Home Ingredients 7-Hydroxymatairesinol (HMR Lignan)
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7-Hydroxymatairesinol (HMR Lignan)

Evidence Level
Limited
6 Clinical Trials
5 Documented Benefits
2/5 Evidence Score

7-Hydroxymatairesinol, usually shortened to 7-HMR or HMR lignan, is a plant lignan concentrated in the knotwood of the Norway spruce and found in smaller amounts in whole grains. Gut bacteria convert it to the mammalian lignan enterolactone, the form measured in blood and thought to carry much of the activity. Like other lignans it is a phytoestrogen, meaning it can act weakly like the body's own estrogen. The human research is small. The main study gave a proprietary 7-HMR product to 22 postmenopausal women at 36 or 72 mg a day for 8 weeks and found that blood enterolactone rose and, in the higher-dose group, weekly hot flashes fell by about half, though it was single-blind with no placebo group. Most of the rest of the evidence is laboratory and animal work. HMR is distinct from flaxseed lignans, which come from a different compound but also produce enterolactone.

Studied Dose 36 or 72 mg a day of a proprietary 7-HMR product for 8 weeks in postmenopausal women. Blood enterolactone rose at both doses, while the fall in weekly hot flashes was reported only at 72 mg a day. These are the only human doses studied for this ingredient on its own.
Active Compound 7-hydroxymatairesinol (7-HMR), a plant lignan from the knotwood of Norway spruce (Picea abies), often supplied as its potassium acetate complex. Gut bacteria convert it to the mammalian lignan enterolactone.

Benefits

Enterolactone levels in postmenopausal women

Gut bacteria turn 7-HMR into enterolactone, a compound with weak estrogen-like activity. In a single-blind dose-comparison study of 22 postmenopausal women, 8 weeks of 36 or 72 mg a day raised blood 7-HMR and increased blood enterolactone by up to about 157 percent from baseline. There was no placebo group, so the rise reflects before-and-after measurements.

Supported by Trial 1, Trial 5

Hot flash frequency in a dose-comparison study

In the same study, women taking the higher dose of 72 mg a day reported about 50 percent fewer weekly hot flashes over 8 weeks, falling from roughly 28 to 14 per week. The study was single-blind, enrolled only 22 women and had no placebo arm, so the finding is preliminary and hot flashes often improve on placebo in menopause research.

Supported by Trial 1

Phytoestrogen activity in laboratory studies

In estrogen-sensitive MCF-7 cell studies, 7-HMR and its metabolite enterolactone acted weakly like the body's own estradiol, nudging more cells into the dividing phase but with far lower strength than estradiol, and the estrogen-receptor blocker tamoxifen reduced the effect. This is isolated-cell laboratory work, not a measured outcome in people.

Supported by Trial 3

Estrogen processing in a combination-supplement trial

In a 28-day randomized placebo-controlled trial in 96 pre- and postmenopausal women, a multi-ingredient formula containing HMR lignan and indole-3-carbinol raised a urinary marker of estrogen processing (2-hydroxyestrogen). Because several ingredients were combined, the change cannot be credited to HMR alone, and blood enterolactone did not rise significantly.

Supported by Trial 2

Antioxidant and inflammatory signals in human cell studies

In human monocyte-model (THP-1) cells and isolated white blood cells, 7-HMR lowered release of the inflammatory signal TNF-alpha and reduced production of reactive oxygen species in a dose-related way. These are laboratory findings in isolated cells and have not been confirmed as health outcomes in people.

Supported by Trial 4

Mechanism of action

1

Converted by gut bacteria to enterolactone

7-HMR is a precursor rather than the active form. Bacteria in the colon convert it to the mammalian lignans enterolactone and enterodiol. Enterolactone is what rises in the blood after taking HMR and is generally considered to carry most of the activity, which is why gut bacteria affect how much a person makes.

