver tests along the way.
Methylation and potency on paper
You will sometimes see oral steroids ranked by “anabolic to androgenic ratio,” numbers taken from old animal studies. They are a poor guide to real-world effects, and they say nothing about liver or heart strain. Two compounds with impressive ratios on paper can have very different side-effect profiles in people. Oxandrolone, for example, has a high ratio and a reputation for being mild, yet it still lowers HDL sharply. Methasterone (Superdrol) and oxymetholone (Anadrol) are considered among the hardest on the liver. When comparing orals, look at liver and lipid effects first, then everything else.
Lowering the risk
- Get baseline liver enzymes and a lipid panel before starting, and retest part way through.
- Use one oral at a time and keep the run short.
- Avoid alcohol and high doses of acetaminophen.
- Allow enzymes and HDL to return to baseline before considering another oral.
- Stop at the first sign of jaundice, dark urine or persistent itching.
Our Canadian bloodwork guide explains how to arrange testing through your doctor, LifeLabs or Dynacare.
Comparing your options
Every oral product on SteroidsCanada lists its strength per tablet and whether it is 17-alpha-alkylated in the specifications. The compound profiles compare liver and lipid effects side by side, and the oral steroids category shows every tablet we carry from Zionova and Genetix.
Frequently asked questions
Is Anavar methylated?
Yes. Oxandrolone is 17-alpha-alkylated. It is considered milder on the liver than Anadrol or Superdrol, but it still lowers HDL cholesterol substantially.
Are any oral steroids not methylated?
Mesterolone (Proviron) and testosterone undecanoate capsules are not 17-alpha-alkylated, so they are gentler on the liver.
Why are injectable steroids easier on the liver?
Injected hormones enter the bloodstream directly instead of passing through the liver first, and most are not 17-alpha-alkylated.
Photo: rawpixel (public domain).
General information, not medical advice. Talk to a doctor before using any oral steroid and monitor your liver with bloodwork.
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