Red clover (RC) contains phytoestrogens (i.e., isoflavones: formononetin, biochanin A, genistein, and daidzein), which bind to the estrogen receptors and can elicit a weak agonist, antagonist, or partial agonist antagonist response. The effect depends on the compound and the target tissue. The isoflavones are activated when the glucose residue is removed by the bacterial enzymes in the gastrointestinal flora. Thus, the bioavailability of phytoestrogens is particularly dependent on the bacterial flora, which varies considerably between individuals [10]. Unlike soy, RC has a high content of both formononetin and biochanin A, and studies in ovariectomised rat models have shown that formononetin contributes to bone formation process by stimulation differentiation of osteoblasts [14, 15, 25].
By Ivar Leidus (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons