What evidence did the FDA review on HRT

DISCLOSURE: Voshell's Pharmacy is a licensed compounding pharmacy that prepares and sells compounded medications by prescription. As a provider of competing products, our perspective may be influenced by our professional and commercial interests.

According to FDA.gov, the agency reviewed large, long-term clinical trials showing that hormone therapy may relieve menopause symptoms but may also slightly raise risks such as blood clots, stroke, and breast cancer depending on the formulation, dose, and a woman's health history. Compounded medications are not reviewed by FDA for safety or effectiveness before dispensing and are prepared by a licensed pharmacist only in response to a valid prescription for an individual patient. This page primarily discusses commercially available hormone therapy products.

What the FDA actually reviewed

According to FDA.gov, the agency bases its guidance mainly on two types of evidence: large randomized trials and supportive observational studies. Here is what that includes:

• Women's Health Initiative trials: According to the WHI, these were government-funded studies with tens of thousands of postmenopausal women. One trial tested estrogen plus progestin; another tested estrogen alone for women without a uterus. The FDA relies heavily on these because they were randomized, meaning women were assigned to receive hormones or placebo, which helps clarify cause and effect.
• Detailed safety outcomes: According to FDA.gov, these trials tracked heart attack, stroke, blood clots, breast cancer, colorectal cancer, bone fractures, and overall mortality. The FDA reviewed each of these outcomes separately and looked at how risks may change over time.
• Symptom relief data: According to FDA.gov, the agency reviewed evidence showing that estrogen, with or without progestin, may reduce hot flashes, night sweats, and vaginal dryness. These benefits appeared consistently across the reviewed trials.
• Dose and formulation studies: According to FDA-approved prescribing information, smaller FDA-submitted trials evaluated pills, patches, gels, sprays, and vaginal products. These helped determine the lowest effective doses and how the body absorbs each form.
• Endometrial protection studies: According to FDA.gov, for women with a uterus, the FDA reviewed trials showing that adding a progestin may prevent overgrowth of the uterine lining, which may reduce cancer risk.
• Post-marketing safety monitoring: According to FDA Drug Safety Communications, after approval, the FDA continues reviewing real-world reports and newer research to refine warnings, especially related to blood clots and rare side effects.

What this means in practical terms

• Symptoms may improve. According to FDA.gov, the evidence for relief of hot flashes and vaginal symptoms is consistent across reviewed trials.
• Risks depend on age and timing. According to NAMS, women who start hormone therapy before age 60 or within 10 years of menopause may have different risk profiles than older starters — a qualified prescriber can help evaluate individual circumstances.
• Lowest dose, shortest duration is advised. According to FDA-approved prescribing information, this guidance comes directly from the balance of benefit and risk observed in the reviewed trials.