Women with damaged ovaries or who are post-menopausal don't produce sex hormones, which can lead to osteoporosis.
Though daily HRT helps, it can have side effects.
In a new method, Emmanuel Opara at Wake Forest University, North Carolina, and colleagues placed two types of hormone-producing cells from rat ovaries inside an algal capsule, then exposed it to chemicals from the pituitary gland that stimulate hormone production.
They found that the cells made sex hormones in the same proportions as healthy ovaries.
The team said that the hormone capsule would react more dynamically than HRT with fewer side effects.
These results appeared in print under the headline "Fake ovary replaces missing hormones" in Biomaterials.