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Dutasteride: much more hair than finasteride in tests: Stats from study


#1

Results
In this phase II, dose-ranging study, 2.5-mg dutasteride was superior to 5-mg finasteride in improving scalp hair growth in men between ages 21 and 45 years with MPHL as judged by target area hair counts, expert panel assessment, and investigator assessment at 12 and 24 weeks.

In a test area at 24 weeks, results showed:
Placebo −32.3 hairs
Finasteride 5mg 75.6 hairs
Dutasteride 0.1 mg 78.5 hairs
Dutasteride 0.5 mg 94.6 hairs
Dutasteride 2.5 mg 109.6 hairs

Dutasteride 2.5mg vs. 0.5mg
The 2.5-mg dutasteride dose was consistently superior to 0.5-mg dutasteride in promoting scalp hair growth. The 2.5-mg dose was also better than the 0.5-mg dose at suppressing scalp DHT (79% vs. 51%), whereas it was only marginally better at suppressing serum DHT (96% vs. 92%). This difference in the dose-response of serum and scalp DHT to inhibition with dutasteride is likely to be due to the greater contribution of type 1 5α-reductase to scalp DHT concentrations.

Finasteride 5mg vs. Dutasteride 0.1mg
5 mg finasteride suppressed scalp DHT to a similar degree as 0.1 mg dutasteride group (41% and 32%, respectively). Many of the clinical effects (hair count changes, global panel assessment, and investigator assessment) were also similar in these two groups, supporting the similarity in scalp suppression between 5-mg finasteride and 0.1-mg dutasteride.

Adverse Effects
Both dutasteride and finasteride were well tolerated in this phase II study, and no new safety concerns have arisen in any of the phase II and phase III studies of dutasteride given at doses up to 5 mg daily (the 5-mg dose was used in a phase II study for BPH).

There were no significant differences in side effects, serious adverse events, or withdrawals due to adverse events among any of the treatment groups, including placebo. In total, 11 subjects withdrew because of adverse events: 3 were in the placebo group (irritable bowel syndrome and impotency), 7 in the dutasteride 0.1 mg group (decreased libido, malaise and fatigue, mood disorders, skin disorders, injuries caused by trauma, and gastrointestinal- and neurology-related complaints) and 1 in the dutasteride 0.5 mg group (gastrointestinal discomfort and pain).

Decreased libido was noted in:
2 subjects in the placebo group
2 subjects in each of the 0.05-mg and 0.1-mg dutasteride groups
1 subject in the 0.5-mg dutasteride group
9 subjects in the 2.5 mg dutasteride group
3 subjects in the finasteride group

Of the 9 subjects with decreased libido in the 2.5-mg dutasteride group:
4 resolved while receiving therapy
1 resolved within 3 weeks
1 resolved within 8 weeks of stopping drug therapy
1 subject, decreased libido continued after therapy had been stopped and was presumed by the subject to be unrelated to the trial or drug therapy

Concerning possible sexual adverse events, there was no evidence in the present study that either dutasteride or finasteride was associated with impotence. However, 9 men in the 2.5-mg dutasteride group complained of decreased libido, compared with 1 man in the 0.5-mg dutasteride group and 3 men in the finasteride group. As with previous studies with finasteride, this adverse event was characterized as either mild or moderate in severity and often resolved with continuation of the medication. In the 4-year follow-up of the phase III trials in BPH, dutasteride (0.5 mg) was well tolerated and the incidence of the most common sexual adverse events was low and tended to decrease over time.

The only subject to develop gynecomastia was in the placebo group.

Duration of Effects
The serum half-life of finasteride is 6 to 8 hours. Dutasteride has a serum half-life of approximately 4 weeks, and this long half-life was evident in the persistent suppression of DHT with the 0.5-mg and 2.5-mg doses after dutasteride treatment was stopped. Because of this long half-life, men being treated with dutasteride should not donate blood until at least 6 months past their last dose to prevent administration to a pregnant female transfusion recipient.


