Equol (S-equol)

Q: Does S-equol help hot flashes?

In trials, mostly yes: 10 mg a day cut hot flushes by 58.7% vs 34.5% with placebo in 160 Japanese women, and a 2019 meta-analysis of 5 trials found a benefit. The Menopause Society's 2023 statement still lists equol as not recommended because the evidence is limited or inconsistent.

Q: Do I need equol if I already eat soy?

Only producers make equol from soy. In a 6-month isoflavone trial, symptoms improved only in women who produced equol, which is why most S-equol trials enrolled non-producers.

Q: Is S-equol a hormone?

No, but it acts on estrogen receptors: it binds estrogen receptor beta selectively. Trials did not find changes in blood sex hormones.

Q: Can I take S-equol if I am allergic to soy?

S-equol supplements are made by fermenting soy germ, and NCCIH notes some people are allergic to soy. One equol trial excluded people with soy allergy, so anyone with a soy allergy should check with a clinician first.

Q: Does S-equol interact with breast cancer drugs?

In a 2025 study of 24 postmenopausal women (6 per drug), 10 mg a day of S-equol for 7 days did not significantly change blood levels of anastrozole, letrozole, exemestane or tamoxifen. That study did not test whether it is safe after hormone-sensitive cancer, so ask an oncologist first.

Q: What is an equol producer?

Someone whose gut bacteria convert the soy isoflavone daidzein into S-equol. A 2015 review puts this at about 50% of Asians and 25% of non-Asians.

Q: Why does the Menopause Society not recommend equol?

Its 2023 nonhormone position statement rated the evidence for soy foods, soy extracts and equol as limited or inconsistent (Level II). Most trials were small, short and in Japanese women, for whom hot flashes are a minor complaint, as a 2015 review noted.

Also called S-equol, natural S-equol, SE5-OH, equol supplement.

Best grade B across 11 graded outcomes Other Last checked Oct 21, 2026

The short answer

From 18 sources

S-equol is the soy isoflavone metabolite that only some people's gut bacteria make. Supplements of about 10 mg a day reduced hot flushes in Japanese and US trials, and a 2019 meta-analysis of 5 trials found a benefit (grade B). The Menopause Society's 2023 statement still does not recommend equol for hot flashes, and most trials were small and industry-linked.

Every graded outcome on this page

11 rows · line = participants

Grade BHot flushes in postmenopausal women (pooled)Hot flushesn 728
Grade BHot flush frequency in equol non-producersHot flushesn 160
Grade CMenopausal symptoms and moodMoodn 134
Grade CHot flash frequency vs soy isoflavones (active comparator)Hot flushesn 102
Grade CCrow's-feet wrinklesSkinn 101
Grade CMenopausal symptoms with soy isoflavones, by equol producer statusHot flushesn 96
Grade CBone resorption and whole-body bone densityBonen 93
Grade CBone turnover markers and whole-body bone density (with resveratrol)Bonen 60
Grade CClimacteric symptoms, skin AGEs and visceral fatHot flushesn 57
Grade CHbA1c, LDL cholesterol and arterial stiffness in overweight adultsMetabolicn 54
Grade DHand osteoarthritis pain and functionJoint painn 102
8 more graded outcomes, in the evidence chapter

Key facts

What it is: S-equol (C₁₅H₁₄O₃) is made from daidzein by gut bacteria in about 50% of Asians and 25% of non-Asians, according to a 2015 review; supplements are made by fermenting soy germ with Lactococcus garvieae^1,13,10
Hot flushes: A 2019 meta-analysis of 5 randomized trials (728 women) found equol lowered hot flush scores; 3 trials were positive and 2 were not (B)⁴
Largest single trial: In 160 equol non-producing Japanese women, 10 mg a day for 12 weeks cut hot flush frequency by 58.7% vs 34.5% with placebo⁵
Expert view: The 2023 nonhormone therapy position statement of The North American Menopause Society lists the soy metabolite equol as not recommended for hot flashes (Level II, limited or inconsistent evidence)²
Producers vs non-producers: Most trials enrolled women who cannot make equol; in a 6-month soy isoflavone trial, symptoms improved only in women who could^5,12
How the body handles it: Rapidly absorbed with a plasma half-life of about 8 hours; 82% of a 10 or 30 mg dose was recovered in urine¹⁰
Safety data: Trials of up to 1 year reported no serious adverse effects and no changes in sex or thyroid hormones; a 2015 review judged the limited safety data, including breast and endometrium, not a cause for concern^7,5,13
Breast cancer hormone drugs: 10 mg a day for 7 days did not significantly change blood levels of anastrozole, letrozole, exemestane or tamoxifen in 24 healthy postmenopausal women (6 per drug)¹⁷

