High hematocrit: the main side effect of Testosterone Replacement Therapy (TRT)

Testosterone replacement therapy (TRT) is one of the most effective ways to combat low testosterone levels, but it's vital that you understand the risks associated with the treatment. As with any form of hormone replacement therapy, there are a few downsides to receiving regular injections of testosterone. But do these risks outweigh the benefits? That's a decision you'll have to make for yourself!

Note: Remember the purpose of TRT: to restore testosterone to NORMAL, healthy levels in the body. Ideally, testosterone levels should be normal after TRT. Even at normal levels, there is a risk of side effects.

One of the primary risks of testosterone that is you need to be aware of is called polycythemia. This is a condition where your body produces too many red blood cells, also known as high hematocrit level. Hematocrit refers to the red blood cell content in your blood. If your hematocrit levels rise, your blood will become too thick or viscous. This can, in turn, make it more likely that you will develop strokes, heart attacks, and clotting events. Polycythemia is serious and potentially life-threatening if untreated.


What are the symptoms of high hematocrit?

In recent years, there has been an increased association between TRT and polycythemia. With TRT becoming a more mainstream treatment, more people are experiencing the symptoms of polycythemia, which include:

  • Weakness
  • Fatigue
  • Headache
  • Itching
  • redness of the skin
  • bruising
  • joint pain
  • dizziness
  • abdominal pain
  • shortness of breath
  • breathing difficulty when you lie down
  • numbness, tingling, or burning in the hands, feet, arms or legs
  • Turning very red or "flushing" after workout

When polycythemia occurs, the blood becomes very thick. But instead of being able to carry MORE oxygen, the increase of red blood cells can be dangerous. The risk of clotting increases as a result of the red blood cell count increase.

Note: While there is a risk of hematocrit increase, there is no proof that TRT increases the risk of clotting events. It's vital to be aware of the potential risk, so doctors need to be careful when prescribing TRT to men with high hematocrit levels, red blood cell disorders, and obstructive pulmonary disease. All of these things increase the risk of clotting events as a result of the hematocrit increase caused by TRT.


What are factors that increase the risks of TRT polycythemia ?

There are a number of factors that can increase your risk of developing this problem. According to Dr. Michael Scally, polycythemia "occurs quite frequently in people who are on replacement testosterone."

Age also plays a role in your polycythemia risk. Young men are far less likely to experience this problem than older men.

The mode of delivery and the dose of testosterone affect the increase in your hematocrit levels. Men who receive formulations of pharmacokinetically steady-state delivery hormones are far less likely to develop the problem than men who receive intramuscular injections of testosterone.

Topical preparations only cause the problem in up to 20% of cases. 5 to 15% of those who use testosterone patches develop polycythemia, while 10 to 20% of those using the testosterone gel develop the problem. Of course, the amount of testosterone delivered per day (50 to 100 milligrams) also affects the risk of developing polycythemia. Testosterone injections may increase hematocrit more than gels, patches, pellets, nasal or oral testosterone formulations.  Smaller injection doses given more frequently may increase hematocrit less rapidly than larger dose injections, but data are lacking to prove that fact.

Men with sleep apnea or those who smoke are at the highest risk of high hematocrit since their bodies are trying to compensate for the decreased oxygen level by producing more red blood cells.  TRT enhances that red blood cell production.


How to Lower Hematocrit?

So what can you do about the problem? Is there any way to manage it?

Those undergoing TRT must be aware that polycythemia is a real risk, as do their doctors. They must keep a close eye on their hemoglobin and hematocrit levels. If hematocrit rises above 52%, further examinations may be necessary.

Some doctors counsel reducing or stopping testosterone treatment. However, for those who are undergoing TRT as a means of restoring healthy hormone levels, this may not be an option. Some means of managing and reducing the risk of high hematocrit levels include:

  • Scaling back on the amount of testosterone gel delivered per day (50mg or less) or injection dose.
  • Changing the method of administration (using more frequent injections with smaller doses, or using a testosterone gel or cream)
  • Making sure that you are hydrated when you get your blood drawn for lab tests
  • Stopping smoking
  • Getting sleep apnea diagnosed and treated with a CPAP machine to enhance oxygen saturation levels when sleeping.

If these options do not work, a therapeutic phlebotomy (blood donation) may be the answer. Removing just one unit of blood can help to lower hematocrit by as much as 3%. For those with very high hematocrit levels, the therapy may continue for months, gradually reducing hematocrit to safe levels over time. Some physicians even prescribe regular phlebotomies (no more frequently that every 56 days is the safe frequency to avoid iron loss) as a means of preventing overly high hematocrit levels.

While phlebotomies are not covered by your insurance, they can be performed at any blood bank. Even if your insurance company won't cover the cost, you can solve the problem by donating blood (provided you are free of hepatitis, HIV, and other blood-borne infections). Experts agree that donating every 2.5 to 3 months is safe, and it's a good way to keep your hematocrit levels under control. It is important to note that hematocrit can stabilize in men on longer term TRT, so many men do not have to donate blood after a few months on TRT.

Warning: Donating more than 1 unit of blood more frequently than every 2.5 months can lower your iron and ferritin levels. This can cause fatigue. Make sure to replace the lost iron with a supplement in order to prevent anemia.

You can check your iron and ferritin with this iron blood test.

It's recommended that you donate when you are in the 51-52% hematocrit range. However, some organizations (like the Red Cross) will reject blood with a hematocrit higher than 53%, so it is good to avoid that hematocrit high level if you want to donate blood.

Hematocrit is included in the CBC and other panels:

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How to Manage Increased Hematocrit Caused by Testosterone Replacement Therapy