Are bioidentical hormones safe? Compounded HRT, pellets and approved body-identical options

Name: Are bioidentical hormones safe? Compounded HRT, pellets and approved body-identical options
Creator: MenoWoman

Bioidentical hormones are not the problem: approved estradiol and progesterone products are bioidentical and well tested. The safety worry is custom-mixed compounded hormones and pellets, which lack proof of safety, effectiveness or consistent dosing.

Researched by the MenoWoman team. Edited by Marcela Sat. Updated 7 November 2026. We may earn from links.

See a doctor promptly for any vaginal bleeding after menopause, especially if you use a progesterone cream or compounded product. Also seek care for a new breast lump, leg swelling, chest pain or sudden breathlessness, or new acne, facial hair or voice changes after pellets.

Bioidentical is not the same as compounded

"Bioidentical" means a hormone has the same chemical structure as the one your body makes. Approved estradiol and micronized progesterone meet this definition.^4,5 In the UK these are often called body identical HRT.

Approved body-identical estradiol comes as tablets, patches, gels and vaginal products. Progesterone comes as capsules.⁵ These products are tested for quality and safety and made to consistent doses.⁵

Compounded products are mixed by a pharmacist to a custom recipe. They are often sold as "natural", but even plant-based hormones are made in a lab.⁵ Compounded products are not FDA-approved, so their safety, effectiveness and quality cannot be checked in the same way.⁴

What expert bodies say

In 2020, the US National Academies of Sciences, Engineering, and Medicine (NASEM) found insufficient evidence for the clinical use of compounded bioidentical hormones. It said claims that they are safer or work better are not supported by good studies.¹

NASEM said prescribers should limit them to two cases. One is an allergy to an ingredient in an approved product. The other is a need for a form no approved product offers.¹

ACOG and The Menopause Society have both issued statements against compounded hormone therapy and favor FDA-approved products when available.⁴ The Australasian Menopause Society does not recommend compounded hormones in any form, including creams and lozenges.⁵

NASEM also said prescribers should explain the risks and give a clear reason when they prescribe a compounded product. It called for better tracking of how often these products are used and what harms they cause.¹

Safety concerns

Custom mixing lacks standards and oversight. This raises the risk of too much hormone, too little, or contamination.¹ One doctor reported seeing both underdosed and overdosed patients on compounded products.³

Too little progestogen is a particular worry. Progestogens protect the womb lining when estrogen is used, and cases of womb (endometrial) cancer have been linked to compounded products whose progestogen did not protect the lining.⁵

No peer-reviewed studies show that compounded creams or pellets are safer or more effective than approved products. Claims that they prevent dementia, extend life or lower breast cancer risk are unproven.²

Hormone pellets

Pellets are placed under the skin and dissolve over months. Compounded hormone pellets for women are not FDA-approved. They are designed to dissolve over time, not to be removed, which is a problem if side effects appear.⁴

In one US clinic study, pellet users had much higher peak estradiol and testosterone levels than women on approved therapy. Testosterone levels in pellet users were far above those seen on approved treatment.³ Another study reported side effects in 57.6% of pellet users versus 14.8% on approved products. These included mood swings, anxiety, acne, breast tenderness and abnormal bleeding.²

NASEM recommended that pellets be considered for the FDA's "difficult to compound" list.¹

Saliva hormone testing

Compounding clinics often use saliva tests to set doses. These tests are expensive, not standardized and not quality controlled, so they cannot reliably show hormone levels.⁵ Menopause is usually diagnosed from symptoms and age. See are at-home menopause tests accurate?

Compounded products also tend to cost more and are rarely covered by insurance.² Approved body-identical options are available on prescription in the US, UK, Australia and many other countries. For how regulated HRT works, and recent US label changes, see hormone therapy. A doctor can help you weigh options and decide on any changes.

HRT of any kind, compounded or approved, is not a contraceptive, and pregnancy is still possible in perimenopause. NICE advises that women in perimenopause are given information about contraception.⁶

What it is used for: evidence rated

Option	Evidence	What the research shows
Approved body-identical estradiol and progesterone	Strong evidence	Regulated, widely tested products made to consistent doses; favored by ACOG and The Menopause Society.^4,5
Menopause symptoms (compounded hormones)	Weak evidence	NASEM found insufficient evidence for clinical use; no good trials compare them with approved products.^1,2
Claims of being safer than approved HRT	No evidence	No peer-reviewed evidence shows compounded creams or pellets are safer or cause fewer side effects.²
Saliva testing to guide doses	No evidence	Saliva tests are not standardized or quality controlled and are unreliable.⁵

Ratings explained: how we rate. Always talk to a doctor or pharmacist before starting a medicine or supplement.