What it is

S-equol is made by some people's gut bacteria from the soy isoflavone daidzein; supplements supply it ready-made from fermented soy germ.

How it works

Proposed

S-equol is the form of equol that gut bacteria make from the soy isoflavone daidzein. It binds estrogen receptor beta selectively and, in vivo, antagonises dihydrotestosterone. Whether a person makes equol depends on their gut bacteria, which is the proposed reason soy isoflavones help some women's hot flushes and not others. Supplements made by fermenting soy germ with Lactococcus garvieae deliver S-equol directly, so they bypass producer status. How it reduces hot flushes is not established.^10,13,12,14

Forms side by side: ready-made S-equol and soy isoflavones

2 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.

Equol (S-equol) forms compared

2 forms

Equol (S-equol) forms compared: 2 forms by 3 attributes. Empty cells are labelled No data yet, or Not graded in the evidence row.
2 forms	S-equol from fermented soy germ (SE5-OH tablets)	Soy isoflavones (daidzein) for people who make equol themselves
Absorption in people	Rapidly absorbed, plasma half-life about 8 hours, 82% excreted in urine; producer status did not change the pharmacokinetics.¹⁰	Depends on gut bacteria; a 2015 review puts producers at about 50% of Asians and 25% of non-Asians.¹³
GI tolerance	No serious adverse effects in 12-week to 1-year trials; one systemic rash at 30 mg/day.^5,7,8	See the soy isoflavones page.¹²
Studied for	Hot flushes (B), mood (C), bone markers (C), wrinkles (C)	Menopausal symptoms, with benefit in producers only (C)

S-equol from fermented soy germ (SE5-OH tablets)
Absorption in people
Rapidly absorbed, plasma half-life about 8 hours, 82% excreted in urine; producer status did not change the pharmacokinetics.¹⁰
GI tolerance
No serious adverse effects in 12-week to 1-year trials; one systemic rash at 30 mg/day.^5,7,8
Studied for
Hot flushes (B), mood (C), bone markers (C), wrinkles (C)
Soy isoflavones (daidzein) for people who make equol themselves
Absorption in people
Depends on gut bacteria; a 2015 review puts producers at about 50% of Asians and 25% of non-Asians.¹³
GI tolerance
See the soy isoflavones page.¹²
Studied for
Menopausal symptoms, with benefit in producers only (C)

What the human research says

Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.

Trial map

11 graded outcomes, largest study first

11 graded outcomes: 9 improved, 2 mixed. The largest, a 2019 meta-analysis of 728 people on hot flushes in postmenopausal women (pooled), found an improvement.

By sizeTable

1Hot flushes in postmenopausal women (pooled)

Improved · Grade B · Meta-analysis, 728 people, 2019

Peri- or postmenopausal women in 5 randomized trials (6 trials, 779 women, reviewed)