#2

2.5 mgs a day of dutasteride gave patients a 109 hair increase in tested area vs. a 32 hair loss with placebo.

Finas at 5 mgs only increased haircounts by something like 74 hairs.

I think one mg of finas in the morning and one at night (2 mgs) would be much more effective than 5mgs of it all at once because of the half life. In fact, it would probably be much closer to dutasteride, especially if you drank some grapefruit juice and slowed its metabolization.


#3

» I’m planning on starting a regimen soon. Benji, do you believe it would be better and safer to go with the finasteride 2x a day than the 2.5 dutasteride? Also, do you take any natural supplements in your regimen?


#4

It’s not really logical just to compare the absolute haircount increase from one drug to the absolute haircount increase from another drug. You need to compare the haircounts relative to placebo.

Finasteride had a haircount increase of +73.2, compared to a loss of -29.6 with the placebo. That’s a net difference of +102.8 for finasteride.

Dutasteride at the approved dosage of 0.5 mg/day had a haircount increase of +95.5, compared to a loss of -29.6 with the placebo. That’s a net difference of +125.1 for Avodart.

Therefore, Avodart was 125.1 / 102.8 = 21.7% more effective than Proscar at fighting MPB in this trial, in a more fundamentally intuitive sense.

Using this same proper methodology, 2.5 mg/day of dutasteride (which I certainly wouldn’t recommend taking, because it’s far above the approved dose) was 139.5 / 102.8 = 35.7% more effective than Proscar.


#5

Good stuff Bryan…

Bryan,

I think that taking 1.0 mgs of finasteride in the morning, and 1.0 mgs in the evening (especially if one drinks some grapefruit juice which inhibits the enzyme that metabolizes finasteride) might be able to up finasteride’s performance to around dutasteride territory for the .5 mg dose. Just an opinion. If finas could just extend its half-life to 24 hours in some way…it would probably improve to near dutasteride-effectiveness.

Like you…I think dutasteride’s more complete inhbition of type two alpha five is why its better. I dont think type one plays much of a role, or the variance in outcome would be bigger.


#6

Benji

This taking Fin twice a day plan seems like a new theory for you; Ive never seen you mention it before.

Let me ask you this: Once ONE dose of Finasteride is taken, isn’t the half-life of the drug then irrelevant? Isn’t it the 5ar enzyme that stays suppressed for a long period of time, hence the reason some people have success with intermittent use?

Also, in regards to the grapefruit juice, I think one must be careful if one is taking OTHER prescription meds that they might not want ‘lingering around’ for longer periods of time.

Still, I find your idea intriguing (of course taking 1.25 mg of Proscar twice a day would be much cheaper than 1 mg of Propecia) and I have read a few testimonials in the past from users who have tried this approach and had success after years of a daily dose had started to lose effectiveness.


#7

braskie…I used to take a vitamin packet daily that had some lysine, arginine, saw palmetto, green tea, and biotin in its ingredient lists. I drink some tea…Im pretty lazy though in this regard. Its been either finas or dutas + nizoral twice a week for years. Ive used prox-n for months at a time, ran out, and waited a few more months before getting another 120 ounces of it. I think all three have been beneficial…the prox-n certainly made the hair darker

jwm…the adult half life of finas is 6 hours. That means that every six hours there is only about half as much of it in your blood. Meaning that after about 18 hours, you wouldn’t have a whole lot. If you drank some grapefruit juice which inhibits CY34A (or whatever that enzyme is correctly named), it should be metabolized much slower. If you took a divided dose (maybe even .5 mgs as the dose response curve with finas is kind of flat with their not being a great big difference between .2 mgs and 1 mg…and 1mg and 5 mgs), the level of supression of alpha five type two might be pretty high at all times (this is assuming you dosed every 12 hours).

