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.

Understanding CYP1A1 and Estrogen Metabolism

Estrogen influences many body functions in both people assigned female and people assigned male at birth. The CYP1A1 gene makes an enzyme that helps convert estrogen into less active, protective forms. This conversion supports hormone balance and can lower risks tied to estrogen accumulation, such as prostate issues, gynecomastia, and reduced sperm quality. Variations in CYP1A1 can change how efficiently your body processes estrogen.

How CYP1A1 affects health

  • Efficient CYP1A1 activity favors conversion of estrogen into 2-hydroxy metabolites, which are generally considered protective.
  • Reduced CYP1A1 activity can shift estrogen metabolism toward more active forms, potentially contributing to hormone imbalance and related health concerns.
  • Lifestyle, diet, gut health, and environmental exposures interact with your genetic predisposition to influence overall estrogen metabolism.

Practical steps to support healthy estrogen metabolism

  • Diet: Eat cruciferous vegetables regularly — broccoli, cabbage, Brussels sprouts, cauliflower and kale — to provide compounds that support CYP1A1 activity.
  • Supplements: Consider supplements that support estrogen detoxification such as DIM (diindolylmethane) and calcium D-glucarate if appropriate for you. Discuss these with your healthcare provider before starting.
  • Avoid environmental estrogen mimics: Reduce exposure to BPA, phthalates, and other endocrine-disrupting chemicals by avoiding certain plastics, fragranced products, and unnecessary household chemicals.
  • Gut health: Maintain a diverse, fiber-rich diet to support microbiome balance and enterohepatic clearance of hormones.
  • Avoid tobacco and limit alcohol: Smoking and heavy alcohol use negatively affect hormone metabolism and overall detoxification pathways.
  • Monitoring: Regular hormone check-ups with your healthcare provider can help track levels and guide personalized interventions.

Genetic Interpretations

2 effect alleles — CC genotype (reduced CYP1A1 activity)

Carrying two copies of the effect allele for rs1048943 (CC) is associated with reduced CYP1A1 enzyme activity. This may lead to less efficient conversion of estrogen into protective 2-hydroxy metabolites. Possible implications include a higher predisposition to hormone-related concerns such as prostate issues, gynecomastia, and reduced sperm quality.

What you can do

  • Increase intake of cruciferous vegetables daily. Aim for a variety across meals to supply natural compounds that support enzyme activity.
  • Discuss with your healthcare provider whether targeted supplements such as DIM or calcium D-glucarate are appropriate for you.
  • Prioritize gut health: eat fiber-rich foods, fermented foods if tolerated, and avoid unnecessary antibiotics when possible.
  • Reduce exposure to endocrine disruptors by choosing glass or stainless steel for food storage, avoiding microwaving plastic, and selecting fragrance-free personal care products.
  • Stop smoking and limit alcohol to support liver detoxification pathways.
  • Consider periodic hormone testing if you have symptoms of imbalance or risk factors; work with your provider to interpret results.
1 effect allele — CT genotype (moderately reduced CYP1A1 activity)

Having one copy of the effect allele (CT) is linked to moderately reduced CYP1A1 function. Estrogen metabolism may be less efficient than in people with the non-effect genotype, and there may be a greater tendency to produce more active estrogen metabolites rather than protective ones.

What you can do

  • Make cruciferous vegetables a regular part of meals: roasted broccoli, stir-fried cabbage, or shredded Brussels sprouts in salads are easy options.
  • Talk with your healthcare provider about supplements such as DIM and calcium D-glucarate to support estrogen clearance.
  • Minimize exposure to BPA, phthalates and other common estrogen-like chemicals by choosing cleaner personal care products and reducing plastic use.
  • Maintain a healthy microbiome through a diet rich in diverse fibers, prebiotic foods, and fermented foods where appropriate.
  • Avoid smoking and keep alcohol consumption low to protect detoxification capacity.
  • Consider targeted testing for hormone levels if you have symptoms or are planning reproductive health interventions.
0 effect alleles — TT genotype (typical CYP1A1 activity)

With two copies of the non-effect allele (TT), your CYP1A1 enzyme is expected to function normally, efficiently converting estrogen into protective metabolites like 2-hydroxyestrone. This supports balanced hormone processing and typically indicates a lower genetic risk for estrogen accumulation-related issues.

What you can do

  • Continue a balanced diet that includes cruciferous vegetables to maintain healthy enzyme support.
  • Keep practicing lifestyle habits that preserve detoxification: avoid smoking, limit alcohol, and reduce exposure to endocrine-disrupting chemicals.
  • Support gut health with fiber and fermented foods as part of a varied diet.
  • Routine health check-ups and periodic hormone monitoring when clinically indicated remain good preventive practices.

Diet, Supplement, and Lifestyle Recommendations — Practical Tips

Below are actionable, everyday choices to support estrogen metabolism regardless of genotype. Always discuss changes with your healthcare provider before beginning new supplements or major dietary shifts.

Diet

  • Aim for 1 to 2 servings of cruciferous vegetables daily for natural support of estrogen-clearing pathways.
  • Include high-fiber foods: whole grains, legumes, vegetables, and fruits to support gut elimination of hormones.
  • Eat antioxidant-rich foods such as berries, leafy greens, and nuts to support liver health.

Supplements (discuss with your provider)

  • DIM: Can support balanced estrogen metabolism in some individuals. Dose and suitability should be reviewed with your provider.
  • Calcium D-glucarate: May support glucuronidation and removal of estrogen metabolites.
  • General liver-supportive nutrients: adequate B vitamins and vitamin C, as advised by your clinician.

Lifestyle and environmental steps

  • Use glass or stainless steel for food storage and avoid heating food in plastic.
  • Choose fragrance-free and phthalate-free personal care products when possible.
  • Stop smoking and moderate alcohol intake to protect metabolic enzymes and liver function.
  • Prioritize sleep, regular physical activity, and stress management to support overall hormone balance.

When to talk with your healthcare provider

  • If you have symptoms suggestive of hormone imbalance such as breast or chest tissue changes, changes in sexual or reproductive function, unexplained weight changes, or persistent fatigue.
  • If you are planning fertility treatments, prostate health monitoring, or hormone therapy.
  • Before starting supplements like DIM or calcium D-glucarate, or if you take medications that affect hormone metabolism.

PlexusDx does not provide medical advice. This information is educational and describes genetic predispositions only. Always consult your healthcare provider to interpret genetic results, discuss testing and treatment options, and decide on personalized care based on your health history and current medications.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report:

Frequently Asked Questions About Estrogen and CYP1A1 rs1048943

What does CYP1A1 rs1048943 mean for estrogen metabolism in my body?

CYP1A1 helps convert estrogen into less active, protective 2-hydroxy metabolites. Your rs1048943 genotype (TT, CT, or CC) can influence how efficiently this conversion happens, which may affect the balance between more protective versus more active estrogen metabolites. Variations can therefore shift genetic predisposition toward hormone imbalance-related concerns.

How can I support healthy estrogen metabolism if my CYP1A1 activity is reduced?

If you carry the effect allele (CT or CC), you may benefit from consistent lifestyle support for hormone detoxification pathways. Practical options include eating cruciferous vegetables regularly, maintaining a diverse fiber-rich gut diet, limiting exposure to endocrine disruptors (such as BPA and phthalates), and avoiding tobacco while moderating alcohol. Depending on your situation, ask your healthcare provider whether supplements like DIM or calcium D-glucarate are appropriate.

When should I talk to a healthcare provider about CYP1A1-related estrogen concerns?

Talk with your healthcare provider if you have symptoms that could suggest hormone imbalance (such as breast/chest tissue changes, changes in reproductive function, unexplained weight change, or persistent fatigue), if you’re planning fertility treatments or hormone therapy, or if you want to start supplements affecting estrogen metabolism (including DIM or calcium D-glucarate). Your clinician may also recommend hormone check-ups to help guide personalized next steps.

What tests can help me learn more about Estrogen and CYP1A1 rs1048943?

The Hormone, Thyroid, and Reproductive Health Genetic Test delivers over 85 personalized genetic insights through a comprehensive Hormone & Fertility Genetic Report, explaining inherited tendencies related to hormonal balance, reproductive function, and endocrine signaling. The Mens Hormone and Fertility Health Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

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.