Soy isoflavones are plant estrogens that can help with osteoporosis when consumed in moderation. However, not everyone should take them. Pregnant women, breastfeeding mothers, and individuals with hormone-sensitive cancers (like breast or uterine cancer) should avoid them. Additionally, soy isoflavones may affect thyroid function, so those with thyroid issues should be cautious. It's best to consult a doctor before starting any supplements.