Dose, result and source

Every graded outcome on this page, largest study first
Outcome	Found	People	Study	Who was studied
Hot flushes in postmenopausal women (pooled)	Improved	728	Grade B · Meta-analysis, 2019	Peri- or postmenopausal women in 5 randomized trials (6 trials, 779 women, reviewed)
Hot flush frequency in equol non-producers	Improved	160	Grade B · RCT, 2012	Equol non-producing postmenopausal Japanese women with at least 1 hot flush a day (126 completed)
Menopausal symptoms and mood	Improved	134	Grade C · RCT, 2009	Japanese women aged 40 to 59 (34.3% equol producers)
Hot flash frequency vs soy isoflavones (active comparator)	Mixed	102	Grade C · RCT, 2012	Postmenopausal women aged 45 to 65 with 5 or more hot flashes a day (US, per a 2015 review)
Hand osteoarthritis pain and function	Improved	102	Grade D · Open-label trial, 2025	Japanese women aged 45 to 60 with hand osteoarthritis who did not make equol
Crow's-feet wrinkles	Improved	101	Grade C · RCT, 2012	Equol non-producing postmenopausal Japanese women (pilot)
Menopausal symptoms with soy isoflavones, by equol producer status	Mixed	96	Grade C · RCT, 2008	Healthy menopausal women, grouped as equol producers or non-producers after a week of isoflavones
Bone resorption and whole-body bone density	Improved	93	Grade C · RCT, 2011	Non-equol-producing postmenopausal Japanese women (pilot)
Bone turnover markers and whole-body bone density (with resveratrol)	Improved	60	Grade C · RCT, 2023	Healthy postmenopausal women (Italy); equol producer status not tested
Climacteric symptoms, skin AGEs and visceral fat	Improved	57	Grade C · RCT, 2021	Postmenopausal Japanese women, mean age 56 (single centre)
HbA1c, LDL cholesterol and arterial stiffness in overweight adults	Improved	54	Grade C · Crossover RCT, 2013	Overweight or obese Japanese outpatients (BMI 25 or more; 67.9% equol non-producers)

Every graded row

11 rows

Form tested

Showing 11 of 11 outcomes. Human trials only.

Grade BHot flushes in postmenopausal women (pooled)Hot flushesLower hot flush scoresMeta-analysis · 5 studies
n 728 · 2019

Improved Equol significantly lowered hot flush scores overall, with a generally low risk of bias; two of the five pooled trials found no significant benefit and three did.

Design: Meta-analysis, 5 studies, n = 728, 2019
Population: Peri- or postmenopausal women in 5 randomized trials (6 trials, 779 women, reviewed)
Form: S-equol supplements, or soy isoflavones in equol producers
Dose: As given in each trial
Duration: Varied by trial
Source: Reference 4 · PubMed 30592686 (opens PubMed)

Grade BHot flush frequency in equol non-producersHot flushes−58.7% vs −34.5% hot flushesRCT
n 160 · 2012

Improved Hot flushes fell by 1.9 a day (−58.7%) with S-equol vs 1.0 a day (−34.5%) with placebo (p = 0.009); hot flush severity and neck or shoulder stiffness also fell more. No serious adverse effects or changes in clinical parameters.

Design: RCT, n = 160, 2012
Population: Equol non-producing postmenopausal Japanese women with at least 1 hot flush a day (126 completed)
Form: Natural S-equol supplement vs placebo
Dose: 10 mg/day
Duration: 12 weeks
Source: Reference 5 · PubMed 21992596 (opens PubMed)

Grade CMenopausal symptoms and moodMoodLower depression and fatigue scoresRCT
n 134 · 2009

Improved With 10 mg three times a day, depression scores fell versus placebo, as did tension-anxiety, depression-dejection and fatigue, while vigour rose. Equol non-producers after menopause improved from baseline on all symptom scores except depression. One woman had a systemic rash.

Design: RCT, n = 134, 2009
Population: Japanese women aged 40 to 59 (34.3% equol producers)
Form: S-equol supplement vs placebo
Dose: 10 mg once or three times a day
Duration: 12 weeks
Source: Reference 8 · PubMed 19131846 (opens PubMed)

Grade CHot flash frequency vs soy isoflavones (active comparator)Hot flushesSimilar at week 8; 40 mg better cumulativelyRCT
n 102 · 2012

Mixed At week 8 hot flash frequency fell similarly in all groups. Over the whole 8 weeks, 40 mg/day reduced hot flashes more than isoflavones (p = 0.021), and 10 and 20 mg/day improved muscle and joint pain more than isoflavones.