2

Weak estrogen-like activity (phytoestrogen)

Lignans such as HMR and enterolactone can bind estrogen receptors, but much more weakly than the body's own estradiol. This weak and mixed estrogen-like behavior is the proposed reason for effects on menopausal symptoms and the reason people with hormone-sensitive conditions are told to be cautious.

3

Antioxidant and anti-inflammatory signaling in the laboratory

In cell studies HMR scavenges reactive oxygen species and dampens inflammatory signals such as TNF-alpha and interleukin-8. These effects were seen in isolated human and animal cells and have not been shown as clinical outcomes in people.

Clinical trials

1
7-HMR Pharmacokinetics, Enterolactone and Hot Flashes: 22-Woman Dose-Comparison (no placebo)
PubMed

Single-blind, parallel, pharmacokinetic and dose-comparison study of a proprietary 7-HMR product (HMRlignan) at 36 or 72 mg a day for 8 weeks, with no placebo arm (Udani et al. 2013, J Am Coll Nutr)

22 postmenopausal women not receiving hormone replacement therapy, split between 36 mg a day and 72 mg a day.

Blood 7-HMR rose quickly after dosing. Blood enterolactone increased by up to about 157 percent in the low-dose group and 137 percent in the high-dose group from baseline. Mean weekly hot flashes fell about 50 percent, from 28.0 to 14.3 per week, in the 72 mg a day group. With no placebo group and only 22 women, these are before-and-after signals rather than controlled results. No significant safety issues were reported.

2
HMR Lignan Combination Formula and Estrogen Processing: 96-Woman RCT
PubMed

Randomized, double-blind, placebo-controlled trial of a multi-ingredient women's formula containing HMR lignan, indole-3-carbinol and other ingredients for 28 days (Laidlaw et al. 2010, Breast Cancer (Auckl))

96 pre- and postmenopausal women not taking hormonal contraceptives or supplements (47 pre-menopausal, 49 post-menopausal).

The combination supplement raised urinary 2-hydroxyestrogen and, in pre-menopausal women, the 2:16-alpha ratio, compared with placebo. Blood enterolactone did not rise significantly in either group. Because many ingredients were combined, the estrogen-processing change cannot be attributed to HMR by itself.

3
Estrogen-Like Activity of 7-HMR and Enterolactone in MCF-7 Cells (laboratory)
PubMed

Laboratory study of the estrogenic activity of 7-HMR and its metabolite enterolactone, compared with estradiol, in the human estrogen-sensitive MCF-7 cell line (Cosentino et al. 2007, Pharmacol Res)

Human MCF-7 breast cells in culture (not a human trial).

7-HMR and enterolactone acted weakly like estradiol, increasing the share of cells in the dividing phase and raising the Bcl-2/Bax ratio, but with lower potency and effect than estradiol. The estrogen-receptor blocker tamoxifen reduced the response, pointing to estrogen-receptor pathways. A cell-based finding, not a clinical outcome.

4
7-HMR Effects on Human Immune Cells (laboratory)
PubMed

Laboratory study of 7-HMR on human monocyte-model THP-1 cells and human polymorphonuclear leukocytes (Cosentino et al. 2010, Int Immunopharmacol)

Human THP-1 cells and isolated human white blood cells in culture (not a human trial).

7-HMR lowered release of the inflammatory signal TNF-alpha in THP-1 cells and reduced reactive oxygen species and interleukin-8 production in white blood cells in a dose-related way. These isolated-cell results have not been shown to reduce inflammation or oxidative stress in people.

5
13-Week Dietary Toxicity of HMRlignan in Rats (animal safety)
PubMed

Thirteen-week dietary toxicity study of the potassium acetate complex of 7-HMR (HMRlignan) at three dose levels in rats (Lina et al. 2005, Regul Toxicol Pharmacol)

Wistar rats fed HMRlignan at about 160, 640 or 2600 mg per kg body weight a day (not a human trial).

