Hydroxymatairesinol is a lignan compound derived primarily from the knots of Norway spruce (Picea abies). Lignans are a class of phytoestrogens—plant-derived compounds that can mimic or modulate the action of estrogen in the body. Several in vitro and animal studies have shown that hydroxymatairesinol can be converted by intestinal bacteria into enterolactone, a mammalian lignan with mild estrogenic activity. This has prompted interest in its potential for supporting estrogen-related body systems, particularly in peri- and postmenopausal women.

However, direct human evidence for any significant estrogenic or hormone-balancing effects is limited. Small clinical studies have investigated the safety of hydroxymatairesinol supplementation and its bioavailability, with some showing increased plasma enterolactone levels. Yet, there is little direct evidence from randomized controlled trials demonstrating concrete health benefits related to estrogen modulation, such as relief from menopausal symptoms or prevention of osteoporosis. Some epidemiological research suggests a potential association between higher lignan intake and reduced risk of hormone-dependent cancers, but causality and specific effects of hydroxymatairesinol remain unestablished.

In summary, while there is plausible mechanistic evidence and some supporting animal and in vitro data, robust clinical validation is lacking. Thus, the scientific evidence supporting hydroxymatairesinol for the estrogen body system is limited and should be considered preliminary.