Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on hormones & fertility. Browse all Hormones & Fertility education

The ESR1 gene encodes estrogen receptor alpha, one of the two main proteins through which estrogen signals to cells throughout the body — in bone, blood vessels, the brain, the breast, and reproductive tissue. Two of its most-studied common variants, rs2234693 (historically called the PvuII polymorphism) and rs9340799 (the XbaI polymorphism), sit in the first intron of the gene and have been associated in research with a range of health tendencies.

These variants do not cause disease. They are common in the general population and describe subtle differences in how estrogen signaling is tuned. Here is what the research literature associates with them.

What ESR1 does

Estrogen receptor alpha is a transcription factor: when estrogen binds it, it switches specific genes on or off. Because estrogen influences so many systems, variation in the receptor's expression can ripple across bone density, cardiovascular function, and reproductive timing. rs2234693 and rs9340799 are thought to affect the level of receptor expression rather than the protein's structure.

Bone mineral density and osteoporosis

The most consistent research association for ESR1 variants is with bone mineral density. Estrogen is central to maintaining bone, and multiple studies have linked rs2234693 and rs9340799 genotypes to differences in bone density and fracture risk, particularly in postmenopausal women when estrogen levels fall. Effect sizes are modest and interact with calcium intake, activity, and other genes — this is a contributing factor, not a verdict.

Cardiovascular associations

Because estrogen influences blood-vessel function and lipid handling, ESR1 variation has been studied in relation to cardiovascular health. Some research has associated these variants with differences in HDL cholesterol and coronary outcomes, though findings vary across populations. The signal is real but nuanced, and cardiovascular risk is driven by many overlapping genetic and lifestyle factors.

Reproductive and hormonal timing

ESR1 variants have also been examined in relation to age at menarche and menopause, migraine, and estrogen-sensitive tissue biology. Because estrogen receptor alpha governs how tissues read estrogen, small differences in receptor expression can influence hormonal timing and sensitivity. As with the other associations, these are population-level tendencies, not individual predictions.

How to read a genetic association

An "association" means a genotype appears slightly more often in people with a given trait — it is not a diagnosis and not a guarantee. For common variants like rs2234693 and rs9340799, the influence of any single genotype is small and blends with dozens of other genes and your environment. This is exactly why pathway-level context, rather than single-gene fortune-telling, is the useful frame.

The PlexusDx Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights, placing hormone-related variants like those in ESR1 within the broader pathways they influence. It describes your biology at the pathway level; it does not diagnose, treat, or predict any condition.

What to do with ESR1 insight

If you carry a genotype associated with lower bone density tendencies, that is useful context for a conversation about bone health, weight-bearing activity, and nutrition with a qualified provider. Genetic insight is a starting point for informed discussion — not a directive to act on your own.

Frequently Asked Questions

What are rs2234693 and rs9340799?

They are two common variants in the ESR1 gene, which encodes estrogen receptor alpha. Historically called the PvuII and XbaI polymorphisms, they sit in the gene's first intron and are thought to influence how much receptor is expressed. Research associates them with bone, cardiovascular, and reproductive tendencies — not disease.

Do ESR1 variants mean I will get osteoporosis?

No. ESR1 variants are associated with modest differences in bone mineral density at the population level, but they do not determine whether any individual develops osteoporosis. Bone health depends on many genes plus estrogen status, nutrition, activity, and age. These variants are one contributing factor among many, best discussed with a provider.

Can a genetic test predict my disease risk from ESR1?

No. The Precision Peptide Genetic Test describes pathway-level tendencies in estrogen and hormone biology, not disease predictions or diagnoses. Single common variants carry small effects that blend with many others. Genetic insight offers context for informed conversations with a qualified healthcare provider, never a forecast of your medical future.

Are these variants rare or dangerous?

Neither. rs2234693 and rs9340799 are common in the general population and are not dangerous variants — they are normal human variation in how estrogen signaling is tuned. Their associations with health traits are subtle and statistical. Carrying them is not a medical condition and requires no treatment on its own.

Want to understand the genetic pathways behind your own biology? Take the Precision Peptide Genetic Test to see how your DNA influences the pathways discussed here — pathway-level insight, not a diagnosis. Test before you invest in any protocol.

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use, and it does not diagnose, treat, or prevent any disease. Consult a qualified healthcare provider before beginning any peptide protocol or making changes to your care.

This article is part of the PlexusDx Education Hub. Browse all Hormones & Fertility education

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.