Design: RCT, n = 102, 2012
Population: Postmenopausal women aged 45 to 65 with 5 or more hot flashes a day (US, per a 2015 review)
Form: S-equol (SE5-OH) 10, 20 or 40 mg/day vs soy isoflavones
Dose: 10, 20 or 40 mg/day
Duration: 8 weeks
Source: Reference 6 · PubMed 22409590 (opens PubMed)

Grade CCrow's-feet wrinklesSkinSmaller wrinkle areaRCT
n 101 · 2012

Improved Wrinkle area fell significantly with both doses compared with placebo, and wrinkle depth with 30 mg/day. Hydration, water loss and elasticity did not change, and hormone and gynaecological checks were normal.

Design: RCT, n = 101, 2012
Population: Equol non-producing postmenopausal Japanese women (pilot)
Form: Natural S-equol 10 or 30 mg/day vs placebo
Dose: 10 or 30 mg/day
Duration: 12 weeks
Source: Reference 11 · PubMed 21934634 (opens PubMed)

Grade CMenopausal symptoms with soy isoflavones, by equol producer statusHot flushesBenefit in producers onlyRCT
n 96 · 2008

Mixed Hot flashes and sweating improved at 3 months, and total symptoms at 6 months, only in women who produced equol; non-producers did not differ from placebo.

Design: RCT, n = 96, 2008
Population: Healthy menopausal women, grouped as equol producers or non-producers after a week of isoflavones
Form: Soy isoflavones 135 mg/day vs placebo (not an equol supplement)
Dose: 135 mg/day isoflavones
Duration: 6 months
Source: Reference 12 · PubMed 18395723 (opens PubMed)

Grade CBone resorption and whole-body bone densityBone−23.94% vs −2.87% bone resorption markerRCT
n 93 · 2011

Improved With 10 mg/day, urinary deoxypyridinoline, a marker of bone breakdown, fell 23.94% vs 2.87% with placebo (P = 0.020), and whole-body bone density did not fall. Sex and thyroid hormones did not differ between groups.

Design: RCT, n = 93, 2011
Population: Non-equol-producing postmenopausal Japanese women (pilot)
Form: Natural S-equol supplement 2, 6 or 10 mg/day vs placebo
Dose: 2, 6 or 10 mg/day
Duration: 12 months
Source: Reference 7 · PubMed 21252728 (opens PubMed)

Grade CBone turnover markers and whole-body bone density (with resveratrol)BoneBetter bone markers; higher whole-body BMDRCT
n 60 · 2023

Improved Deoxypyridinoline, osteocalcin and bone-specific alkaline phosphatase improved versus placebo (p < 0.0001 for all); TRACP-5b did not change significantly (p = 0.051). Whole-body bone density rose versus placebo (p = 0.022).

Design: RCT, n = 60, 2023
Population: Healthy postmenopausal women (Italy); equol producer status not tested
Form: 200 mg fermented soy supplying 10 mg equol, plus 25 mg resveratrol, vs placebo
Dose: 10 mg equol plus 25 mg resveratrol once daily
Duration: 12 months
Source: Reference 16 · PubMed 37569440 (opens PubMed)

Grade CClimacteric symptoms, skin AGEs and visceral fatHot flushes81% vs 53% improvedRCT
n 57 · 2021

Improved Climacteric symptoms improved in 81% with equol vs 53% with control (p = 0.045). Metabolic and ageing biomarkers did not improve overall; skin autofluorescence and visceral fat improved in some subgroups, mainly equol producers.

Design: RCT, n = 57, 2021
Population: Postmenopausal Japanese women, mean age 56 (single centre)
Form: Equol-containing supplement vs control
Dose: Daily supplement (amount not stated in the abstract)
Duration: 3 months
Source: Reference 9 · PubMed 34506596 (opens PubMed)

Grade CHbA1c, LDL cholesterol and arterial stiffness in overweight adultsMetabolicLower HbA1c, LDL-C and CAVICrossover RCT
n 54 · 2013

Improved Compared with placebo, S-equol significantly lowered HbA1c, LDL cholesterol and the cardio-ankle vascular index, with larger effects in women who were equol non-producers.

