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Finasteride Half-Life

Discussion in 'Antiandrogens - Propecia, Dutasteride, etc.' started by thiningattop, Feb 15, 2006.

  1. thiningattop

    thiningattop Member

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    I read that Finasteride has a half-life of anywhere between 4 - 7 hours. Considering that a day is 24 hours long, that doesnt seem too good. Would cutting a pill in half and taking 0.5mg in the morning, then 0.5 at night be effective?

    What are your opinions?

    Currently right now im taking 0.5mg at night only.
     
  2. Aplunk1

    Aplunk1 Senior Member

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    It's much better just to take the 1mg recommended dose for hair maintenance and regrowth. However, I see no harm in splitting the dosage throughout the day.

    Whatever you do, don't up the dosage to more than 1mg.
     
  3. thiningattop

    thiningattop Member

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    Im thinking of changing my dose to 0.5mg twice a day.

    Why do u think 1mg once a day is better?

    I just want to hear peoples opinions before i start changing my doses around.
     
  4. Anderz

    Anderz Junior Member

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    I've thought about that too. It seems logical to split the dose.
     
  5. Fallout Boy

    Fallout Boy Experienced Member

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    Why is that?

    Some people take a little more if they cut the proscar into 4 pieces instead of 5.
     
  6. cook'n'milkies

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    I dont see a big problem, I'm going to start taking 1mg in the morning a 1 mg at night. I know i risk side effects but it's worth the risk to me. As long as i don't get bitch tits and I can still make whoopie with my gf i'm cool.
     
  7. Bryan

    Bryan Senior Member

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    Why do you say that? I would consider the reasonable maximum dose of finasteride to be somewhere in the range of 10 mg to 20 mg per day.

    Bryan
     
  8. Bryan

    Bryan Senior Member

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    Here's a question for you: considering the fact that the half-life of finasteride is somewhere around 4 - 7 hours, why do you suppose it takes a week or two for DHT levels to get completely back to "normal" after the last dose of finasteride? Think about that, and post your answer here...

    Bryan
     
  9. Fallout Boy

    Fallout Boy Experienced Member

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    There was a period of 1 week where I ran out of Propecia...so when I got more pills I took 1.5 mg of Propecia for about a week thinking it might be better because I missed a week.

    Do you think it makes a difference that I upped the dosage .5 for a week?? or was it the wrong thing to do? Just curious ..I'm now back to 1 mg a day
     
  10. Bryan

    Bryan Senior Member

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    I doubt that it made any significant difference.
     
  11. thiningattop

    thiningattop Member

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    I didnt know that.
    I just heard that once you stop taking it, the next day your levels should be back to normal. Which is why some people stop noticing side effects the day after they quit the drug.

    Where did you get that information from? Is there anywhere i can read up more on it. Cause if thats true ... then maybe taking 0.5mg twice a day would be pointless, since DHT wont go back to normal after only 7 hours.

    Thanks
     
  12. Bryan

    Bryan Senior Member

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    Oh, merciful heavens! You must be a relative newbie around here! :) Yeah, it takes several days for DHT levels to slowly "recover" after you stop taking finasteride (even much longer for dutasteride). Check out this graph, which I've posted on several hairloss sites and has been downloaded almost 3,000 times over the years:

    http://www.geocities.com/bryan50001/graph8.htm

    It shows serum DHT levels for up to 7 days after various SINGLE doses of oral finasteride. Keep in mind that if you've been taking finasteride every day for a long period of time and then you suddenly quit, your DHT levels would be even a little lower than what that graph shows, and consequently would take even a little longer to get back up to "normal".

    That graph was included in a study on finasteride published in a urology medical journal. There are other studies which have published similar information, so there's absolutely no doubt whatsoever as to the fact that DHT levels only slowly "regenerate" after the last dose of finasteride.

    Yes. That was exactly the point I was trying to make. I had assumed that you were already familiar with the properties of finasteride, and the details of how testosterone gets converted to DHT.

    Bryan
     
  13. techprof

    techprof Experienced Member

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    Bryan do you expect a linear relationship between the plasma DHT and scalp DHT?
    In otherwords though plasma DHT takes time to recover, the scalp DHT goes back to normal levels after 7 hours (half life)?
     
  14. Bryan

    Bryan Senior Member

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    I have no reason whatsoever not to assume that the relationship is linear.

    Bryan
     
  15. techprof

    techprof Experienced Member

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    bryan, I got this from the hairsite discussion on dut.

    OPTIMAL DOSAGE FOR HAIR LOSS
    For the treatment of BPH, the official recommendation from GSK is to take 1 x 0.5mg capsule orally every day with or without food.

    However, it appears that for treating hair loss, a daily dose of 2.5mg daily seems to generate the best results. See Dutasteride Results.

    Also, please follow this thread in Dutasteride Forum which discussed the effect of Avodart on serum DHT vs scalp DHT.

    0.5mg Dutasteride inhibits ~ 92% serum DHT and 55% scalp DHT
    2.5mg Dutasteride inhibits ~ 95% serum DHT and 82% scalp DHT

    why is scalp dht not linear related with serum dht for dut?
     
  16. Bryan

    Bryan Senior Member

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    I'll just mention again what I've said several times before on various hairloss sites: I think those numbers are pretty meaningless, because they've been contradicted by another study which was done by a whole bunch of big-name dermatologists; while they only used finasteride in this other study (not dutasteride), they found a good linearity between serum and scalp DHT.

    Bryan
     
  17. techprof

    techprof Experienced Member

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    thanks Bryan. So for now the more we kill dht in the serum, we will have proportionally have less dht in the scalp. That makes sense.
     

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