St John’s wort may ease hot flushes

Many individuals are aware of the anti-depressant properties of St Johns Wort and I have previously written about the herb in this regard and in relation to Seasonal Affective Disorder (SAD).  New evidence now suggests that the herb may be useful during the menopause.

A recent study (1) was set up to compare the efficacy of St John’s wort with an inactive placebo in women who were experiencing hot flashes.  Hot flashes occur because of the decline of a hormone, oestadiol, during the menopause (in women who are perimenopausal) and also premenopausally and postmenopausally.  A total of 100 women participated in the clinical trial, the average age of the women was 50 years old.  Half of the women received the herb and half received the inactive placebo.  On the 8th week of treatment there was a statistically significant difference in hot flash frequency between the two groups, with the group receiving the herb experiencing fewer hot flushes than the placebo group.  In addition the women who received St John’s wort also had a decrease in the severity of hot flashes in the 4th and 8th week of treatment.  Among the women taking St John’s wort, the average number of hot flashes declined from around four per day at the start of the study, to less than two per day at week eight.  The authors conclude that St John’s wort can be used as an effective treatment for the hot flash symptoms of perimonopausal and postmenopausal women.

During my research I came across two other study papers (2,3) which looked at St John’s wort for menopausal symptoms, both papers were preliminary-small scale trials.  Both found the herb was useful in some regard.  One (2) found that women who received the herb reported significantly better menopause-specific ‘quality of life’ and significantly fewer sleep problems than women receiving placebo.  The other paper (3) found that St John’s wort aided psychological as well as hot-flash symptoms in menopausal women, the women also found that their sexual well-being improved after treatment with St John’s wort.


It is not precisely known how St John’s wort is acting.  The herb does contain estrogen-like plant compounds called phytoestrogens, and it could be that these compounds explain the benefits seen in this study – but further research would be needed in order to confirm this.  Further trials are also needed to see if the effects of the herb on hot-flashes and other menopausal symptoms, can be replicated on a larger scale, before firm recommendations for the use of St John’s wort in menopausal women can be made. 

Another reason that St John’s wort may be useful to women going through the menopause is for its anti-depressant action.  Many individuals would rather not take anti-depressant medication because of the various side-effects and the herb could be a valuable alternative.  This seems particularly relevant since a recent (4) study found that older women who take an antidepressant seem to have a small but noteworthy increased risk of stroke and death compared to older women not on an antidepressant medication.  This is quite worrying due to the increasing numbers of people taking anti-depressant medications.  Further investigations and research needs to be carried out in order to evaluate the risks, but I alsdo think that any investigation looking into alternatives is also worthwhile.  Please also read my previous posts relating to depression for useful ideas.

St John’s wort is generally considered safe when dosage instructions are followed, however it is always best to talk to a medical doctor prior to supplementing with this herb as it can have powerful effects and is also known to interact with certain medications. 

(1)Khadijeh A eta l.  2010.  Effect of St John’s wort on severity, frequency, and duration of hot flashes in premenopausal, perimenopausal and postmenopausal women: a randomized, double-blind, placebo-controlled study.  Menopause.  February 2010 EPub ahead of print doi: 10.1097/gme.0b013e3181b8e02d
(2)Al-Akoum M et al.  2009.  Effects of Hypericum perforatum (St. John’s wort) on hot flashes and quality of life in perimenopausal women: a randomized pilot trial. Menopause. 16(2):307-14.
(3)Grube B et al.  1999.  St. John’s Wort extract: efficacy for menopausal symptoms of psychological origin. Adv Ther. 16(4):177-86.
(4)Smoller JW et al.  2009.  Antidepressant Use and Risk of Incident Cardiovascular Morbidity and Mortality Among Postmenopausal Women in the Women’s Health Initiative Study.  Arch Intern Med.  169: 2128 – 2139.

Written by Ani Kowal