Thyroid | TSHR (rs3783938)

TSHR and Thyroid Health: What Women Should Know

The thyroid gland plays a central role in metabolism, energy, and hormone balance. For women, healthy thyroid function is especially important for regular menstrual cycles, ovulation, and fertility. The TSHR gene encodes the thyroid-stimulating hormone receptor, which helps regulate thyroid hormone production and interacts with the immune system. Variants in TSHR can influence the risk of autoimmune thyroid disease, including Hashimoto’s thyroiditis, which can lead to hypothyroidism and downstream effects on energy, weight, hair, and reproductive health.

How TSHR Variation Can Affect Health

Changes in the TSHR gene can alter receptor function or immune recognition of the thyroid gland. When the immune system targets thyroid tissue, chronic inflammation may reduce thyroid hormone production. Low thyroid hormone levels can cause:

Fatigue and low energy
Weight gain or slowed metabolism
Irregular periods, anovulation, or reduced fertility
Cold intolerance, dry skin, hair thinning
Elevated cholesterol and mood changes

Symptoms to Watch For

Persistent fatigue not explained by sleep or stress
Unexplained weight gain or difficulty losing weight
Changes in menstrual cycle length or flow
Hair thinning, brittle nails, dry skin
Feeling cold more often than usual

Genetic Interpretation for rs3783938

TT genotype — 2 effect alleles

If you have the TT genotype for rs3783938, you carry two copies of the effect allele. This genotype is associated with an increased risk of developing Hashimoto’s thyroiditis, an autoimmune condition where the immune system attacks the thyroid gland. Over time this can lead to hypothyroidism and symptoms such as fatigue, weight gain, menstrual irregularities, hair changes, and fertility challenges.

Recommendations:

Discuss baseline thyroid testing with your healthcare provider: TSH, free T4, free T3, and thyroid peroxidase (TPO) and thyroglobulin antibodies.
Ensure adequate intake of selenium, iodine, vitamin D, zinc, iron, and vitamin A through diet or targeted supplements if recommended by your clinician.
Moderate intake of soy and large amounts of raw cruciferous vegetables if you develop thyroid dysfunction; cooking reduces goitrogenic activity.
Minimize gluten if you have or develop autoimmune thyroid disease and your provider advises testing for gluten sensitivity or celiac disease.
Reduce exposure to endocrine disruptors: avoid unnecessary plastics, choose personal care products free of known endocrine-disrupting chemicals, and filter drinking water when possible.
Prioritize sleep hygiene, stress management, and regular physical activity to support immune and hormonal balance.
Plan regular follow-up testing — frequency determined by your clinician and symptoms — to monitor thyroid status and antibodies.

CT genotype — 1 effect allele

If you have the CT genotype for rs3783938, you carry one copy of the effect allele. This genotype is associated with an increased risk of Hashimoto’s thyroiditis compared to the non-effect genotype, though the risk is typically lower than with two effect alleles. You may be more susceptible to autoimmune thyroid inflammation that can eventually affect thyroid hormone production and fertility-related processes.

Recommendations:

Consider baseline and periodic thyroid screening: TSH, free T4, and thyroid antibodies when indicated by symptoms or family history.
Support nutritional needs with foods rich in selenium (brazil nuts, seafood), iodine (iodized salt, seaweed in moderation), vitamin D (sunlight, fatty fish), zinc (meat, shellfish, legumes), iron (lean meats, leafy greens), and vitamin A (orange and green vegetables).
Limit very high consumption of raw cruciferous vegetables and large amounts of soy if thyroid symptoms appear.
Address lifestyle factors that influence autoimmunity: sufficient sleep, stress reduction, moderate exercise, and avoidance of smoking.
Reduce exposure to environmental endocrine disruptors in food packaging and personal care products.
Work with your provider on monitoring frequency and any needed interventions if antibody levels or thyroid function change.

CC genotype — 0 effect alleles

If you have the CC genotype for rs3783938, you carry two copies of the non-effect allele. This genotype is associated with typical thyroid-stimulating hormone receptor activity and a lower genetic predisposition for autoimmune thyroid conditions at this locus compared to individuals carrying the T allele. You are likely to have more stable thyroid regulation, which supports balanced metabolism, energy, and reproductive function.

Recommendations:

Maintain routine health care and consider periodic thyroid screening, especially if you experience symptoms or have a family history of thyroid disease.
Support thyroid health through a balanced diet that provides adequate iodine, selenium, zinc, iron, vitamin D, and vitamin A.
Practice good sleep hygiene, stress management, and regular exercise to support hormone balance and immune health.
Limit unnecessary exposure to endocrine-disrupting chemicals and consider evaluating supplements or medications with your provider if you pursue fertility treatments or have other health concerns.

Practical Diet and Supplement Guidance

Aim for nutrient-dense meals that support thyroid and reproductive health. Focus on whole foods and tailor supplements only after discussing with a healthcare provider and reviewing labs.

Selenium: Supports thyroid antioxidant defenses. Sources include brazil nuts, seafood, and eggs. Typical supplemental doses are individualized.
Iodine: Necessary for thyroid hormone synthesis. Use iodized salt in moderation and avoid excessive seaweed intake without provider guidance.
Vitamin D: Many people are low; adequate vitamin D supports immune regulation. Check 25(OH)D levels and supplement to reach target ranges if needed.
Zinc and Iron: Important for thyroid hormone production and reproductive health; correct deficiencies based on lab tests.
Vitamin A: Supports thyroid hormone action; obtain from food or safe supplement doses to avoid excess.
Avoid high-dose self-prescribed iodine, selenium, or other supplements without provider oversight, especially if you have or suspect autoimmune thyroid disease.

Lifestyle and Monitoring

Testing: Work with your provider to check TSH, free T4, free T3, and thyroid antibodies when symptoms arise or for baseline monitoring if you have increased genetic risk.
Sleep: Aim for consistent, restorative sleep to help immune and hormonal regulation.
Stress: Chronic stress can influence autoimmunity; incorporate stress-reduction practices such as mindfulness, gentle exercise, or therapy.
Endocrine disruptors: Reduce exposure by choosing glass or stainless steel for food storage, avoiding BPA-containing plastics, and selecting personal care products with simple ingredient lists.
Fertility planning: If you are trying to conceive and have thyroid symptoms or positive thyroid antibodies, discuss evaluation and optimization of thyroid function with your provider prior to conception.

When to Talk to Your Healthcare Provider

If you experience persistent fatigue, unexplained weight changes, menstrual irregularities, hair loss, or new cold intolerance.
If you have a family history of autoimmune thyroid disease or other autoimmune conditions.
Before starting any thyroid-targeted supplements or making major dietary changes, especially if pregnant, trying to conceive, or breastfeeding.
For personalized interpretation of genetic results alongside clinical labs and medical history.

PlexusDx provides genetic education and interpretations to help you understand predispositions. This information is not medical advice. Please consult your healthcare provider for personalized medical evaluation, diagnosis, and treatment decisions.