Blood 7-HMR and enterolactone rose with dose, with enterolactone the main metabolite. Plasma triglycerides and, at the top dose, cholesterol fell, matching other lignans. High doses lengthened the estrus cycle and lowered ovary weight, read as weak antiestrogen-like activity. The no-adverse-effect level was set at about 160 mg per kg a day.

6
7-HMR and Hormonal Responses in Live Animals (animal)
PubMed

In vivo study of plant lignan structure and hormonal responses, including whether lifelong 7-HMR exposure changed reproductive organ weights (Saarinen et al. 2005, J Steroid Biochem Mol Biol)

Rodent models exposed to 7-HMR or a related lignan over the lifespan (not a human trial).

7-HMR was converted to enterolactone. Unlike a closely related lignan, lifelong 7-HMR exposure did not raise uterine weight in females or ventral prostate weight in males at any age, which the authors read as a lack of a strong proliferative estrogen-like effect on these organs. An animal endocrine finding, not a human outcome.

Side effects and drug interactions

Common Potential side effects

In the only human study, 36 to 72 mg a day for 8 weeks was well tolerated with no significant safety issues reported, but it enrolled just 22 women for 8 weeks, so longer-term safety in people is not established.
7-HMR and enterolactone act weakly like estrogen, so people with a history of hormone-sensitive conditions such as breast or uterine problems should talk to a doctor before using concentrated lignan supplements.
In a 13-week rat study, high doses lengthened the estrus cycle and lowered ovary weight, read as weak antiestrogen-like activity; because of these hormonal effects and the lack of human data, it is best avoided in pregnancy and breastfeeding.
Lignans are plant compounds associated with plant fiber; mild digestive changes are possible when starting any new supplement.

Important Drug interactions

Hormone therapy (estrogen): because lignans act weakly like estrogen, effects could overlap or interfere; ask your doctor before combining.
Tamoxifen and aromatase inhibitors: 7-HMR showed estrogen-like activity in breast-cell studies and tamoxifen blocked it, so people taking these breast-cancer medicines should check with their oncologist before using lignan supplements.
No formal human drug-interaction studies of 7-HMR have been done; tell your prescriber about any supplement you take.

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Frequently asked questions about 7-Hydroxymatairesinol (HMR Lignan)

What is HMR lignan and where does it come from?

HMR lignan is 7-hydroxymatairesinol, a plant lignan concentrated in the knotwood of the Norway spruce and found in smaller amounts in whole grains. It is sold as a purified supplement, often as a potassium acetate complex. In the gut, bacteria convert it to enterolactone, the compound measured in the blood after taking it.

How is HMR lignan different from flaxseed lignans?

They are different compounds. Flaxseed's main lignan is secoisolariciresinol (SDG), while HMR is 7-hydroxymatairesinol from spruce. Both are converted by gut bacteria into enterolactone, so they share a metabolite, but they are separate ingredients with separate research and are covered in separate records.

Does it help with menopausal hot flashes?

One small 8-week study reported about half as many weekly hot flashes at 72 mg a day, but it had no placebo group and only 22 women, and hot flashes often ease on placebo. That makes the finding preliminary. Menopause is a normal life stage, and persistent symptoms are worth discussing with a clinician.

What dose has been studied?

The human study used 36 or 72 mg a day of a proprietary 7-HMR product for 8 weeks in postmenopausal women. Blood enterolactone rose at both doses, while the drop in weekly hot flashes was reported only at the higher 72 mg a day dose. These are the only human doses studied for the ingredient on its own.

Who should be cautious with HMR lignan?

Because lignans act weakly like estrogen, anyone with a history of hormone-sensitive conditions, or taking hormone therapy or breast-cancer medicines such as tamoxifen or aromatase inhibitors, should talk to their doctor first. There is not enough human data to support use during pregnancy or breastfeeding.

What is 7-Hydroxymatairesinol?

