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Secoisolariciresinol Diglucoside

Secoisolariciresinol Diglucoside

What the trials found

Secoisolariciresinol diglucoside has not been shown to improve ovulation signals in humans; evidence across hormone-related outcomes remains insufficient to establish a reliable benefit.

  • 2 papers
  • 1 of 5 outcomes

Median effective dose, most-studied outcomes

Full protocol, 1 outcomes

What secoisolariciresinol diglucoside actually does

Outcome Effect Evidence Dose Time Rank
Early research 1
Support fertility hormone levels Not enough research Reproductive hormones help regulate ovulation, menstrual cycles, and the chance of pregnancy.
trivial 		1 RCT 1 papers · n=149 50 mg 52 wk —

Effect tiers come from native-unit MCID where available, Cohen's d otherwise.

Protocol

Dose, timing & forms

How much

The only consumer-relevant hormone protocol reviewed used 50 mg daily of oral SDG over a long period. It did not show a statistically clear improvement in estrogen-related outcomes, so there is no evidence-based dose target for hormone support.2

When and how long

The available research tests SDG as a daily habit, not an occasional supplement. No trial evidence establishes a best time of day, a need to split the dose, or a meaningful advantage to taking it with or without food.2

Forms & standardisation

Look for a product that clearly names secoisolariciresinol diglucoside or SDG and states the amount per serving. Do not assume that a flaxseed product delivers the same amount of SDG as a purified extract, since whole flaxseed contains a changing mix of fiber, oils, and lignans.1

Studied range, by outcome

Outcome Studied range Median effective Duration Evidence
Support healthy estrogen function 50 mg — 52 wk 1 paper
In context

What this is and how it works

  • One study (n=149) assessed ovulation signals, but reported no clear direction for the measured endpoints.2
  • Two papers reviewed here span five outcomes, with evidence concentrated in one early ovulation study.
  • Human findings remain too limited to confirm effects on estrogen or progesterone patterns.2

Secoisolariciresinol diglucoside, or SDG, is a lignan, a naturally occurring plant compound concentrated in flaxseed. After you consume it, certain gut microbes remove its sugar groups and turn it into enterodiol and enterolactone, compounds with weak estrogen-like activity.1

Think of SDG as a locked kit that reaches the colon before local microbes assemble the active pieces. Those resulting lignans can dock weakly at estrogen receptors, more like a dimmer switch than a full light switch, but human hormone results remain too thin to show a useful real-world effect.12

Bottom line

SDG makes the most sense for people who are specifically interested in flaxseed lignans and accept that the human evidence is still early. It is not a proven way to shift estrogen or progesterone patterns, and anyone managing a hormone-sensitive condition should discuss supplements with a qualified clinician first.2

Frequently asked

Common questions

What is secoisolariciresinol diglucoside?

Secoisolariciresinol diglucoside, usually called SDG, is a plant compound found most notably in flaxseed. Gut microbes convert it into related compounds called enterodiol and enterolactone, which can interact weakly with estrogen signaling.1

Does SDG support estrogen balance?

There is not enough human research to say that it does. The reviewed hormone study used a 50 mg daily oral protocol but found no statistically clear effect, so SDG is not a reliable choice for changing estrogen status.2

Is SDG the same as flaxseed?

No. SDG is one lignan found in flaxseed, while ground flaxseed also provides fiber, fats, protein, and many other plant compounds. A purified SDG supplement does not reproduce the full food.

Sources

Sources

  1. 1. Secoisolariciresinol diglucoside
  2. 2. PubMed records on secoisolariciresinol diglucoside supplementation and hormone outcomes

Generated August 27, 2026

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