Steroids change how your body builds tissue, manages inflammation, and regulates hormones. The word “steroids” actually covers two very different types of drugs: anabolic steroids, which mimic testosterone to increase muscle size and strength, and corticosteroids, which calm your immune system and reduce inflammation. Both reshape your body’s internal chemistry in powerful ways, and both carry real risks when used long-term or without medical supervision.
Two Types of Steroids, Two Different Jobs
Anabolic steroids are synthetic versions of testosterone. They’re prescribed for conditions where the body doesn’t produce enough testosterone on its own, but they’re far more widely known for non-medical use. An estimated 3 to 4 million Americans use unregulated performance-enhancing drugs, and that number is likely a significant undercount since federal health agencies don’t track adult use the way they do other substances.
Corticosteroids are a completely different class of drug. They treat inflammatory and autoimmune conditions like rheumatoid arthritis, lupus, asthma, eczema, vasculitis, and severe allergic reactions. They’re also used to help the body heal after injuries like bursitis, tendinitis, and carpal tunnel syndrome. When people talk about being “on steroids” for a medical condition, they almost always mean corticosteroids.
How Anabolic Steroids Build Muscle
Anabolic steroids enter your cells and bind to androgen receptors. Once bound, the steroid-receptor pair moves into the cell’s nucleus, attaches to your DNA, and switches on genes that ramp up protein production. The result is faster muscle protein synthesis and a positive nitrogen balance, meaning your muscles retain more of the building blocks they need to grow.
There’s a second mechanism at work too. Your muscles contain satellite cells, which are essentially repair-and-growth cells that sit dormant until they’re activated. These satellite cells have their own androgen receptors, and steroids stimulate them to multiply. This creates more raw material for muscle repair and growth, which is part of why steroid-assisted gains happen faster than what training alone can produce.
The shape of each steroid molecule matters. Different steroids cause the receptor to fold into slightly different configurations, and each configuration attracts a different set of helper proteins. These helper proteins either amplify or dampen the signal to your DNA. That’s why various anabolic steroids produce somewhat different effects on muscle, bone, and other tissues, even though they all work through the same basic receptor.
How Corticosteroids Reduce Inflammation
Corticosteroids work through a different receptor entirely. They bind to glucocorticoid receptors in the cell’s cytoplasm. The receptor pair then travels to the nucleus, where it does something unusual: instead of activating genes, it primarily shuts them down. It blocks transcription factors (the proteins that switch inflammatory genes on) by physically binding to them and preventing them from doing their job.
This suppresses a wide range of inflammatory signals your body normally produces during an immune response. The practical effect is less swelling, less redness, less pain, and a calmer immune system overall. That’s enormously useful when your immune system is attacking your own tissues (as in lupus or rheumatoid arthritis) or overreacting to a trigger (as in asthma or severe allergies). It’s also why corticosteroids can leave you more vulnerable to infections: the same immune activity they’re dialing down is what normally fights off bacteria and viruses.
What Happens to Your Hormones
Your brain constantly monitors hormone levels through a feedback loop connecting the hypothalamus, pituitary gland, and gonads. When you introduce synthetic testosterone, your brain detects the elevated levels and responds by shutting down its own signals to produce more. Studies show this suppression is nearly complete: levels of the hormones that stimulate the testes (LH and FSH) drop to undetectable in most users.
While you’re taking anabolic steroids, this doesn’t feel like a problem because the synthetic hormones are doing the job. The trouble starts when you stop. Your body’s natural production has been idling, and it doesn’t restart immediately. During this gap, you can experience low energy, reduced sex drive, mood changes, and in men, testicular shrinkage. How quickly natural production recovers depends on how long and how heavily steroids were used, but for some long-term users, full recovery takes months or never fully occurs.
Cardiovascular Effects
Anabolic steroids push your cardiovascular system in several harmful directions at once. They shift your cholesterol profile toward a pattern associated with heart disease: lower HDL (the protective type) and higher LDL (the harmful type). They raise blood pressure. They promote blood clotting. And they can cause the heart’s left ventricle to thicken and stiffen, a condition called left ventricular hypertrophy that makes the heart less efficient at pumping blood.
These changes don’t just increase risk on paper. Steroid users develop coronary atherosclerosis, the buildup of plaque in the arteries feeding the heart, at rates that wouldn’t be expected for their age. Some of these cardiac changes appear to result from steroid-induced high blood pressure, but researchers have identified evidence of direct damage to heart muscle cells as well, suggesting the drugs are toxic to the heart through more than one pathway.
Visible Physical Changes
Some of the most noticeable effects of anabolic steroids show up on the outside. Severe acne is common among users of both sexes, driven by the same androgen activity that enlarges oil glands and increases sebum production during puberty. In men, excess testosterone gets partially converted to estrogen, which can cause breast tissue to grow, a condition called gynecomastia. In women, anabolic steroids can cause hair loss on the head that may be permanent even after stopping the drugs, along with deepening of the voice and growth of facial hair.
Psychological and Mood Effects
The mental effects of anabolic steroids are harder to see but no less significant. The stereotype of “roid rage” is an oversimplification, but the underlying pattern is real. Research on steroid-using athletes has found elevated levels of depressive, anxious, and antisocial personality traits compared to non-users. In one study of female athletes, 56% of steroid users met clinical criteria for six or more psychological disorders.
These findings don’t prove steroids caused every case of mental illness in users, since some people with pre-existing psychological vulnerabilities may be drawn to steroid use. But the pattern is consistent and shows up across multiple personality dimensions: higher rates of borderline, antisocial, depressive, and negativistic traits. The mood disruption tends to worsen during withdrawal, when the brain is adjusting to the sudden drop in hormones it had come to depend on.
Withdrawal and Recovery
Stopping steroids after long-term use triggers a withdrawal syndrome that can mimic adrenal insufficiency, the condition where your adrenal glands fail to produce enough cortisol. Symptoms include fatigue (often profound), nausea, loss of appetite, joint and muscle pain, headaches, low-grade fever, weight loss, and skin peeling that typically starts on the face. In one clinical series, lethargy was the most common symptom, affecting roughly two-thirds of patients, followed by nausea in about half.
Headaches can be particularly persistent, sometimes lasting days and ranking as the most distressing symptom for some people. Joint pain and muscle aches are usually mild but can be briefly disabling. Less common symptoms include vomiting, drops in blood pressure when standing, and electrolyte imbalances. The severity and duration vary widely depending on how long steroids were used, the dosage, and how quickly they were tapered. This is why doctors typically reduce corticosteroid doses gradually rather than stopping abruptly: a slow taper gives the body’s hormone-producing glands time to wake back up.
Corticosteroid Side Effects With Long-Term Use
Corticosteroids prescribed for chronic conditions carry their own set of body-wide effects that accumulate over time. Because these drugs suppress bone-building activity while accelerating bone loss, osteoporosis is a well-known risk of extended use. They also raise blood sugar by promoting glucose production in the liver and reducing insulin sensitivity, which can tip some patients into type 2 diabetes. Weight gain, particularly around the face and midsection, thinning skin that bruises easily, and increased susceptibility to infections round out the most common long-term concerns.
These side effects are dose-dependent and time-dependent, meaning higher doses taken for longer periods carry greater risk. For short courses of a week or two, most people tolerate corticosteroids well. The tradeoffs become harder to manage when someone needs them for months or years to control a serious condition, which is why doctors aim for the lowest effective dose whenever possible.