Design: Crossover RCT, n = 54, 2013
Population: Overweight or obese Japanese outpatients (BMI 25 or more; 67.9% equol non-producers)
Form: Natural S-equol tablets vs placebo (crossover, no washout)
Dose: 10 mg/day
Duration: 12 weeks per period
Source: Reference 15 · PubMed 22469418 (opens PubMed)

Grade DHand osteoarthritis pain and functionJoint pain−34.0 mm pain on movementOpen-label trial
n 102 · 2025

Improved Pain on movement fell by 34.0 mm on a visual analogue scale and arm, shoulder and hand disability (DASH) scores fell by 6.6 points from baseline (both p < 0.001); improvement appeared within 1 to 3 months.

Design: Open-label trial, n = 102, 2025
Population: Japanese women aged 45 to 60 with hand osteoarthritis who did not make equol
Form: Natural S-equol supplement, no control group
Dose: 10 mg/day (two 2.5 mg tablets twice daily)
Duration: 12 weeks
Source: Reference 18 · PubMed 40666269 (opens PubMed)

What the numbers add up to

Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.

What the placebo did

In the largest trial, hot flushes fell 34.5% on placebo and 58.7% on S-equol, so about 24 percentage points of the fall belong to S-equol.⁵

How many people make equol

In the trials, 34.3% of Japanese women aged 40 to 59 and 3 of 12 postmenopausal women (25%) in a pharmacokinetic study were producers, in line with the 50% Asian and 25% non-Asian figures in a 2015 review.^8,10,13

Studied doses

Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.

Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.

Doses studied in human trials

Doses studied in human trials ranged from 2 mg a day (bone pilot) to 40 mg a day (US hot flash pilot), with 10 mg a day used in most trials for 8 weeks to 1 year; one trial gave 10 mg three times a day. A 2015 review notes the 7- to 10-hour half-life, which is why some trials split the dose. These are research amounts, not product directions.^{7,6,5,8,13,10}

When trials measured an effect

4 outcomes

How long trials ran before effects were measured
Outcome	Measured at	Basis
Hot flushes	Measured at 8 to 12 weeks	Randomized trials in Japanese and US women^5,6
Bone resorption marker	Measured at 12 months	Pilot placebo-controlled trial⁷
Hand osteoarthritis pain	Within 1 to 3 months	Single-arm 12-week pilot in 102 perimenopausal women¹⁸
Blood S-equol after a dose	Half-life about 8 hours	Pharmacokinetic study in 12 postmenopausal women¹⁰

Interactions and safety

Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.

What Equol meets

1 cited row

Medicines 1

Equol1 medicine · 0 supplements

Supplements and foods 0

No supplement rows in our sources.

Measured in a human study

Interactions

1 agent

Published interactions, grouped by kind
Agent	What the source says	Evidence
Medicines1
Breast cancer hormone therapye.g. anastrozole, letrozole, exemestane, tamoxifen	In 24 healthy postmenopausal women (6 per drug), an S-equol supplement at 10 mg/day for 7 days did not significantly change blood exposure (AUC) to any of the four drugs. Two authors were employees of the supplement's maker.¹⁷	PK study

Check with what you take

Kept on this device only

Add what you take. We list every interaction our evidence profiles cite between Equol and your picks, and between your picks.

Add a supplement or medicine

Most cited:

Add a supplement or medicine you take to check it against Equol.

Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.

Who should be careful

4 groups

Hormone-sensitive conditions: S-equol binds estrogen receptor beta. Trials checked hormones, endometrium and mammograms over 12 weeks to 1 year without finding problems, and a 2025 study found it did not significantly change blood levels of anastrozole, letrozole, exemestane or tamoxifen. None of the trials here reported on people with a history of hormone-sensitive cancer, who should ask their oncologist first.^10,11,7,17
Pregnancy and breastfeeding: NCCIH says soy may be unsafe in pregnancy in amounts greater than those commonly found in foods, and little is known about such amounts while breastfeeding. LactMed has no equol entry, and the trials enrolled peri- and postmenopausal women and overweight adults; we found no data on S-equol supplements in pregnancy or breastfeeding.^19,4,15
Soy allergy: S-equol supplements are made by fermenting soy germ. NCCIH notes that some people are allergic to soy and that soy must be declared on US supplement labels; the hand osteoarthritis trial excluded people with soy allergy.^19,10,18
People choosing a hot flash treatment: The Menopause Society's 2023 statement lists equol as not recommended and names hormone therapy as the most effective treatment, with several recommended nonhormone options.²

How to read the label

What to check on the Supplement Facts panel.

