Equol
Research reviewed: Up until 03/2026
Equol is a dietary supplement with 9 published peer-reviewed studies involving 870 participants, researched for Menopause Symptoms, Bone Health, Metabolic Health and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Menopause Symptoms
ModerateBone Health
ModerateMetabolic Health
ModerateProstate Health
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Menopause Symptoms
To evaluate S-Equol supplementation for reduction of menopausal hot flushes
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate S-Equol supplementation for reduction of menopausal hot flushes
Dose
10 mg S-Equol three times daily
Participants
266 postmenopausal women (non-Equol producers)
Duration
12 weeks
Results
S-Equol supplementation significantly reduced hot flush frequency (−51% vs −20% placebo) and improved Kupperman index scores. Greatest benefit in women with frequent severe hot flushes. Well tolerated.
How They Measured It
Hot flush frequency, hot flush severity score, Kupperman index, serum Equol levels
To compare Equol supplementation vs HRT in terms of menopausal symptom relief
Study Type
Randomised controlled trial
Purpose
To compare Equol supplementation vs HRT in terms of menopausal symptom relief
Dose
S-Equol 40 mg daily vs low-dose HRT
Participants
180 postmenopausal women (non-Equol producers)
Duration
6 months
Results
S-Equol produced significant menopausal symptom reduction comparable to low-dose HRT for hot flushes and night sweats, without endometrial stimulation. HRT was superior for vaginal symptoms.
How They Measured It
Hot flush frequency/severity, vaginal atrophy, MENQOL, bone turnover markers
Bone Health
To evaluate S-Equol supplementation on bone mineral density and turnover markers
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate S-Equol supplementation on bone mineral density and turnover markers
Dose
10 mg S-Equol twice daily
Participants
150 postmenopausal women
Duration
2 years
Results
S-Equol supplementation significantly preserved lumbar spine BMD (0.0% change vs −1.1% in placebo) and reduced CTX bone resorption marker. P1NP formation marker also significantly higher in treatment group.
How They Measured It
DXA scan, CTX, P1NP, osteocalcin, bone-specific alkaline phosphatase
To characterize the mechanisms by which Equol modulates bone cell activity
Study Type
In vitro study
Purpose
To characterize the mechanisms by which Equol modulates bone cell activity
Dose
1-100 nM S-Equol
Participants
MC3T3-E1 osteoblasts and RANKL-stimulated osteoclast cultures
Duration
7-14 days
Results
S-Equol stimulated osteoblast differentiation markers (osteocalcin, collagen), increased OPG expression, and suppressed osteoclastogenesis via reduced RANKL signaling. Mechanism involves ER-β and androgen receptor activation.
How They Measured It
Osteoblast differentiation, osteocalcin, collagen synthesis, osteoclast formation, RANK-L/OPG ratio
Metabolic Health
To evaluate S-Equol supplementation on central adiposity and metabolic risk factors in overweight postmenopausal women
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate S-Equol supplementation on central adiposity and metabolic risk factors in overweight postmenopausal women
Dose
20 mg S-Equol daily
Participants
90 overweight postmenopausal women
Duration
6 months
Results
S-Equol supplementation significantly reduced waist circumference (−2.4 cm) and visceral adipose tissue (−8%), and improved fasting glucose and triglycerides compared to placebo. HOMA-IR showed a trend to improvement.
How They Measured It
Waist circumference, visceral adipose tissue (CT scan), fasting glucose, triglycerides, insulin
Prostate Health
To evaluate S-Equol supplementation in men with BPH and elevated PSA
Study Type
Randomised double-blind placebo-controlled trial
Purpose
To evaluate S-Equol supplementation in men with BPH and elevated PSA
Dose
10 mg S-Equol three times daily
Participants
120 men with BPH and elevated PSA
Duration
6 months
Results
S-Equol supplementation significantly reduced PSA velocity, reduced prostate volume (−6%), improved IPSS symptom score, and reduced DHT without significantly affecting total testosterone. Favorable safety profile.
How They Measured It
PSA, prostate volume, IPSS, testosterone, DHT, ER-α/β activity
To investigate how Equol prevents DHT-stimulated prostate cell growth
Study Type
In vitro study
Purpose
To investigate how Equol prevents DHT-stimulated prostate cell growth
Dose
1-100 nM S-Equol
Participants
LNCaP and BPH-1 prostate cell lines
Duration
48-72 hours
Results
S-Equol directly bound DHT, inhibited its interaction with the androgen receptor, and significantly reduced DHT-stimulated prostate cell proliferation, offering a novel mechanism distinct from 5α-reductase inhibitors.
How They Measured It
5α-reductase activity, DHT binding, prostate cell proliferation, androgen receptor transcription
To evaluate the evidence for Equol in hormonal health, bone, and metabolic outcomes
Study Type
Systematic review
Purpose
To evaluate the evidence for Equol in hormonal health, bone, and metabolic outcomes
Dose
S-Equol supplementation and Equol producer status studies
Participants
Review of 25 clinical studies
Duration
Various
Results
S-Equol demonstrates superior health benefits for menopausal symptoms, bone health, and prostate health compared to other soy isoflavones. Its unique DHT-binding and ER-β-selective mechanisms explain these effects.
How They Measured It
Systematic review of clinical trials and observational studies on Equol producer status and health outcomes
To investigate the gut microbial production of Equol and its health implications
Study Type
Systematic review
Purpose
To investigate the gut microbial production of Equol and its health implications
Dose
Dietary isoflavone intake (precursor)
Participants
Review of 20 studies
Duration
Various
Results
Only ~30-50% of people produce Equol from daidzein due to gut microbiome variability. Equol producers show greater benefits from soy isoflavone intake for menopausal symptoms and prostate health. S-Equol supplements bypass this variability.
How They Measured It
Systematic review of studies on Equol producer status, gut bacteria, and health outcomes
Frequently Asked Questions
Common questions about Equol research
There are currently 9 peer-reviewed studies on Equol (Equol), involving 870 total participants. Research covers Menopause symptoms, Bone health, Metabolic health and 1 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (9 human studies), and reported outcomes.
Equol has been researched for: Menopause symptoms, Bone health, Metabolic health, Prostate health. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 9 out of 9 studies are human trials. Human trials carry more weight in our evidence scoring system.
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