Hey everybody, just read an article in the globe about melatonin that mentioned it as an estrogen blocker. Something about a recent study showing it to reduce estrogen and curb PMS symptoms in women- any truth to this? Thanks!
Melatonin was shown to reduce estrogen in elderly women. Here is the abstract.
Neuroendocrinol Lett 2002 Apr;23 Suppl 1:17-9 Related Articles, Books, LinkOut
Effects of six months melatonin treatment on sleep quality and serum concentrations of estradiol, cortisol, dehydroepiandrosterone sulfate, and somatomedin C in elderly women.
Pawlikowski M, Kolomecka M, Wojtczak A, Karasek M.
Institute of Endocrinology, Medical University of Lodz, 91-425 Lodz, Sterling Str.3, Poland. TEL.: +48 42 6365427 FAX: +48 42 6324854. pawlikowski.m@wp.pl
OBJECTIVES: The role of melatonin is aging is still under debate. Therefore, an open pilot study on the effects of melatonin administration on some sleep parameters, routine hematological and biochemical parameters, and concentrations of hormones was performed in elderly women. SUBJECTS AND METHODS: The study was performed on 14 women (volunteers), aged from 64 to 80 years (mean age 71+/-4.6 years). Melatonin (2 mg daily at 19:00 h) was administered during 6 months. Before and after melatonin treatment the peripheral venous blood samples were taken in the morning (approx. at 08:00 h) after the overnight fast. The total blood count, glucose, total cholesterol, LDL, HDL, and triglycerides were estimated by routine laboratory methods. The serum concentrations of the following hormones were determined: 17-beta-estradiol, dehydroepiandrosterone sulfate (DHEAS), cortisol, and somatomedin C (IGF-I). Additionally, before and after 6 months of melatonin therapy the investigated subjects answered to a questionnaire dealing with sleep parameters and self-estimation of general health status. RESULTS: In 35.7% of investigated subjects an improvement in general sleep quality and in such sleep parameters as sleep initiation, sleep latency, number of awakenings episodes, wake time after sleep onset, was observed. A significant decrease of estradiol concentrations was observed after 6 months of the melatonin treatment in comparison to initial levels. IGF-I was found to be slightly but significantly increased after the 6 months melatonin therapy. Cortisol levels did not change significantly, during the melatonin treatment. DHEAS concentrations increased after melatonin therapy. Moreover, a tendency towards a higher DHEAS/cortisol ratio was found after 6 months of treatment. Melatonin treatment did not influence significantly either the parameters of total blood count or glucose and serum lipids levels. CONCLUSIONS: On the basis of this preliminary open study it seems that melatonin administration may be beneficial for elderly subjects.
PMID: 12019346 [PubMed - in process]
This study may have been done in elderly women; however, there is another study which demonstrated that melatonin reduced estrogen receptor alpha transactivation in breast cancer cells. If this also applies to normal breast tissue melatonin may be able to prevent estrogen induced gyno in men. This has a limited application however since melatonin induces sleep.
Breast Cancer Res Treat 2002 Jan;71(1):37-45 Related Articles, Books, LinkOut
Melatonin inhibits estrogen receptor transactivation and cAMP levels in breast cancer cells.
Kiefer T, Ram PT, Yuan L, Hill SM.
Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA.
We have previously demonstrated that the pineal hormone, melatonin, can inhibit the growth of estrogen receptor-alpha (ERalpha)-positive breast cancer cells and suppress ERalpha gene transcription. To investigate the relationship between the estrogen response pathway and melatonin’s growth inhibition, ERalpha-positive MCF-7 human breast cancer cells were transiently transfected with an estrogen response element (ERE) luciferase reporter construct and then treated with melatonin (10(-9)-10(-6) M) for 30 min followed by 10(-9) M 17-beta-estradiol (E2) or treated with each compound alone. Melatonin pre-treatment significantly reduced E2-induced ERalpha transactivation and ERalpha-ERE binding activity. We also conducted experiments to determine if melatonin modulates cAMP levels in MCF-7 cells. Melatonin inhibited the forskolin-induced and E2-induced elevation of cAMP levels by 57 and 45%, respectively. These data indicate that melatonin can act as a biological modifier to affect ERalpha transcriptional activity by regulating signal transduction pathways which impinge on the ERalpha and by altering E2-mediated ERalpha transactivation and ERalpha DNA binding activity.
PMID: 11859872 [PubMed - in process]
Melatonin was considered for inclusion in M, but decided against. I wasn’t on the design team for that product, but conferred occasionally on it – I don’t recall the details on melatonin, due to some kind of memory failure on this point, but I do recall agreeing on the reasoning.
Melatonin exerts its biological effects by decreasing cyclic AMP levels,and thus decreases the activity of every hormone that requires cyclic AMP as its second messenger for actions.Melatonin also increases the production of somatostatin that prevents the release of growth hormone.Somatostatin also works by decreasing cyclic AMP levels.
Hope this helps.
Hi Bill,
I’ve had a lifelong sleep disorder and use Melatonin to control it, it helps me fall asleep. It’s been a godsend for me, nothing else has really worked.
So I’m glad you guys didn’t put it in M, because you would have had everybody getting drowsy and falling asleep! 
Striker, yes, that side effect was also a factor in in not being included in M, and also as Wstrainer brought out, there are other in-depth reasons as well.