How to read the label

2 checks

S-equol, not isoflavones

An S-equol product lists milligrams of S-equol (10 mg a day in most trials). A soy isoflavone product lists isoflavones, which become equol only in people whose gut bacteria can make it.^5,12

Producer status

Most trials enrolled women who could not make equol, identified by testing urine after a soy challenge.^5,10

Have the bottle? Photograph its Supplement Facts panel and see each line, equol (s-equol) included, beside the doses and forms the trials used in Label X-Ray.

Frequently asked questions

Short answers to common questions; the numbers link to the sources below.

Common questions

8 answers

Does S-equol help hot flashes?

In trials, mostly yes: 10 mg a day cut hot flushes by 58.7% vs 34.5% with placebo in 160 Japanese women, and a 2019 meta-analysis of 5 trials found a benefit. The Menopause Society's 2023 statement still lists equol as not recommended because the evidence is limited or inconsistent.^5,4,2

Do I need equol if I already eat soy?

Only producers make equol from soy. In a 6-month isoflavone trial, symptoms improved only in women who produced equol, which is why most S-equol trials enrolled non-producers.^12,5

Is S-equol a hormone?

No, but it acts on estrogen receptors: it binds estrogen receptor beta selectively. Trials did not find changes in blood sex hormones.^10,7

Is S-equol safe?

Trials of up to 1 year reported no serious adverse effects and no changes in sex or thyroid hormones, endometrium or mammograms; one woman had a rash at 30 mg a day. A 2015 review called the limited safety data reassuring.^7,11,8,13

Can I take S-equol if I am allergic to soy?

S-equol supplements are made by fermenting soy germ, and NCCIH notes some people are allergic to soy. One equol trial excluded people with soy allergy, so anyone with a soy allergy should check with a clinician first.^10,19,18

Does S-equol interact with breast cancer drugs?

In a 2025 study of 24 postmenopausal women (6 per drug), 10 mg a day of S-equol for 7 days did not significantly change blood levels of anastrozole, letrozole, exemestane or tamoxifen. That study did not test whether it is safe after hormone-sensitive cancer, so ask an oncologist first.¹⁷

What is an equol producer?

Someone whose gut bacteria convert the soy isoflavone daidzein into S-equol. A 2015 review puts this at about 50% of Asians and 25% of non-Asians.¹³

Why does the Menopause Society not recommend equol?

Its 2023 nonhormone position statement rated the evidence for soy foods, soy extracts and equol as limited or inconsistent (Level II). Most trials were small, short and in Japanese women, for whom hot flashes are a minor complaint, as a 2015 review noted.^2,13

Sources

18 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.

