I took Propecia (finasteride) briefly for male pattern baldness and sometimes I wonder if it put the accelerator on issues I was already experiencing from low testosterone. (More on that below.) And I'm not alone as many men experience issues after this DHT-lowering medication. Experts estimate that between 5-20% of men that use Propecia will experience significant sexual side effects, including erectile dysfunction and lowered libido. As I discuss in my page on Propecia and Depression, long term psychological side effects are probably much more prevalent due to finasteride's negative effect on brain GABA levels. Common complaints of "Post-Finasteride Syndrome (PFS)" as it is termed includies things like brain fog, testicular/prostate pain, "lifeless" gonads (eunich-like) and low androgen hormone levels.
If you read about the experiences of those coming off of Propecia, it can be overwhelming and even discouraging. As I document in my link on The Risks of Propecia, the effects can not only affect the gonads but also the brain and can easily become a life-changing event. One can quickly lose hope. The good news is that I can say that I have seen a few things that have worked for those with PFS and I discuss those cases below:
1. Case #1. HRT (Testosterone Therapy). HRT does not always help victims of Propecia, but sometimes it works very well. From what I have read, PFS sufferers tend to have lower testosterone levels. However, it is my belief that this is not because Propecia causes low testosterone but rather because low testosterone men are very vulnerable to the negative brain effects of Propecia. The reason for that is simple: low testosterone can cause depression (and anxiety) and I show the research evidence in my page on Testosterone and Depression. Many men on the Peak Testosterone Forum can attest to the fact that HRT has greatly helped them in this area.
So clearly the last thing a low testosterone man needs is Propecia, which will likely then lower his GABA levels significantly. GABA, along with serotonin, are the "relaxing / peace-and-harmony" neurotransmitters. Low GABA levels are associated with - you guessed it - increased depression and anxiety. Therefore, one would think that restoring testosterone levels in a PFS hypogonadal man would at least partially reverse these negative psychological symptoms.
This is, in fact, exactly what I believe happened to me. On my page How I Believe Propecia Negatively Impacted My Health, I discuss how looking through my old records revealed that I started really having difficulties with my health immediately after about six months on Propecia (to supposedly halt hair loss). It took years before I finally got on testosterone therapy, but, when I did, it was a life saver for me. It was like night and day mentally and psychologically. My depression was completely gone and anxiety was lowered about 50%. My boss commented on the positive improvements and said, "I don't know what it is, but you're a lot easier to work with!"
2. Case #2 (Lifestyle + Supplements). This young man was able, over time, to almost double his testosterone to 430 ng/dl. Of course, 430 is still pretty low testosterone, but a big improvement nonetheless. He was determined not to go on HRT as he wanted to preserve his fertility and, hopefully, rebuild his HPT function. However, he felt much, much better and here is how he said he did it: 
3. Case #3 (Weights, Running, Fish + Lifestyle). This was another young man who took it for 8 years starting at age 18! He was able to largely recover in just six months by doing the following:
The important point is that it appears that hormonal adjustments and lifestyle changes can greatly reverse the negative effects of PFS. And, undboubtedly, it may take to heal as well. There is simply no reason to despair and give up hope, and, as always, I want to warn against is "just giving up". Men can assume that they have done permanent damage, when, in fact, that does not have to be the case. However, if you give up, and succumb to the stress and erectile dysfunction and then post-finasteride syndrome often likely heads into a downward spiral.
Notice also that what they did for a cure was really not that complex: a good, clean nutrient dense diet with weight lifting coupled with a few supplements that emphasize omega-3's, a multivitamin and maca. Of course, I prefer what I call Low Fat Paleo, which should be much more arterial protective based on my personal experience. Regardless, the point is that these men got off of their standard Western Diet and took control of their health. Weight lifting for those, who do not know, has several studies showing that it can boost T, something I document in my link on Testosterone and Weight Lifting. Weight lifting can also help you burn calories for 24 hours afterward and is a proven nitric oxide booster. You do have to be a little careful about Lifting Weights and Your Arteries perhaps.
Some men resort to pharmaceutical solutions that target GABA, which can be lowered by Propecia. This is not good, of course, because these can be addictive. Of course, I encourage always trying to find a natural solution even if it takes a bit more time. In the long run, it is a much safer path to travel upon.