UC San Diego

Background

Herbal supplements are widely used for vasomotor symptoms.

Objective

To test the efficacy of 3 herbal regimens and hormone therapy for relief of vasomotor symptoms compared with placebo.

Design

1-year randomized, double-blind, placebo-controlled trial conducted from May 2001 to September 2004.

Setting

Group Health, Washington State.

Participants

351 women age 45 to 55 years with 2 or more vasomotor symptoms per day; 52% of the women were in menopausal transition and 48% were postmenopausal.

Measurements

Rate and intensity of vasomotor symptoms (1 = mild to 3 = severe), and Wiklund Vasomotor Symptom Subscale.

Interventions

1) Black cohosh, 160 mg daily; 2) multibotanical with black cohosh, 200 mg daily, and 9 other ingredients; 3) multibotanical plus dietary soy counseling; 4) conjugated equine estrogen, 0.625 mg daily, with or without medroxyprogesterone acetate, 2.5 mg daily; or 5) placebo.

Results

Vasomotor symptoms per day, symptom intensity, Wiklund Vasomotor Symptom Subscale score did not differ between the herbal interventions and placebo at 3, 6, or 12 months or for the average over all the follow-up time points (P > 0.05 for all comparisons) with 1 exception: At 12 months, symptom intensity was significantly worse with the multibotanical plus soy intervention than with placebo (P = 0.016). The difference in vasomotor symptoms per day between placebo and any of the herbal treatments at any time point was less than 1 symptom per day; for the average over all the follow-up time points, the difference was less than 0.55 symptom per day. The difference for hormone therapy versus placebo was -4.06 vasomotor symptoms per day for the average over all the follow-up time points (95% CI, -5.93 to -2.19 symptoms per day; P < 0.001).

Limitations

The trial did not simulate the whole-person approach used by naturopathic physicians. Differences between treatment groups smaller than 1.5 Vasomotor symptoms per day cannot be ruled out.

Conclusion

Black cohosh used in isolation, or as part of a multibotanical regimen, shows little potential as an important therapy for relief of vasomotor symptoms.

Clinical trials registration number

NCT00169299.