Overall I have had a very good experience with HRT (Testosterone Therapy) and it has been a real life changer for me. If you’re interested, you can read the details in My Personal Health Story page. However, not everyone has a great experience on HRT and below I discuss some of the reasons why. As you will see, most of the issues are preventable, which is why I wrote this page. HRT gone bad can be quite stressful and disappointing for a man that wants to get back on this feet again and has been promised by some commercial or advertisement that it would be a quick and easy fix. So please check these out and ask any questions you have on the Peak Testosterone Forum.
1. Elevated Estradiol. TRT (Testosterone Replacement Therapy) is actually a misnomer in my opinion, because it implies that testosterone is the only hormone that needs to be worked with. This is simply not the case and the reason is that, as you increase testosterone, some of it will aromatize, via aromatase, into estradiol. It is very common, for example, for a man to experience some nice benefits from testosterone for a couple of weeks and then the effect fades.
One of our forum posters (PRSArtist) is the perfect example of this. Look how he describes what HRT did for him in the first two weeks of treatment:
“1st thing I “noticed” were morning erections (that’s every morning!) after about 2 weeks of treatment. Didn’t think too much about that. After 4 weeks my sex drive is “Thru the roof” Wasn’t ready for it to hit me this hard! Like some guys on here, my low T ruined past relationships to the point where I’ve had no interest in sex for the past 5 years so I have no outlet for these urges! And had to ” take matters into my own hands”! Now I think about sex all the time!!! All day, every day! (multiple times a day!) This may be a little much??” 
Some people call this the “honeymood period.” Some guys notice miraculous results during these first couple of weeks. But notice how quickly it turns south just two weeks later:
“I’m concerned because erections are absolutely impossible now, and that the only thing I could think of? Sex drive is back, this is NOT a good combination To live with for a month. I’m more than a little concerned.”
Bascially, his libido was still high, but he had rather extreme erectile dysfunction. Sure enough his estradiol was very high – 58 pg/ml! From what I’ve seen, most HRT clinics try to keep a man somewhere between 20 and about 35, which is a youthful level. So this man’s readings were about double. His doctor helped him pull it down with an aromatase inhibitor and then he wrote:
“This post scares the crap outta me! E2 of 78 should not be passed over! Everyone is different, but I could NOT get an erection with My E2 levels above 30! I had struggled with this for the past 6 months, and I’m on a pretty high Dose of arimidex .75mg EOD. If your noticing lack of morning wood, and your continuing the same treatment dose and schedule? That # will only get higher. Sooner or later your lack of morning wood Could turn into “lack of ANY wood”! Even my Dr. Would treat an E2 level of 78! This really isn’t OK to be that high!” 
Guys often retain water and have gyno when levels get this high as well.
Now you may wondering, “What does low estradiol have to do with HRT?” That’s a good question. In general, as you raise a man’s plasma testosterone levels via HRT, some of it will be converted to estradiol. In fact, if you push a man’s total testosterone up over about 800 ng/dl, there is a good chance that he will end with high estradiol. So why am I worried low estradiol then? The answer lies in the fact that some HRT clinics manage elevated estradiol with Arimidex (anastrazole). It’s cheap and well-tolerated with short term side effects. (It can effect the clotting cascade in some men.)
Quite a few men are very sensitive to Arimidex and their estradiol ends up getting slammed down too low. You’ll hear guys on The Forum talk about an “estrogen crash” when this happens and it’s not fun. It can take several weeks to pull out of it and often has accompany erectile and libido issues.
NOTE: Savvy physicians have ways around the Arimidex issue, including compounded and liquid anastrazole.
3. Low SHBG. Men with low SHBG often have accompanying (concomitant) insulin and liver (NAFLD) issues. And the problem with low SHBG is that the hormones are just cleared out very rapidly from the blood when a man is given testosterone therapy. For example, the typical guy given an intramuscular injection of cypionate will peak 3 or 4 days later. However, a low SHBG male will peak on the first or second day and will have the testosterone clear out of his system rapidly. This rapid rise and fall of both testosterone and estradiol make HRT problematic and difficult for men with this condition.
