Propecia vs Avodart

[hair_tomorrow]

As a dutasteride user, I'm concerned about maintenance and long-term efficacy. Is there any evidence that this drug will give me the long-term efficacy of finasteride (if not better)?

It's always been my opinion that the gradual drop-off in effectiveness of Propecia is a result of the remaining DHT, not a growing tolerance to the drug. After that initial 1-2 year spike of regrowth, the balding process is simply continuing due to the remaining DHT - just at a much slower rate than if you weren't taking the drug.

If this is true, then Avodart will give better regrowth over a longer period of time, and the eventual drop-off will be much less steep (and later).

Which seems to give credence to the arguement that one should start out on finasteride, and then if necessary make the switch over to dutasteride.

 

[IDOASIS]

Okay, now that dutasteride is understood to inhibit a higher amount of Type II enzyme (~98%), and that finasteride only inhibits ~90% of Type II enzyme, it's clear the dutasteride will probably yield better hair growth.

As a dutasteride user, I'm concerned about maintenance and long-term efficacy. Is there any evidence that this drug will give me the long-term efficacy of finasteride (if not better)?

can be understood.

http://www.regrowth.com/hair_loss_treat ... study1.cfm

http://www.medicalnewstoday.com/medical ... ewsid=7268


Regrowth Notes: Although this study does not deal directly with hair loss, it does show that Avodart (Dutasteride 0.5mg) is well tolerated and remains effective at reducing DHT over a long period.

http://www.medscape.com/viewarticle/473587
Dual inhibition of 5-α-reductase with dutasteride provided sustained efficacy in subjects with symptomatic [BPH] treated for 48 months," write Claus G. Roehrborn, from the University of Texas Southwestern Medical Center at Dallas, and colleagues. "Near-complete, long-term suppression of dihydrotestosterone (93% at 48 months) with dutasteride did not lead to an increase in adverse events compared with that reported in the two-year period."

 

[IDOASIS]

The type II enzyme is much more "hair specific" than the type I enzyme, so I continue to believe that dutasteride's somewhat better performance over finasteride is accounted for partly (mostly?) by its more complete inhibition of the type II enzyme, and partly (a lesser portion?) by its partial activity against the type I enzyme.

Bryan

Scalp DHT measurements were also assessed for both DHT and Testosterone. Scalp DHT was decreased 27% for 0.05mg Dutasteride, similarly for Finasteride (38%) and Dutasteride 0.1mg (37%), 54% for 0.5mg, and 82% for 2.5mg Dutasteride. Rittmaster concluded that these results show that most of the DHT in the scalp comes from type 1 5-alpha reductase.

Bryan,
I hope that u have an answer about this conflict
http://www.regrowth.com/hairloss-remedy ... esults.cfm

Scalp DHT measurements were also assessed for both DHT and Testosterone. Scalp DHT was decreased 27% for 0.05mg Dutasteride, similarly for Finasteride (38%) and Dutasteride 0.1mg (37%), 54% for 0.5mg, and 82% for 2.5mg Dutasteride. Rittmaster concluded that these results show that most of the DHT in the scalp comes from type 1 5-alpha reductase.

http://www.physics.upenn.edu/facultyinf ... index.html

Take a look at Figure 4.
How the hell could it be that According to Rittmaster proscar inhibits 38% scalp DHT ,and by this research it inhibits 70% ???.

It is not possible that there is more type 1 5-alpha than 2, and finasteride blocks 70% scalp DHT.
It is not possible that finasteride inhibits more scalp DHT than Dutasteride.

 

[Bryan]

Bryan,
I hope that u have an answer about this conflict
[...]
How the hell could it be that According to Rittmaster proscar inhibits 38% scalp DHT ,and by this research it inhibits 70% ???.

I have a very simple answer to that conflict: I don't take ANY of those numbers for scalp DHT very seriously, because there is disagreement from one study to another. I don't know which one is right, and which one is wrong. Until further studies can clarify the situation, I don't pay much attention to them.

Bryan

 

[IDOASIS]

I think the reason for dutasteride's greater effectiveness against hairloss is partly (maybe mostly) its greater effectiveness than finasteride at inhibiting the type 2 enzyme (98%-99% for dutasteride, versus 90% for finasteride), and partly the more modest inhibition of the type 1 enzyme (~50% or so).

Bryan

The type II enzyme is much more "hair specific" than the type I enzyme, so I continue to believe that dutasteride's somewhat better performance over finasteride is accounted for partly (mostly?) by its more complete inhibition of the type II enzyme, and partly (a lesser portion?) by its partial activity against the type I enzyme.

