One of the biggest risks of bio-identical hormone therapy is that the drugs often have to be obtained through a compounding pharmacy and, therefore, have not been approved by the FDA. This means they have not been thoroughly tested or evaluated for safety and efficacy, according to the FDA.
As of May 2015, no long-term studies have been conducted on the safety of bio-identical hormones, reports the FDA. There are also concerns about misleading advertising on the part of the companies that sell or manufacture these hormones. Some of them claim that bio-identical hormones are safer than traditional hormone therapies. They also claim that bio-identical hormones can treat conditions such as Alzheimer's disease, heart disease and breast cancer, but this has not been proven. This misleading advertising may lead to unnecessary treatment.
The FDA is also concerned about the consistency of compounded products. They may be mixed with creams or binding agents that do not absorb properly, leading to a lower dose of the hormone. Some pharmacies create custom mixes based on a test of the patient's saliva, but this is not a reliable way to test hormone levels. They also often contain estriol, which is not approved by the FDA.
The other risks of bio-identical hormone therapy are the same as traditional hormone therapy, notes Everyday Health. These can include an increased risk of blood clots, stroke and certain cancers.