Why Are BPH Patients Prescribed 5mg Finasteride if 1mg Suppresses the Same Amount of DHT?

I’m considering upping my dose of finasteride. When I began taking it 18 years ago I took the full 5mg daily. About 6 years ago I started taking 1mg Propecia, and I feel it has not maintained my hair as well.

Now, I’ve read the argument, and seen the graph explaining that finasteride suppresses DHT at a rate that platoes at about ~70% DHT for 1mg to 5mg. So the suppression rate of DHT is no better for 5mg of finasteride than for 1 mg. My question is this, if the amount of DHT suppressed by 1mg – 5mg finasterde is virtually the same, why BPH patients proscribed 5mg instead of 1 mg? If purpose of the medication is to reduce the amount of DHT wouldn’t 1 mg be as effective in the treatment of BPH, if dosages of 1mg – 5mg produce the same effect on DHT concentration?

For this reason I’m skeptical of doctors who say that increasing my dose of finasteride won’t produce better results (as I believe I’ve had before). Can you tell me where my reasoning is wrong?

Thanks a lot.

Block Quote

When drug doses are assessed, they are tested against large, statistically valid populations who have symptoms. The effectiveness of a drug is determined by balancing the safety of the drug.

In the case of finasteride, huge populations of balding men were given graded doses from as small as 0.25mg to as large as 5mg, and the researchers looked for what dose produced the best response with the least side effects.

For balding, although the drug worked well in ranges of 1-5mg, the 1mg dose produced essentially the same results as the 5mg dose with the least side effect. The same approach was done for those with benign prostatic hyperplasia (BPH) and the conclusions were that the 5mg dose was the most effective dose for that disease.

Tags: finasteride, propecia, proscar, hairloss, hair loss, dosage

2 thoughts on “Why Are BPH Patients Prescribed 5mg Finasteride if 1mg Suppresses the Same Amount of DHT?

  1. Balding is a complicated process, with more than just DHT involved. Does 5mg of finasteride lower DHT levels more than 1mg does? Yes, absolutely (although studies show not much, aka a non-linear dose/response curve).

    The slight boost to DHT lowering ability from the higher dose seems to make virtually no difference in halting MPB, but apparently does make a difference in BPH.

  2. merck Tested up to 80mg of finasteride and they said it lowered DHT to the same levels as 1mg.

    “DR. WALDSTRAICHER: Let me just share some experience that we’ve had with finasteride, which is the Type II inhibitor, obviously, that we’re discussing today. Over the years, we have gone up to very high doses of finasteride for the development of Proscar, our 5-milligram dose. Even up to 80 milligrams of finasteride, you don’t actually get more than about the same 70 percent suppression in DHT that you get with even lower doses of finasteride.”



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