Anabolic Steroids and Cancer

Anabolic-androgenic steroids are lab-made versions of testosterone. Testosterone is the main male sex hormone. These drugs carry two effects that cannot be pulled apart. The anabolic effect builds muscle. The androgenic effect drives male sex traits, in men and in women. Chemists have tried for decades to split the two. It has not worked.

They are real medicines. Oxandrolone, sold as Oxandrin, is FDA-approved for several uses:

• To help people regain weight after major surgery, long infection, or severe injury.
• To offset protein loss during long courses of corticosteroids.
• To ease the bone pain that often comes with osteoporosis.

The same drugs are widely misused. Common oral forms are Anadrol (oxymetholone) and Anavar (oxandrolone). Also Dianabol (methandienone) and Winstrol (stanozolol). Injected forms include Deca-Durabolin (nandrolone decanoate) and Depo-Testosterone (testosterone cypionate). All are Schedule III controlled substances under the Anabolic Steroids Control Act of 1990.

Medical doses and misuse doses are not on the same scale. People who misuse these drugs may take 10 to 100 times the dose used to treat a medical condition.

Misuse follows patterns with their own names:

• Cycling. Taking doses over a set period, stopping, then starting again.
• Stacking. Taking two or more steroids at once. Users may mix oral and injected forms. Some add compounds meant for animals.
• Pyramiding. A cycle of 6 to 12 weeks. Doses start low, rise, then taper to zero.
• Plateauing. Staggering or swapping steroids to avoid tolerance.

None of these patterns has been shown to work the way users believe. Steroid users report taking about 11 performance-enhancing substances a year on average.

This is the most specific evidence available. It sits in a boxed warning. That is the most serious warning FDA can require on a prescription drug.

The oxandrolone label warns about peliosis hepatis. In this condition, liver tissue is replaced by blood-filled cysts. Spleen tissue is sometimes affected too. The label is blunt about how it presents. Sometimes the cysts appear with almost no sign of liver trouble. At other times they cause liver failure. They often go unrecognized until liver failure or bleeding inside the belly develops. Stopping the drug usually clears the lesions completely.

The same warning covers tumors. Liver cell tumors are reported. Most are benign and androgen-dependent. But fatal malignant tumors have been reported. Stopping the drug often makes the tumor shrink or stop growing.

Then comes the line that matters most for safety. Liver tumors tied to androgens or anabolic steroids hold far more blood vessels than other liver tumors. So they may stay silent until dangerous bleeding starts inside the belly.

That is the harm in one picture. A tumor you cannot feel. An organ with no pain nerves inside it. And blood vessels that break easily.

Three more appear in the approved labeling:

• Oxandrolone is contraindicated in known or suspected cancer of the prostate or the male breast.
• It is contraindicated in women with breast cancer who have high blood calcium. These drugs can speed up bone breakdown.
• Older patients on androgenic anabolic steroids may face higher risk of prostate enlargement and prostate cancer.

The label also states, in capital letters, that anabolic steroids have not been shown to improve athletic ability.

The National Institute on Drug Abuse lists three liver effects of steroid misuse. They are liver damage, tumors, and peliosis hepatis. NIDA notes the cysts can rupture. That causes internal bleeding, and in rare cases death.

NIDA describes a second route as well. These drugs may act on the hormone system to raise the risk of testicular cancer. The risk appears higher when they are combined with insulin-like growth factor.

A caveat belongs here. Most long-term human data come from case reports, not formal population studies. One review found 19 deaths in published case reports between 1990 and 2012. Many of those users took other drugs too, so cause is hard to pin down. Serious effects are likely underreported. They can appear years later.

IARC has evaluated androgenic anabolic steroids. That review appears in Supplement 7 to its Monographs, published in 1987. Oxymetholone was reviewed on its own in Volume 13, in 1977.

Many users start with oral steroids and later switch to injected ones. Injected forms do less damage to the liver. Oral forms leave the body faster, so users worried about drug testing prefer them.

Injection adds a risk that has nothing to do with the drug. Nonsterile technique and shared needles spread HIV and hepatitis B and C. Long-term hepatitis B and C are themselves leading causes of liver cancer. So an injecting user can reach the same organ by two separate roads. Our page on liver cancer covers those causes.

For scale, the American Cancer Society projects 42,340 new liver and bile duct cancers in the United States in 2026, and 30,980 deaths; SEER republishes both. NCI's own SEER measurement puts the lifetime chance of a liver or bile duct diagnosis at about 1.1%.

Good national numbers are scarce. Many drug surveys leave steroids out. The Monitoring the Future Survey does ask. In 2022, an estimated 0.8% of 8th graders reported misusing steroids in the past 12 months. So did 0.5% of 10th graders and 1.3% of 12th graders.

Misuse is often tied to muscle dysmorphia. That is a form of body dysmorphic disorder built around a belief that one's muscles are too small.

There is a concrete question for anyone who takes these drugs outside medical care, or once did. Ask a clinician whether liver imaging and liver blood tests are warranted. Peliosis hepatis and androgen-linked liver tumors look like nothing until they do not. The label's own words are that they often go unrecognized until bleeding occurs.

For how carcinogen labels get built, see what a carcinogen is. For what a label does and does not promise, see hazard versus risk.

• National Institute on Drug Abuse, Anabolic Steroids, accessed August 6, 2026
• DailyMed, Oxandrin (oxandrolone) FDA label, accessed August 6, 2026
• IARC, Cumulative Cross Index to the Monographs, accessed August 6, 2026
• NCI SEER Program, Cancer Stat Facts: Liver and Bile Duct Cancer, accessed August 6, 2026