Soy is a fascinating ingredients in anti-aging skin care products. Studies have shown that its a powerful antioxidant and help the growth of healthy new collagen. In addition, genistein, a chemical in soy, prevents melanin pigments from attaching to skin cells. This makes soy a great addition to sun protection and indeed soy is effective for preventing and reducing brown spots and freckles of sun damage. However, soy does not work nearly so well for melasma, those dark patches that usually appear on the cheeks and forehead. This type of hyperpigmentation appears to be fueled by estrogen and in fact genistein is a type of pseudo-estrogen. In theory soy might actually make melasma worse.
So to bottom line it, if you have been a sun baby and have lots of small freckles, soy enriched moisturizers could brighten your skin. If you have larger patches, especially if they developed after you’ve been on “the pill” and or had a baby, soy won’t be of that much help.
One final thought. Some doctors are concerned that the estrogen-like compounds in soy could increase risk of breast and ovarian cancers. They have recommended limiting soy intake in foods and are now increasing that advice to include soy enriched skin care products. If you or your family have a history of breast or ovarian cancer, you might be wise to avoid soy based beauty aids.