Big thanks to
@jonnywalker93 for providing a very interesting finasteride study that I'm now shortly comparing to Brotzu, and which I'm attaching to this message.
The finasteride study was conducted in 2000 and lasted 48 weeks. It shows how anagen hairs increase progressively over time and how telogen hairs decrease while on finasteride.
The Brotzu study was conducted in 2016 and lasted "6 months" from May to December (not specified how many weeks, nor the exact start/endpoints).
Mean age in finasteride study was 30,2 +- 0.6 (standard deviation provided).
Mean age in Brotzu study was 46.6 +- 6.4 (standard deviation provided).
Number of patients in finasteride study was 220.
Number of patients in Brotzu study was 30 (males).
I'll consider only the male subjects in the Brotzu studies because of the differences between male pattern baldness and FPB but also mainly because of the different composition of the female lotions.
I'm reporting exactly the numbers listened by the two studies. Standard deviation was used in both studies as a measure of the standard error SE.
FINASTERIDE
Anagen hair: +18.1 (from 124.4+-4.9 to 142.5+-5.4)
Telogen hair: -10.9 (from 75.1+-4.0 to 64.2+-3.3)
Hair count: +7.4 (+3.7%) (from 200.0+-5.2 to 207.4+-5.4)
BROTZU:
Anagen hair: +5.0 (from 64.3+-10.5 to 69.3+-11.0)
Telogen hair: -5.0 (from 35.7+-10.5 to 30.7+-11.0)
Hair count: +2.3 (+1.6%) (from 144.5+-29.0 to 146.8+-30.5)
I don't want to post screenshots of Brotzu study, but for both of them all the results listed were statistically significant (p<0.05).
I'm proposing a brief and synthetic yet probably FLAWED analysis, but I want to get to the point: are treatments even comparable?
The finasteride study reports this:
"
In this study, finasteride treatment increased the amount and percentage of anagen hair and improved the anagen to telogen ratio in men with male pattern
hair loss. Anagen hair count, first measured at 24 weeks, increased progressively over 48 weeks for
finasteride-treated subjects. In contrast, placebo-treated subjects lost anagen hair during the study, consistent with the progressive shortening of the anagen phase duration that leads to the hallmark of androgenetic alopecia, follicular miniaturization. By 48 weeks, treat-
ment with finasteride had resulted in a 26% net improvement in anagen hairs compared with placebo. This increase in anagen hair count, together with the
increase in the anagen to telogen ratio, is direct evidence that treatment with finasteride promotes the
conversion of hair follicles into the anagen phase. While the duration of the anagen phase decreases between successive growth cycles in male pattern hair
loss, the length of the lag phase also increases, contributing to the rate of apparent hair loss. Thus,
the increase in the anagen hair count observed with finasteride treatment could be due to the reversal of both of these processes. A more precise characterization of the effect of finasteride on the duration of the specific phases of the hair growth cycle would require that individual hair follicles be followed over successive cycles and the length of each phase measured. Regardless, the results of this study confirm that
finasteride treatment increases total hair count by increasing actively growing anagen hair.
The ratio of anagen to telogen hairs was also shown to increase progressively over 48 weeks of finasteride treatment. The increase in the anagen to telogen ratio with finasteride treatment at 24 weeks reflected
primarily the changes in anagen hair count, as telogen hair count had not significantly changed from baseline.