Bryan

So how can u tell that dutasteride inhibits 98%-99% the type 2 and 50% type 1 :roll: ?

Rittmaster study tells otherwise:
"Rittmaster concluded that these results show that most of the DHT in the scalp comes from type 1 5-alpha reductase"

By the way ,if we can not take any of this studies we also can not conclude about the efficiency of different doses of finasteride .

 

[Bryan]

So how can u tell that dutasteride inhibits 98%-99% the type 2 and 50% type 1 :roll: ?

You know, that's a good question, and I don't remember all the details of how the docs conducted their research in that study detailing the pharmacokinetics of finasteride and dutasteride. Without digging it up an re-reading it again, I imagine that they deduced those percentages at least in part by examining the effects of individual specific inhibitors, like finasteride (for the type II enzyne) and MK386 (for the type I enzyme.

Rittmaster study tells otherwise:
"Rittmaster concluded that these results show that most of the DHT in the scalp comes from type 1 5-alpha reductase"

I don't understand what you mean. How does what Rittmaster said above conflict with what the other researchers said? Please explain. I think BOTH statements are correct.

By the way ,if we can not take any of this studies we also can not conclude about the efficiency of different doses of finasteride .

No, I won't go so far as to say that. In my opinion, the problem really only has to do with attempts to measure so-called "scalp DHT". That seems to be a difficult thing to do accurately. I have much less of a problem with measurements of serum androgens. The only time I take something with a grain or two of salt is when I read in a study that such-and-such drug lowered scalp DHT by such-and-such percentage.

Bryan

 

[IDOASIS]

You know, that's a good question, and I don't remember all the details of how the docs conducted their research in that study detailing the pharmacokinetics of finasteride and dutasteride. Without digging it up an re-reading it again, I imagine that they deduced those percentages at least in part by examining the effects of individual specific inhibitors, like finasteride (for the type II enzyne) and MK386 (for the type I enzyme.

Bryan

Can you link me?


So we have a firm information about the serum DHT ,but we dont have an idea about the scalp DHT and which is the scalp dominant type.

No, I won't go so far as to say that. In my opinion, the problem really only has to do with attempts to measure so-called "scalp DHT". That seems to be a difficult thing to do accurately. I have much less of a problem with measurements of serum androgens.

We dont care about the serum DHT,
our concern is the scalp DHT ,and if it is not accurate and way off we can not conclude about the efficiency of different doses of finasteride.
For example ,According to Rittmaster there is a slight different between 0.5 and 2.5 mg Dutasteride serum DHT,but look at the huge different between the scalp DHT (54% vs 82%).

I think that if finasteride inhibits 70% scalp DHT ,it would have been much more effective than what we have seen so far.

 

[Bryan]

Can you link me?

Here's the citation for the study which provided that dutasteride information: "A model for the turnover of dihydrotestosterone in the presence of the irreversible 5a-reductase inhibitors GI198745 and finasteride", Gisleskog et al, Clin Pharmacol Ther 1998;64: 636-47. You can find the abstract, at least, on PubMed or Medline.

So we have a firm information about the serum DHT ,but we dont have an idea about the scalp DHT and which is the scalp dominant type.

No, I think we _do_ have a fairly firm idea about the scalp dominant type, and, as I clearly stated before, I think Rittmaster was correct in what he said about that specific issue. However, I don't think that's particularly important for anything. Stop worrying so much about scalp DHT, and start worrying more about follicular DHT.

We dont care about the serum DHT, our concern is the scalp DHT...

WRONG. It is follicular DHT you should be worried about. Stop worrying so much about scalp DHT.

I think that if finasteride inhibits 70% scalp DHT ,it would have been much more effective than what we have seen so far

That's sheer speculation.

Bryan

 

[IDOASIS]

No, I think we _do_ have a fairly firm idea about the scalp dominant type, and, as I clearly stated before, I think Rittmaster was correct in what he said about that specific issue.

So what u say is that the other study is incorrect, it can not be true that the dominant scalp type is 1 and finasteride inhibits 70% scalp DHT :roll: .

Stop worrying so much about scalp DHT, and start worrying more about follicular DHT.

what is different between those two?
Does we have an information about how much follicular DHT finasteride/dutasteride inhibit?
If we dont ,scalp DHT is our main concern.

 

[IDOASIS]

I think the reason for dutasteride's greater effectiveness against hairloss is partly (maybe mostly) its greater effectiveness than finasteride at inhibiting the type 2 enzyme (98%-99% for dutasteride, versus 90% for finasteride), and partly the more modest inhibition of the type 1 enzyme (~50% or so).