From what I have seen, these men have to do a lot of experimentation before they find a protocol that helps them to feel better. Proprionate and topicals seem like they work best for this population but only after a fair amount of protocol failures. Researchers are still trying to find practical solutions for these guys and patience is an absolute must when beginning standard testosterone therapy.
4. A Rise in PSA. This is one I know about first hand. My PSA reads post-HRT had always been less than 1.5. (Ideally, your PSA is below 1.0.) My HRT clinic pulls my PSA number regularly and in late 2013 the lab reported a value of 6.3! I abstained from you-know-what and exercise and repulled the number a week later and it had only gone down to 5.0. And, to my horror, my clinic dropped me from HRT the next day. At that point, I had just become a big legal liability and was out the door until I got my urological clearance to go back on HRT.
I found that my HRT levels dropped rapidly, the details of which are outlined on my page entitled My High PSA But No Cancer. I had always had testosterone levels prior to testosterone therapy in the low to mid 300’s. However, one month after going off of HRT, my levels were 121! This is because there is a “rebound effect” after being on HRT with your natural production partially shut down. When you go off of HRT, it takes a few months for your own natural baselines levels of T production to resume. Obviously, this can be a very unpleasant problem for men on HRT who have to suddently quit due to prostate issues.
BPH, prostatitis and inflammation can all dramatically raise PSA and so it seems a tad unfair to suddenly pull a man off of HRT. However, it is the clinic’s only way to force a man to talk to a urologist and get a biopsy if necessary. I was able to get back on testosterone about a month after stopping. However, I was lucky. What if I had had some PIN (precancerous) cells? What if I had had prostatitis and needed months of antibiotic treatments? How one handles these situations depends on the urologist and this is not in the fine print when you sign up for T therapy.
5. A Rise in Hematocrit. Another common problem that can occur with HRT is an increase in red blood cells. Testosterone stimulates a kidney hormone called erythropoietin (EPO) that increases red blood cell counts and, therefore, hematocrit and hemoglobin. If these values get high enough and out of range, you will probably have to donate blood or lower your testosterone dose. Again, this is a problem that can occur that not many men know about when they go on HRT. Usually, from what I have seen, men can donate blood regularly and pull their hematocrit/hemoglobin back in range. And it is critical to do so, because high hematocrit/hemogolobin can increase the risk of stroke as I discuss in my page on Ways to Lower Hemoglobin.
There is also the risk of having to go off of HRT altogether and we had one poor guy who had to do just that. You can feel the stress in some of the member’s posts:
“This one makes me a little bit nervous. Red blood cells 6.18 Hemoglobin 18.5 Hematocrit 55.5 Two months ago I gave blood and started drinking more water I read that helps to get it down. I told my doctor about this. So were keeping an eye on this in about three months I will have a another blood test will make sure what to do.” 
“Last blood work had hemoglobin at 17, and now 18 and that is just too high. Does anyone have any links or info on the hemoglobin being so high? they said T therapy can raise it as well. The super low E2 score tells me something as well. progress, but still.. PS: I gave blood about 6 months ago and swore I would never do it again as I almost pass out when I do. Damn. I would rather self-inject than donate blood.” 
Again, one can lower their testosterone, but this would be considered a big problem for most men.
NOTE: There are also certain out and outright potential dangers for some subpopulations of men and I discuss those in my link on The Risks of HRT.
Again, most of the above problems of HRT can be overcome by the following:
b) Careful monitoring of estradiol and conservative prescription of any aromatase inhibitors.
c) Losing weight and getting your abs back. Lowering your weight will decrease your need for an aromatase inhibitor. Weight gain is a risk factor for Metabolic Syndrome and diabetes, both of which will increase your likelihood for a PSA-increasing prostate enlargement.
Please discuss with your doctor any concerns.