7-Hydroxymatairesinol, usually shortened to 7-HMR or HMR lignan, is a plant lignan concentrated in the knotwood of the Norway spruce and found in smaller amounts in whole grains. Gut bacteria convert it to the mammalian lignan enterolactone, the form measured in blood and thought to carry much of the activity.

What is 7-Hydroxymatairesinol used for?

7-Hydroxymatairesinol is researched primarily for Menopause Support and Women's Health. Gut bacteria turn 7-HMR into enterolactone, a compound with weak estrogen-like activity. In a single-blind dose-comparison study of 22 postmenopausal women, 8 weeks of 36 or 72 mg a day raised blood 7-HMR and increased blood enterolactone b…

What is the recommended dosage of 7-Hydroxymatairesinol?

The clinically studied dose is 36 or 72 mg a day of a proprietary 7-HMR product for 8 weeks in postmenopausal women. Blood enterolactone rose at both doses, while the fall in weekly hot flashes was reported only at 72 mg a day. Always follow the product label and check with a healthcare provider for personal advice.

Is 7-Hydroxymatairesinol safe, and does it have side effects?

For most healthy adults, 7-Hydroxymatairesinol is well tolerated at studied doses. Reported effects can include: In the only human study, 36 to 72 mg a day for 8 weeks was well tolerated with no significant safety issues reported, but it enrolled just 22 women for 8 weeks, so longer-term safety in people is not established. It may also interact with some medications. 7-Hydroxymatairesinol is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does 7-Hydroxymatairesinol interact with any medications?

Possible interactions include: Hormone therapy (estrogen): because lignans act weakly like estrogen, effects could overlap or interfere; ask your doctor before combining. Tamoxifen and aromatase inhibitors: 7-HMR showed estrogen-like activity in breast-cell studies and tamoxifen blocked it, so people taking th… If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for 7-Hydroxymatairesinol?