As the duration of the telogen phase is not altered in male pattern hair loss, finasteride treatment is not likely to affect this phase directly. Rather, as anagen phase is prolonged, fewer hairs are in telogen. Thus, the telogen hair count would be expected eventually to decrease with finasteride, due to continued prolongation of the anagen phase. This is consistent with the observation that, in this study, the reduction in the telogen hair count, and its favourable effect on the anagen to telogen ratio, followed the increase in the anagen hair count with finasteride. These positive changes in the hair cycle, associated with the progressive improvement in scalp coverage observed in treated subjects, imply favourable consequences on clinically important aspects of hair quality (thickness, length, growth rate, growth duration and/or pigmentation) in men on treatment. "
Brotzu study stopped at 6 months. There were significant differences between men and women regarding the onset of the benefits. Brotzu study says:
"
Men experienced a constant improvement, at the end of treatment (6 months), 63.3% of them had experienced an increase in total hair number (Figure 5). A significant increase in anagen hair and a significant decrease in telogen hair were observed starting from 3 months, together with a significant increase in the pull test score. The wash test provided a significantly better score already starting from the first month. No significant increase in the hair diameter was observed at any time point. Women, differently than men, experienced a significant increase in the total number of hair already after the first month of treatment; at 6 months, most (89.7%) had experienced improvement (Figure 6). In women, a significant increase in anagen hair and a significant decrease in telogen hair were observed starting from the first month. Pull test and wash test scores also improved starting from the first month of treatment. "
Brotzu team provides this explanation:
"
Response of men was slightly different than that of women; the lotion had a significant effect on the total hair number in women, and its effects on the number of the anagen and telogen hair as well as those on the pull test appeared later in men than in women. These differences might be due to the different hormonal profile of the two sexes. At present, in fact, the role of androgens in female alopecia is still unclear (Olsen et al., 2001; Ioannides et al., 2015; Torres et al., 2015). Further studies should therefore be granted to investigate the differences observed in the present investigation concerning the response of women and men. "
In the finasteride study, we have this note in the conclusion:
"
As in men, similar hair growth cycle abnormalities are observed in women with androgenetic alopecia. However, results from a placebo-controlled study of postmenopausal women with androgenetic alopecia demonstrated no benefit of finasteride after 1 year. This difference in treatment efficacy between men and women may be due to gender differences in the role of type 2 5a-reductase in the pathophysiology of androgenetic alopecia. "
This may be another confirmation of the differences between male and female groups in Brotzu study.
Now, re-analyzing the anagen phase stuff and the links to cosmetic improvements, I found this over the web. It is a 5 year study on Finasteride's effect on Androgenetic Alopecia. Title:
Long-term (5-year) multinational experience with finasteride 1 mg in the treatment of men with androgenetic alopecia
European Journal of Dermatology. Volume 12, Number 1, 38-49, Janvier - Février 2002, Thérapie
The most interesting part in this regard is this:
"
Based on the predefined endpoints utilizing photographic methods (hair counts and global photographic assessment), peak efficacy was observed at one to two years of treatment with finasteride. This observation of an apparent peaking effect is likely due, in part, to the previously-reported beneficial effects of finasteride on the hair growth cycle based on a phototrichogram study [26]. In that study, initiation of finasteride treatment was shown to increase the number of anagen-phase hairs and to increase the anagen to telogen ratio, consistent with normalization of the growth cycles of previously miniaturized hairs due to the release of hair follicles from the inhibitory effects of DHT [26]. Consistent with these results, finasteride treatment was also shown to increase the growth rate and/or thickness of hairs, based on analysis of serial hair weight measurements [27]. Because these beneficial changes in the hair growth cycle are dependent on when therapy with finasteride is initiated and occur rapidly, the affected hairs are driven to cycle in a synchronous manner. If these hairs have somewhat similar anagen phase durations, they would enter telogen phase as the anagen (and catagen) phase ended, followed by subsequent shedding, in a partially synchronized fashion. This would be expected to produce a gradual decline from peak hair count after a period of time equal to the average anagen phase duration. Eventually, as subsequent growth cycles recurred, these hairs would be expected to become increasingly independent, thereby losing their synchronous character as their growth cycles further normalized over time, leading to a sustained increase in hair count at a plateau above baseline, as suggested by the 5-year data presented here."
This would also explain why some men experience a sudden loss of gains on finasteride: if their hair is synchronized from the initiation of finasteride a year or two (or more) ago, when their hair reaches the telogen phase there would be massive shedding. This apparent loss would remain until the hair started growing again (3 months) and would take several more months for the hair to grow and provide a cosmetic improvement. Perhaps some of these guys who drop finasteride when they think results are fading are not giving enough time for the synchronized telogen phase to end.
Then, of course, we have all the good explanations provided by prof.Tosti in my last post and published on the journal to support the Anagen phase boost as the fundamental way of work of finasteride.