Bryan

If I get it right from this link,
http://www.geocities.com/bryan50001/dutasteride4.htm

0.5 mg dutasteride inhibits 80% of 5ar-2 and 93%-94% 5ar-1

 

[Bryan]

So what u say is that the other study is incorrect, it can not be true that the dominant scalp type is 1 and finasteride inhibits 70% scalp DHT :roll: .

You have a good point there! That does seem to cast some doubt on the other study, or perhaps the claim that most DHT in the "scalp" comes from the type 1 enzyme, or both.

Stop worrying so much about scalp DHT, and start worrying more about follicular DHT.

what is different between those two?

The scalp would include other tissues besides just the ones that produce the hair shaft. For example, it would also include the sebaceous glands (which are rich in 5a-reductase type 1) and the sweat glands. But those sections have no apparent connection with the dermal papilla which controls the production of the hair shaft.

Does we have an information about how much follicular DHT finasteride/dutasteride inhibit?

Not to my knowledge.

If we dont ,scalp DHT is our main concern.

Just because we don't have any solid data for the actual hair follicle, that doesn't mean we should concern ourselves with something considerably less precise ("scalp DHT"). I suggest that you just use measurements of serum DHT as a rough guide. Forget the "scalp".

Bryan

 

[Bryan]

If I get it right from this link,
http://www.geocities.com/bryan50001/dutasteride4.htm

0.5 mg dutasteride inhibits 80% of 5ar-2 and 93%-94% 5ar-1

You're mis-reading that graph. I can't really blame you for that , because it IS rather difficult to understand! :wink:

It shows that 0.5 mg/day of dutasteride does indeed inhibit the type 2 enzyme almost completly, leaving behind only a tiny sliver of around 1% or so. It's almost impossible to explain that graph using just words in a reasonable amount of time, so I'll just advise you to go back and take another look at it. Study it VERY carefully.

Bryan

 

[IDOASIS]

Just because we don't have any solid data for the actual hair follicle, that doesn't mean we should concern ourselves with something considerably less precise ("scalp DHT"). I suggest that you just use measurements of serum DHT as a rough guide. Forget the "scalp".

Bryan

How can I forget the scalp DHT it seems to have a direct conection to haircount.

At 24 weeks hair counts were:


95.5 for Avodart 0.5 mg/day,

109.8 for Avodart 2.5 mg/day.

There is a slight different at the serum DHT (93% Vs95%), it is not much different to indicate that range of haircount .
It is simply not enough
On the other hand ,
0.5 mg dutasteride inhibits 54% scalp DHT
2.5 mg inhibits 82%.
Now thats a different to justify that range of haircount.
Dont forget that those results are at 6 months, the different between the doses would increase by time.

Just because we don't have any solid data for the actual hair follicle, that doesn't mean we should concern ourselves with something considerably less precise ("scalp DHT").
Bryan

I think it is more relevant than serum DHT, I don't think that they have measured it for nothing.

 

[IDOASIS]

It shows that 0.5 mg/day of dutasteride does indeed inhibit the type 2 enzyme almost completly, leaving behind only a tiny sliver of around 1% or so.

Bryan

Please try to explain it to me, I just don't see it.

 

[Peter2]

I am now more than 3 years on dutasteride (Avodart), .5 mg dutasteride per day and I have not only maintained my existing hairs, I had regrowed the last 2 years alot of new hairs all around my head, the shorter and weaker hairs has growing thicker and healtier. The last 6 months, I use the tricomin and now they are growing new hairs on my old bald, not anymore existing teenage hair line (I am a Norwood 1.5-2 thanks dutasteride . The hairs are very short, but some of theme they have pigmentation, and growing darker and longer, I believe 4 or 5 millimeters long. Maybe some day, I go back to a Norwood 1, I hope.

 

[techprof]

peter2, good to know your success. what was your Norwood before starting dutasteride? do you have pictures? can you post them in the success stories.

 

[Aplunk1]

Whoot!

Alright, Peter!

Good news, man. I'm glad you posted.

Hurray for the successful Avodart users!

 

[Aplunk1]

I think it's weird how in the FDA Phase II studies for Avodart's dutasteride only involved 416 men with Norwood's IIIv, IV, and V.

Why not study the effects of dutasteride on someone in the beginning stages of baldness, like Norwood I or II?

 

[techprof]

aplunk, NW2s will not take the risk with dutasteride. They will use finasteride only. Only if they recede to NW3, they are going to take their chances.
(I know that you are doing well with dutasteride, good luck).

 

[Jacky81]

I am Norwood 1 - Norwood 2 (more 2 i think) and i take dutasteride because with finasteride after 4.5 years my front thinned out.