Sources cited on this page

18 sources

1PubChem compound summary: (S)-equol (CID 91469)Database National Library of Medicine, 2026 · pubchem.ncbi.nlm.nih.gov
2The 2023 nonhormone therapy position statement of The North American Menopause Society.Guideline Menopause, 2023 · PMID 37252752
4Equol Decreases Hot Flashes in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.Meta-analysis J Med Food, 2019 · PMID 30592686
5A natural S-equol supplement alleviates hot flushes and other menopausal symptoms in equol nonproducing postmenopausal Japanese women.RCT J Womens Health (Larchmt), 2012 · PMID 21992596
6A pilot study on the effects of S-equol compared to soy isoflavones on menopausal hot flash frequency.RCT J Womens Health (Larchmt), 2012 · PMID 22409590
7Natural S-equol decreases bone resorption in postmenopausal, non-equol-producing Japanese women: a pilot randomized, placebo-controlled trial.RCT Menopause, 2011 · PMID 21252728
8New equol supplement for relieving menopausal symptoms: randomized, placebo-controlled trial of Japanese women.RCT Menopause, 2009 · PMID 19131846
9Effects of an equol-containing supplement on advanced glycation end products, visceral fat and climacteric symptoms in postmenopausal women: A randomized controlled trial.RCT PLoS One, 2021 · PMID 34506596
10The pharmacokinetics of S-(-)equol administered as SE5-OH tablets to healthy postmenopausal women.PK study J Nutr, 2009 · PMID 19776178
11The effects of natural S-equol supplementation on skin aging in postmenopausal women: a pilot randomized placebo-controlled trial.RCT Menopause, 2012 · PMID 21934634
12Effect of intestinal production of equol on menopausal symptoms in women treated with soy isoflavones.RCT Int J Gynaecol Obstet, 2008 · PMID 18395723
13S-equol: a potential nonhormonal agent for menopause-related symptom relief.Review J Womens Health (Larchmt), 2015 · PMID 25692726
14Acute and subchronic toxicity and genotoxicity of SE5-OH, an equol-rich product produced by Lactococcus garvieae.Animal study Food Chem Toxicol, 2008 · PMID 18554770
15Effects of natural S-equol supplements on overweight or obesity and metabolic syndrome in the Japanese, based on sex and equol status.Crossover RCT Clin Endocrinol (Oxf), 2013 · PMID 22469418
16Equol and Resveratrol Improve Bone Turnover Biomarkers in Postmenopausal Women: A Clinical Trial.RCT Int J Mol Sci, 2023 · PMID 37569440
17Lack of effects of S-equol-containing supplement on the pharmacokinetics of oral hormone therapy drugs for breast cancer.PK study Cancer Chemother Pharmacol, 2025 · PMID 41359041
18Effects of Equol on Hand Osteoarthritis in Perimenopausal Women: A Pilot Study.Open-label trial Cureus, 2025 · PMID 40666269
19Soy: Usefulness and SafetyFact sheet National Center for Complementary and Integrative Health (NCCIH), 2025 · nccih.nih.gov

What changed

Every dated change to this page: what changed, who made it and why.

Change log

2 entries

Dated changes to this page
Date	Change	Who and why
Oct 21, 2026key facts, evidence, interactions, who should avoid, time to effect, FAQ, questions, related	Added a 2025 pharmacokinetic study showing S-equol 10 mg/day did not change blood levels of anastrozole, letrozole, exemestane or tamoxifen (first interaction row); a 12-month equol-plus-resveratrol bone trial (60 women, grade C, combination product); and a 12-week single-arm hand osteoarthritis pilot (102 women, grade D, maker-sponsored) with its time to effect. Pregnancy and breastfeeding now cite NCCIH's soy page (April 2025); added a soy allergy note. Trimmed the FAQ from 10 to 8 by removing items that repeat the page's own questions (bones, skin, mood, studied dose) and adding drug interactions and soy allergy; added page questions and goal-hub links. Searched PubMed for 2020–2026 equol meta-analyses and RCTs: no newer hot flush meta-analysis than 2019; a 2026 premenstrual symptoms RCT (PMID 42528239) has no abstract on PubMed and was not added. LactMed and LiverTox have no equol or soy isoflavone entry.	Writer: Kymata Health EditorialTrigger: A–Z audit against docs/supplements/AUDIT-STANDARD.md
Oct 19, 2026all	New page. Every PMID checked with NCBI E-utilities (esummary title, year and journal) and its abstract read with efetch; PubChem read on the date shown. The rat toxicology study is cited only for the production method in the mechanism section.	Writer: Kymata Health EditorialTrigger: new page

Supplement & Nutrient Encyclopedia. Educational information only; it is not medical advice and does not replace a clinician. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease. Statements about supplements have not been evaluated by the FDA.

Equol (S-equol)

Medicines 1

Supplements and foods 0

Breast cancer hormone therapy