What causes the side effects?

what exactly causes the sexual side effects of propecia? is it the rising estrogen or is it the blockage of the dht? thanks

In my experience the side effects I had from finasteride generally were caused by estrogen. There are two reasons I know of that explain the estrogenic effects. The first is that finasteride directly raises estrogen. The second is that it lowers DHT, and DHT reduces the effects of estrogen in males. So not only does finasteride give you more estrogen, but the estrogen you have gives stronger effects when it binds to estrogen receptors.

I tried fin in the past with bad side effects, and always dropped it. I began 3.5 months ago along with arimidex and it's been great so far. If anything my sex drive has improved slightly. My body composition is slightly worse, but I've also been a little lazy in the gym. The mood swings and depression I had before on finasteride are no longer an issue. I still have two side effects, but they have improved my life if anything. Alcohol has less of a relaxing effect (finasteride affects the dopamine release you usually get from alcohol), which has led me to drink less. I've also lost the extreme sense of well-being that DHT causes. I'm still happy, just less complacent. It's ultimately caused me to do a variety of productive things rather than sleeping all day just feeling happy.

These experiences won't be the same for everybody, though. In my case, my DHT was extremely high (more body hair than anybody I've ever met), so I probably still have DHT in the low-normal range. If your DHT is already normal, then perhaps you will have a greater tendency for finasteride sides. I also probably need to find a long-term replacement for arimidex. Although I'm on a low dosage (.25mg 3-4x per week), I don't think it's safe long term. Maybe aromasin will be better.

I actually think there are two or three mechanisms for the side effects.

First, the drop in DHT. This in itself may negatively affect some men. I don't believe DHT it just a "bad hormone" - far from it.

Second, the attendant rise in estrogens. This can cause further side effects; the gyno is probably the clearest example of this.

Third, the additional hormones blocked by 5a-reductaseII inhibition. In particular, blocking 5a-reductase II inhibits the conversion of progesterone into alloprogesterone and, later, alloprogenelone. This is an important chemical to have in your brain, and the reason, I think, some people suffer from "brain fog" while on finasteride.

Boondock wrote:I actually think there are two or three mechanisms for the side effects.

First, the drop in DHT. This in itself may negatively affect some men. I don't believe DHT it just a "bad hormone" - far from it.

Second, the attendant rise in estrogens. This can cause further side effects; the gyno is probably the clearest example of this.

Third, the additional hormones blocked by 5a-reductaseII inhibition. In particular, blocking 5a-reductase II inhibits the conversion of progesterone into alloprogesterone and, later, alloprogenelone. This is an important chemical to have in your brain, and the reason, I think, some people suffer from "brain fog" while on finasteride.

5a-reductase I is far more prominent in the brain, so finasteride will only have a minor effect upon these other chemicals in the brain. I believe most cases of brain fog are also a result of estrogen sides.

I had estrogen sides from fin:

inflamation of the penis
brain fog

Both i eliminated using I3C which is an aromotase inhibitor, but i really dont know the science of why it was working

I believe I3C converts estradial to 2-OHE, which is a weaker form of estrogen. I don't believe it's an aromatase inhibitor.

If you could find a study that shows otherwise I'd be very interested.