Bryan has mentioned in the past that dutasteride’s apparent better effectiveness than finasteride (21.7% more effective at .5% dutas vs. 5mgs of finas) is probably due to dutaseride’s BETTER suppression of type 2 alpha five reductase and NOT its 51% supression of type 1 alpha five reductase. Dutasteride has something like a four week half life or whatever. It stays in the body a long time. If we could get finasteride’s half life to be longer, it might be able to come very close to matching dutasteride’s effectiveness without effective type one alpha five reductase, which is located in the sebaceous glands, sweat glands, and your brain. Plus it would be cheaper and probably have less side effects. I wanted to know if Bryan was thinking along the same lines here.


#8

» Bryan,
»
» I think that taking 1.0 mgs of finasteride in the morning, and 1.0 mgs in
» the evening (especially if one drinks some grapefruit juice which inhibits
» the enzyme that metabolizes finasteride) might be able to up finasteride’s
» performance to around dutasteride territory for the .5 mg dose.

Yeah, I’ve thought a lot about that in the past, and posted about it a few times. However, my gut feeling is that it would take a lot more than just 1 mg of finasteride twice a day to achieve dutasteride-like levels of inhibition. I think something along the lines of a Proscar tablet (5 mg) four times a day (evenly spaced throughout the day) would get you closer to that goal. It would be absolutely fascinating to see an actual clinical study which measured how much finasteride (and taken how often) would be required to actually achieve dutasteride-like effects.

» Like you…I think dutasteride’s more complete inhbition of
» type two alpha five is why its better. I dont think type one plays much of
» a role, or the variance in outcome would be bigger.

Well, it seems logical that the type 1 enzyme must play at least some minor role, since even just the standard dutasteride dose of 0.5 mg/day inhibits the type 2 enzyme by around 98%-99% (according to Gisleskog et al). It’s kinda hard to believe that further reducing that remaining 1%-2% with 2.5 mg/day of dutasteride would provide any noticeable improvement of haircounts. But all of this is highly speculative! :stuck_out_tongue:


#9

The thing is, not many people are going to risk taking 2.5 mgs of Dut a day. Most take the standard 0.5 mg and even less. 0.1 mg was comparable to 5 mg of Fin which, for safety reasons, stands to reason that most would simply take 5 mg of Fin instead of the ‘risky’ Dut.


#10

» The thing is, not many people are going to risk taking 2.5 mgs
» of Dut a day. Most take the standard 0.5 mg and even less.

Sure, but I said all that in my previous post just for illustrative purposes!

If the 5a-reductase type I enzyme has no effect at all on MPB, then why would 2.5 mg/day of dutasteride have any more of an effect than only 0.5 mg/day, which already inhibits the type II enzyme by around 98%-99%? :slight_smile:


#11

» » The thing is, not many people are going to risk taking 2.5 mgs
» » of Dut a day. Most take the standard 0.5 mg and even less.
»
» Sure, but I said all that in my previous post just for illustrative
» purposes!
»
» If the 5a-reductase type I enzyme has no effect at all on MPB, then why
» would 2.5 mg/day of dutasteride have any more of an effect than only 0.5
» mg/day, which already inhibits the type II enzyme by around 98%-99%? :slight_smile:

0.5mg does not inhibit 98-99%


#12

» 0.5mg does not inhibit 98-99%

And you base that claim on WHAT, exactly? :slight_smile:


#13

» 0.5mg does not inhibit 98-99%

Take a look at this set of graphs from the Gisleskog et al studies on finasteride and dutasteride:

Scroll down slightly to graph C of Figure 6, and you can see the levels of inhibition of the 5a-reductase type II enzyme for the doses of 0.1 mg/day, 1 mg/day, and 10 mg/day of dutasteride. Since there is no data for the specific dose of 0.5 mg/day (Avodart), you’ll have to do a little extrapolating (I suppose “interpolating” would be a better word) between the 0.1 and 1.0 lines to get an approximation. Since 1.0 mg/day clearly provides 99%+ inhibition after only 28 days, my estimation is that 0.5 mg/day probably provides 98% to 99% inhibition of the type II enzyme, once it reaches steady-state levels in the body.


#14

impressive information…


#15

just curious, why there was no discussion at all about the side effects? as I knew, dut was more powerful then fin, but it also had greater side effects.
plz correct me if I’m wrong