Most people think steroids and the first thing that comes to mind is muscle. That’s the general association. But there’s another effect that doesn’t get much talk, and it weighs just as much. Steroids change the amount of red blood cells your body makes pretty drastically. That is actually the point for some medical diseases. That’s why doctors prescribe them in the first place. But when someone takes steroids outside of medical supervision, that same effect can quietly push red blood cell count into dangerous territory. Most people don’t realise until they start how important it is to know what’s happening inside your body.
What Red Blood Cells Do and Why Count Matters
Red blood cells have one main job. They carry oxygen from your lungs to your muscles, organs, and tissues. They also carry carbon dioxide back out.
More red blood cells means more oxygen delivery. That is why athletes care about this number. Better oxygen supply translates to better endurance, faster recovery, and more output during training.
The normal range for adult men is roughly 4.5 to 5.9 million cells per microlitre of blood. For women it sits between 4.1 and 5.1 million. These numbers exist for a reason. Go too far below them and you feel exhausted all the time. Go too far above them and the blood starts causing its own problems.
How do steroids actually raise the count?
Anabolic steroids are synthetic versions of testosterone. When they enter the body, red blood cell production goes up through two separate pathways.
The first is through a hormone called erythropoietin, or EPO. This hormone is made by the kidneys, and it signals the bone marrow to produce more red blood cells. Higher testosterone levels push the kidneys to release more EPO than normal. More EPO means more red blood cells being made.
The second pathway is more direct. Testosterone receptors exist in the bone marrow itself. When steroid levels rise, these receptors respond and production speeds up without needing EPO as a go-between.
Both pathways running at the same time are why steroid users can see their red blood cell count climb so significantly, especially with heavy or long-term use.
When Raising Red Blood Cell Count Is the Goal
This effect is not always unwanted. In medicine, it is sometimes exactly what is needed.
Anaemia is probably the most well-known example. When the body does not produce enough red blood cells, fatigue and weakness follow. Anabolic steroids have been used for decades to stimulate production and bring counts back to a functional level.
Aplastic anaemia is a more serious version of this. The bone marrow stops making enough blood cells altogether. Steroids help kick it back into action and have been part of treatment for this condition for a long time.
Patients going through chemotherapy often develop anaemia because cancer treatment damages bone marrow. Steroids can help restore some of that lost production during recovery.
Hypogonadism, where the body does not produce enough natural testosterone, also comes with lower red blood cell counts as a side effect. Testosterone replacement brings the numbers back to where they should be, and that includes red blood cell levels.
In all of these situations, the increase is monitored, controlled, and happening under medical care. That changes everything.
What Happens When the Count Goes Too High
Too many red blood cells lead to a condition called ‘polycythaemia’. This is where the risks become real and serious.
Blood is not just red blood cells. It also contains liquid plasma. When the red blood ceincreasesroportion gets too high, the blood physically thickens. It moves more slowly through vessels. It clots more easily. And that is when things can go wrong quickly.
Blood clots are the biggest concern. A clot in a deep vein is painful and dangerous. If a clot breaks loose and travels to the lungs, it becomes a pulmonary embolism. If it reaches the brain, it causes a stroke. If it blocks blood flow to the heart, it triggers a heart attack. These are not rare edge cases. They are documented outcomes of unmonitored steroid use.
High blood pressure often develops alongside elevated red blood cell count. Thicker blood needs more force to move through the body, and the heart bears that extra load.
Early signs of too many red blood cells include persistent headaches, dizziness, blurred vision, and a flushed or reddish appearance in the face. Many people ignore these symptoms or attribute them to other causes, which is part of what makes this risk easy to miss until it becomes serious.
Hematocrit: The Number That Tells You the Most
Haematocrit is the percentage of your blood volume that is made up of red blood cells. For men the healthy range is 38 to 52 per cent. For women, it is 35 to 47 per cent.
Steroid users commonly see their haematocrit climb above 52 per cent. Once it crosses 54 or 55 per cent, the risk of clotting increases meaningfully. Above 60 per cent, it becomes a medical emergency.
This number can rise slowly and silently. No dramatic symptoms, no obvious warning. It is just a gradual thickening of the blood until something gives way. Regular testing is the only way to catch it before that happens.
Who Is Most at Risk?
Not every steroid user will develop dangerously high red blood cell counts. But some people are more vulnerable than others.
Heavy, long-term users face the greatest risk. The more you use it and the longer you use it, the stronger the effect on red blood cell production tends to be.
Men are more affected than women because testosterone stimulates red blood cell production more strongly in male physiology to begin with.
People who smoke, live at high altitude, or already have cardiovascular issues start from a higher baseline. Adding steroids to that picture raises the risk further.
How to Manage Red Blood Cell Count?
If steroids are used under medical supervision, a doctor will regularly monitor blood markers. But there are practical things that help manage this condition regardless.
Regular blood tests are the most important step. Checking haemoglobin and haematocrit every few months catches problems early before they become emergencies.
Staying hydrated matters more than most people think. Dehydration alone thickens the blood. Combine it with elevated red blood cells, and the risk multiplies. Drinking enough water daily is one of the simplest things that genuinely helps.
Therapeutic phlebotomy is a medical procedure where a controlled amount of blood is removed to bring red blood cell concentration down. It sounds intense, but it is a routine, safe procedure used regularly in this context.
Adjusting the dose is another option when haematocrit climbs too high. Lowering steroid intake reduces the stimulus for excess production. Such changes should always be discussed with a doctor rather than done alone.
Conclusion
Steroids and red blood cell count have a real, well-documented relationship. In the right medical setting, that relationship is useful and sometimes necessary. Outside of it, the same effect becomes a quiet risk that builds over time without obvious warning. The blood thickens, clots become more likely, and the consequences can be severe. Regular monitoring, honest conversations with a doctor, and paying attention to early symptoms are not overcautions. They are the difference between using steroids safely and discovering the consequences of not doing so.
