What is liver toxicity from oral anabolic steroids?

In one line

Liver toxicity from oral anabolic steroids is liver damage, such as blocked bile flow, caused by swallowed steroids whose structure was changed so the liver clears them less.

What is liver toxicity from oral anabolic steroids?
Where 'pills are bad for the liver' comes from
Talk about steroids often comes with the line 'the pills are bad for your liver'. The steroids here are anabolic steroids, used to build muscle. Why are the swallowed kind linked to the liver?
In short
Swallowed steroids harming the liver
'Oral' means taken by mouth, and 'liver toxicity' means a drug harming the liver. Oral anabolic steroids are made with a changed structure so the liver does not clear them easily. This changed structure is the one most often reported with liver damage.
What are anabolic steroids?
Drugs that copy the male hormone
A hormone is a substance made in one part of the body that travels in the blood and carries a signal to another part. Anabolic steroids are lab-made drugs that copy the main male hormone, 'testosterone', and they build muscle. Some are swallowed as pills and some are injected.
The path of a swallowed drug
It passes the liver before reaching the body
A swallowed drug enters the blood from the gut and passes through the liver before it spreads through the body. The liver removes poisons, so at this point it breaks down much of the drug. Breaking down means cutting into small pieces and removing. If testosterone itself is swallowed, less than 4% of the amount taken reaches the body's blood.
17α-alkylation
A structure changed so the liver breaks it down less
To make it work when swallowed, a small carbon piece is attached at spot number 17 of the testosterone molecule; these are '17α-alkylated' steroids. With this change, the liver breaks them down less, so more stays in the body after swallowing. The price is a higher risk of liver damage.
Cholestasis
Bile gets stuck in the liver
The liver makes 'bile', a digestive fluid that helps digest fat, and sends it to the gut. When this flow is blocked or slowed and bile builds up in the liver, it is called 'cholestasis'. This is the typical liver damage caused by 17α-alkylated steroids.
Jaundice and itching
Skin and the whites of the eyes turn yellow
Cholestasis brings 'jaundice', in which the skin and the whites of the eyes turn yellow, along with strong itching. In a group of people whose livers were damaged by bodybuilding supplements, all developed jaundice. The jaundice usually took about 3 months to clear.
Blood pockets in the liver
Small pockets filled with blood
A disease in which many small blood-filled pockets form in the liver has been reported in people who used anabolic steroids. It usually causes no symptoms and is found by chance. Cases in which a pocket burst and blood collected inside the belly have also been reported.
Liver tumors
Tumors and liver cancer in long-term users
In people who used anabolic steroids for a long time, cases of non-cancer liver tumors and of liver cancer have been reported. Most came from 17α-alkylated steroids, but they have also been reported with injected testosterone.
Common misconception
If it is sold as a 'supplement', is the liver safe?
No. When the products taken by people whose livers were damaged by bodybuilding supplements were analyzed, about 4 out of 5 contained steroids different from those on the label. Most of them were sold as supplements but were really oral steroids.
Summary
The cost of a structure the liver breaks down less
Oral anabolic steroids are drugs whose structure was changed so the liver breaks them down less and they work when swallowed, and that structure is linked to liver damage such as cholestasis and liver tumors. They also hide in products sold as supplements. Related terms: anabolic steroids, jaundice, SARMs.