NutraSmarts rates the evidence for 7-Hydroxymatairesinol as Limited (2 out of 5). It is backed by 6 clinical trials and 8 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(8 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Udani JK, Brown DJ, Tan MO, Hardy M. Pharmacokinetics and bioavailability of plant lignan 7-hydroxymatairesinol and effects on serum enterolactone and clinical symptoms in postmenopausal women: a single-blinded, parallel, dose-comparison study. J Am Coll Nutr. 2013;32(6):428-35. doi: 10.1080/07315724.2013.849578.PubMedUsed to support: Single-blind, parallel dose-comparison study in 22 postmenopausal women taking a proprietary 7-HMR product at 36 or 72 mg a day for 8 weeks: blood 7-HMR rose quickly, blood enterolactone increased up to about 157 percent from baseline, and mean weekly hot flashes fell about 50 percent (28.0 to 14.3 per week) in the 72 mg a day group. No placebo arm; small; no significant safety issues reported.
  2. Laidlaw M, Cockerline CA, Sepkovic DW. Effects of a breast-health herbal formula supplement on estrogen metabolism in pre- and post-menopausal women not taking hormonal contraceptives or supplements: a randomized controlled trial. Breast Cancer (Auckl). 2010;4:85-95. doi: 10.4137/BCBCR.S6505.PubMedUsed to support: Randomized, double-blind, placebo-controlled 28-day trial in 96 pre- and postmenopausal women of a multi-ingredient formula containing HMR lignan and indole-3-carbinol: urinary 2-hydroxyestrogen rose versus placebo, but blood enterolactone did not rise significantly. Because many ingredients were combined, the estrogen-processing change cannot be attributed to HMR alone.
  3. Cosentino M, Marino F, Ferrari M, Rasini E, Bombelli R, Luini A, Legnaro M, Delle Canne MG, Luzzani M, Crema F, Paracchini S, Lecchini S. Estrogenic activity of 7-hydroxymatairesinol potassium acetate (HMR/lignan) from Norway spruce (Picea abies) knots and of its active metabolite enterolactone in MCF-7 cells. Pharmacol Res. 2007;56(2):140-7. doi: 10.1016/j.phrs.2007.05.001.PubMedUsed to support: Laboratory study in human estrogen-sensitive MCF-7 cells: 7-HMR and its metabolite enterolactone acted weakly like estradiol, increasing cells in the dividing phase and raising the Bcl-2/Bax ratio with lower potency than estradiol; tamoxifen reduced the effect, pointing to estrogen-receptor pathways. Cell-based, not a clinical outcome.
  4. Cosentino M, Marino F, Maio RC, Delle Canne MG, Luzzani M, Paracchini S, Lecchini S. Immunomodulatory activity of the lignan 7-hydroxymatairesinol potassium acetate (HMR/lignan) extracted from the heartwood of Norway spruce (Picea abies). Int Immunopharmacol. 2010;10(3):339-43. doi: 10.1016/j.intimp.2009.12.005.PubMedUsed to support: Laboratory study in human THP-1 monocyte-model cells and isolated white blood cells: 7-HMR lowered TNF-alpha release and reduced reactive oxygen species and interleukin-8 production in a dose-related way. Isolated-cell findings, not shown as health outcomes in people.
  5. Lina B, Korte H, Nyman L, Unkila M. A thirteen week dietary toxicity study with 7-hydroxymatairesinol potassium acetate (HMRlignan) in rats. Regul Toxicol Pharmacol. 2005;41(1):28-38. doi: 10.1016/j.yrtph.2004.09.001.PubMedUsed to support: Thirteen-week dietary toxicity study in Wistar rats at about 160, 640 or 2600 mg per kg a day: blood 7-HMR and enterolactone rose with dose; plasma triglycerides and, at the top dose, cholesterol fell; high doses lengthened the estrus cycle and lowered ovary weight (weak antiestrogen-like activity). No-adverse-effect level set at about 160 mg per kg a day.
  6. Saarinen NM, Penttinen PE, Smeds AI, Hurmerinta TT, Mäkelä SI. Structural determinants of plant lignans for growth of mammary tumors and hormonal responses in vivo. J Steroid Biochem Mol Biol. 2005;93(2-5):209-19. doi: 10.1016/j.jsbmb.2004.12.004.PubMedUsed to support: In vivo rodent study: 7-HMR was converted to enterolactone, and unlike a closely related lignan, lifelong 7-HMR exposure did not raise uterine weight in females or ventral prostate weight in males at any age, read as a lack of a strong proliferative estrogen-like effect on these organs. An animal endocrine finding.
  7. Biasiotto G, Zanella I, Predolini F, Archetti I, Cadei M, Monti E, Luzzani M, Pacchetti B, Mozzoni P, Andreoli R, De Palma G, Serana F, Smeds A, Di Lorenzo D. 7-Hydroxymatairesinol improves body weight, fat and sugar metabolism in C57BJ/6 mice on a high-fat diet. Br J Nutr. 2018;120(7):751-762. doi: 10.1017/S0007114518001824.PubMedUsed to support: Animal study in mice on a high-fat diet: oral 7-HMR (and a spruce extract) limited gains in body weight and fat mass, reduced liver fat, and improved insulin measures; the metabolites enterolactone and enterodiol reduced fat-cell differentiation in culture. Male mice and cell work, not evidence in people.
  8. Wolterbeek AP, Roberts A, Korte H, Unkila M, Waalkens-Berendsen DH. Prenatal developmental toxicity study with 7-hydroxymatairesinol potassium acetate (HMRlignan) in rats. Regul Toxicol Pharmacol. 2004;40(1):1-8. doi: 10.1016/j.yrtph.2004.04.001.PubMedUsed to support: Prenatal developmental toxicity study in pregnant rats fed HMRlignan throughout gestation: no effects on reproductive performance or on external, visceral or skeletal development of the fetuses, though about half of the top-dose dams ate poorly and lost weight. An animal study that informs reproductive safety; human pregnancy data are lacking.