I am thinking of starting Dutasteride, but I am very concerned about the fact that it inhibits the 5ar1 enzyme that is present in the brain in measurable amounts. Dutasteride at the usual 0.5mg dosage inhibits about 50% of 5ar1. I am thinking of taking dutasteride at a slightly reduced dosage of 0.375mg daily, achieved by taking three 0.5mg capsules over each four-day period. Can anyone tell me what percentage of the 5ar1 enzyme would be likely to be inhibited by this dosage? My guess is that it is somewhere between 30 and 40 percent, which would obviously be significantly less risky than taking dutasteride at the usual 0.5mg dose. Also, how much of the type 2 enzyme would the 0.375mg dose be likely to inhibit? I would guess about 96%, perhaps? Thanks very much for your replies.
5ar1 inhibition rate from dutasteride at a 75% dose (3 capsules in each 4 day period)?
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cthulhu2.0
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If you are lowering the dutasteride dosage, doesn't it make mores sense to just switch to finasteride since Androgenetic Alopecia is linked to type II DHT and not type I?
I'm not really expecting anyone to know the exact amount. I was just hoping somebody might be able to give me an approximation of what it is likely to be.
I suspect that type 1 5ar also plays a role in Androgenetic Alopecia. This is shown by the fact that dutasteride at a 0.5mg daily dose is less effective than at a 2.5mg daily dose. Both doses inhibit virtually the same amount of type 2 5ar, but quite different amounts of the type 1 enzyme. I think there's no doubt that low dose dutasteride (for instance, 0.5mg every other day or every third day) is more effective than finasteride, although this is going to be mostly because of the more complete inhibition of 5ar2 rather than the additional small amount of 5ar1 inhibition that these dosages of dutasteride carry out. I'm trying to find out what would be a good dosage of dutasteride that would be effective at treating Androgenetic Alopecia, but also one that inhibits only a relatively small amount of 5AR1 and therefore is less risky than the standard 0.5mg dosage.
Here is a rough graph.
It does not.
Going by the long half life of Dutasteride, it does not make sense to take intermittent doses. I would just go ahead and take 1 mg ED of finasteride, which would be slightly better than 0.1 mg of dutasteride ED.
The higher doses of Dutasteride you take, the more you will also inhibit 5-AR I, and as a result, you will get marginal benefits for hair. Again, you could still keep your hair a little short and use Ketoconazole 2% shampoo every 2-3 days, since it works at reducing scalp DHT similar to the effects of 5-AR I inhibition.
isishearmyplea
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xredstarx
male pattern baldness is related to which type? I or II or which type has more implication. can .25 mg finasteride ED work for frontal maintenance/regrowth ??
male pattern baldness is related to which type? I or II or which type has more implication. can .25 mg finasteride ED work for frontal maintenance/regrowth ??
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What I meant by inhibits many times more type 2AR than finasteride is that the type 2 DHT levels will be many times lower than they would be if you had taken finasteride instead, which is true
To isis type 2 is related to hair loss. There is no evidence that type 1 does anything to make you lose your hair
I saw you on misc btw (Redstar)
To isis type 2 is related to hair loss. There is no evidence that type 1 does anything to make you lose your hair
I saw you on misc btw (Redstar)
isishearmyplea
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Thanks zzzzz. I saw some idiot post on BTT saying that type I is in more amount in scalp and causes male pattern baldness.
Are you referring to my .25 mg question?? honestly brother i am not seeing any results (4 months in) so i kinda just keep asking this question for some sort of moral support, i know its weird :/
isishearmyplea
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Guess i will. Thanks!! 
Type II by far in most people.
I wouldn't say regrowth, since it isn't really a primary effect of finasteride. But yes, it will maintain just fine.
Yes, I contributed a big hair loss thread over there back in December.
Finasteride and Dutasteride actually inhibit roughly the same amounts of 5-AR II enzymes at their proper doses, say for example 5 mg of Finasteride vs 0.5 mg of Dutasteride. The reason why Dutasteride works better than Finasteride in general is because of the 5-AR I inhibition, which can still have some androgenic effects on hair tissue, and the constant inhibition of 5-AR enzymes due to it's long half life, but the latter's effect is insignificant in my view.
cthulhu2.0
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Yes, a dutasteride dose of .5mg is superior to 1mg dose of finasteride but he is referring to the case of lower the dutasteride dose to avoid dht type 1 inhibition. My argument was that he would likely want to take finasteride if he is able to inhibit type II alpha reductase by the same degree compared to a lower doses of dutasteride and still leave type I alpha reductase intact.
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which seems to be his main goal
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In the graph you posted dutasteride AR2 inhibition curve runs close to 0 while the 5mg finasteride line clearly runs above that line though
That graph is a hypothetical representation, not a real study.
You are right that dutasteride is more effective at inhibiting 5-AR II enzymes mg-for-mg. But you fail to understand that there is a plateau reached for both drugs very early on. Dutasteride is almost 3 times more potent at inhibiting 5-AR II than Finasteride, and 120 times more potent at inhibiting 5-AR I, according their respective IC50 values. So with that said, 1 mg and above of finasteride should inhibit almost all 5-AR II activity, especially with repeated dosing.
Don't forget that Finasteride and Dutasteride are both similarly effective at decreasing prostatic mass, which is 5-AR II dominant. This is a good proxy for my hypothesis.
As I said earlier, I suspect that 5ar1 does play a role in Androgenetic Alopecia, shown by the fact that a daily dose of 2.5mg Dutasteride has been found to be more effective at increasing hair counts than a daily dose of 0.5mg. Both these doses inhibit essentially 100% of 5ar2, but significantly different amounts of 5ar1 (0.5mg = 50% 5ar1 inhibition, 2.5mg = over 80% 5ar1 inhibition). It would seem obvious that the greater effectiveness of 2.5mg is therefore due to its greater inhibition of 5ar1.
Or, the 2.5 mg of dutasteride reached effective plasma levels faster than 0.5 mg, thus regrowing more hair.
5-AR I's role in male pattern baldness is very limited, almost insignificant, but still exists.
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I heard one person say once that the differences in hair growth in the 6 month study comparison of finasteride and dutasteride resulted in different results (with dutasteride being more effective than finasteride, and higher doses of dutasteride being the most effective) because of the ability of dutasteride to achieve results faster... but in the end over a longer period he thought that they might yield almost the same results
That's not the case, they both start working right away. Dutasteride is just more effective than 5 mg of finasteride because of it's ability to suppress even more DHT on scalp tissue in doses crossing the 5-AR II inhibition plateau. Which is typically more than 0.1 mg ED.
Some interesting posts you guys have made. So what dose of dutasteride would you say is a good dose to take in terms of getting results better than those that would be achieved by finasteride, but also a dose that limits 5ar1 inhibition as much as possible? It may be that more research is needed to answer this question, but it would appear to me that 0.5mg daily, which inhibits approximately 50% of 5ar1, is not the best choice of dose for those who are trying to find the most sensible compromise between getting good results while also trying to limit 5ar1 inhibition as much as possible. A slightly lower dutasteride dosage of perhaps 0.33mg may be a better choice for people such as myself who have these concerns over 5ar1 inhibition. Any thoughts anyone? Thanks.