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Study #1

This study suggests that Saw Palmetto extract inhibited both type one and two forms of 5 alpha-reductase, a major cause of male pattern baldness because it converts testosterone to DHT.


TITLE: Human prostatic steroid 5 alpha-reductase isoforms - a comparative study of selective inhibitors.


AUTHOR Iehlé C; Délos S; Guirou O; Tate R; Raynaud JP; Martin PM – Journal of Steroid Biochemistry


ABSTRACT The present study describes the independent expression of the type 1 and 2 isoforms of human 5 alpha-reductase in the baculovirus-directed insect cell expression system and the selectivity of their inhibition. The catalytic properties and kinetic parameters of the recombinant isozymes were consistent with published data. The type 1 isoform displayed a neutral (range 6-8) pH optimum and the type 2 isoform an acidic (5-6) pH optimum. The type 2 isoform had higher affinity for testosterone than did the type 1 isoform (Km = 0.5 and 2.9 microM, respectively). Finasteride and turosteride were selective inhibitors of the type 2 isoform (Ki (type 2) = 7.3 and 21.7 nM compared to Ki (type 1) = 108 and 330 nM, respectively). 4-MA and the lipido-sterol extract of Serenoa repens (LSESr) markedly inhibited both isozymes (Ki (type 1) = 8.4 nM and 7.2 micrograms/ml, respectively; Ki (type 2) = 7.4 nM and 4.9 micrograms/ml, respectively). The three azasteroids were competitive inhibitors vs substrate, whereas LSESr displayed non-competitive inhibition of the type 1 isozyme and uncompetitive inhibition of the type 2 isozyme. These observations suggest that the lipid component of LSESr might be responsible for its inhibitory effect by modulating the membrane environment of 5 alpha-reductase. Partially purified recombinant 5 alpha-reductase type 1 activity was preserved by the presence of lipids indicating that lipids can exert either stimulatory or inhibitory effects on human 5 alpha- reductase


Study #2:

This study shows Saw Palmetto inhibited the formation of the Testostrone metabolites studied, including DHT, a major cause of male pattern baldness.


TITLE: Testosterone metabolism in primary cultures of human prostate epithelial cells and fibroblasts.


AUTHOR Délos S; Carsol JL; Ghazarossian E; Raynaud JP; Martin PM – Journal of Steroid Biochemistry


ABSTRACT We compare testosterone (T) metabolism in primary cultures of epithelial cells and fibroblasts separated from benign prostate hypertrophy (BPH) and prostate cancer tissues. In all cultures, androstenedione (delta 4) formed by oxidation of T by 17 beta- hydroxysteroid dehydrogenase (17 beta-HSD) represented 80% of the metabolites recovered. The amounts of 5 alpha-dihydrotestosterone (DHT), formed by reduction of T by 5 alpha-reductase (5 alpha-R), were small: 5 and 2% (BPH) and 8 and 15% (adenocarcinoma) for epithelial cells and fibroblasts, respectively. Northern blot analysis of total RNA from epithelial cells (BPH or adenocarcinoma) attributed the reductive activity to the 5 alpha-reductase type 1 isozyme and oxidative activity to the 17 beta-HSD type 2. In cancer fibroblasts, only little 17 beta-HSD type 2 mRNA was detected. The 5 alpha- reductase inhibitors, 4-MA (17 beta-(N,N-diethyl)carbamoyl-4-methyl-4-aza-5 alpha- androstan-3-one) and finasteride, inhibited DHT formation with a preferential action of 4- MA on epithelial cells (BPH or adenocarcinoma) and of finasteride on fibroblasts from adenocarcinoma. Neither inhibitor acted on delta 4 formation. On the other hand, the lipido-sterol extract of Serenoa repens (LSESr, Permixon, Saw Palmetto) inhibited the formation of all the T metabolites studied [IC50 S = 40 and 200 micrograms/ml (BPH) and 90 and 70 micrograms/ml (adenocarcinoma) in epithelial cells and fibroblasts, respectively]. These results have important therapeutic implications when selecting appropriate treatment options for BPH




This study shows that Nettles extract inhibits enzymes such as 5 alpha reductase (the enzyme that causes testosterone to convert to DHT). It is the DHT metabolite of testosterone that is known to cause excess hair loss at the top of the head.


AUTHOR R. Hartmann et al.


Study Summery

The extract of nettle root (Urtica dioica L., Urticaceae) partially blocked the action of two enzymes involved in the body's production of dihydrotestosterone and estrogen. The in vitro (laboratory) study showed that nettle root extract was effective in inhibiting these two enzymes (5alpha-reductase and aromatase).


Dr. A Vogel, a Swiss herbalist know throughout the world, advocates Nettle for stimulating hair growth and Dr. Rudolf Fritz Weiss, M.D., the dean of German herbal physicians and author of Herbal Medicine also supports the use of Nettles for those with thinning hair.




Green Tea: This study shows that Green Tea has compounds in it that are potent inhibitors of type 1 alpha-reductase. 


TITLE: Selective inhibition of steroid 5 alpha-reductase isozymes by tea epicatechin-3- gallate and epigallocatechin-3-gallate.


AUTHOR Liao S, Hiipakka RA. Ben May Institute, University of Chicago, IL 60637, USA. – Journal of Steroid Biochemistry


ABSTRACT Inhibitors of 5 alpha-reductase may be effective in the treatment of 5 alpha- dihydrotestosterone-dependent abnormalities, such as hair loss. The green tea catechins, (-) epigallocatechin-3- gallate and (-) epicatechin-3-gallate, but not (-)epicatechin and (-)epigallocatechin, are potent inhibitors of type 1 but not type 2 5 alpha-reductase. These results suggest that certain tea gallates can regulate androgen action in target organs.




This study shows that the active principle that causes the heat in capsicum is a crystalline alkaloid generically called capsaicin induces the release of substance P(SP) which is believed to play an important role in the murine hair growth and cycle.


TITLE: Effect of Coapplication of Capsaicin and Minoxidil on the Murine Hair Growth


AUTHOR Won-Soo Lee, Hyung Jin Ahn, Young Hee Kim Department of Dermatology. Yonsei University Wonju College of Medicine, Wonju. Korea 


ABSTRACT Capsaicin induces the release of substance P(SP) which is believed to play an important role in murine hair growth and cycle. We divided the mice into 4 groups, i.e., control group, capsaicin group, and coapplied group. And then, we examined the hair growth macroscopically, and the percentage of the area of hair regrowth by image analysis using phototrichogram at the 0, the 5th, 10th, 15th, 20th, 25th, and 30th day. Also we examined the morphologic changes of hair follicles and subcutis, and the number of mast cells by microscopy, and[methyl-3H] thymidine uptake by scintillation counter. In this study, we observed that capsaicin can not only induce the anagen phase quickly, but also sustain constant effect on the linear hair growth.

CLINICAL STUDIES: Active ingredients used in REJUVEN

Regrowth Treatment that inhibit 5 alpha-reductase (a major cause of hair loss).

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