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The Clinical Thyroid Overview: Hormones, Labs, and Imbalances
- KhadiYah
- 8 hours ago
- 4 min read
Understanding thyroid function is non-negotiable for any serious herbal practitioner. This gland affects nearly every cell in the body and plays a central role in energy, metabolism, mood, menstrual cycles, fertility, and more.
These clinical notes compile essential knowledge on the thyroid’s structure, hormones, symptoms of imbalance, testing markers, and signs practitioners should be trained to spot. Use this as a foundational study guide, client intake companion, or protocol builder for both hypothyroid and hyperthyroid presentations.
Thyroid Gland Notes
General Thyroid Overview
Lies in the neck in front of the trachea, butterfly shape.
Produces hormones that help regulate metabolism and heart rate.
Spherical sacs = follicles; the walls of which produce:
T3 (triiodothyronine)
T4 (thyroxine)
It needs iodine to produce hormones and selenium to convert T4 to T3
Almost every cell in the body has receptors for TH.
Can store large quantities of hormone.
100-day supply of TH.
Produces calcitonin – inhibits the loss of calcium from bones into the blood.
T3 vs T4:
T4 = storage
T3 = active (shorter-acting but more potent)
Hormone Regulation Flow: Hypothalamus → TRH → Pituitary → TSH → Thyroid → TH (T3 + T4) → Targets metabolism, growth, and tissue effects.
TRH = Thyrotropin-releasing hormone from hypothalamus.
TSH = Thyroid-stimulating hormone from anterior pituitary.
Blood levels of TH feed back to the pituitary/hypothalamus to stimulate or inhibit activity.
Hypothyroidism
Dry skin
Feeling cold
Depression
Difficulty concentrating
Constipation
Brittle nails
Hair thinning
Weight gain
Loss of appetite
Extreme tiredness (sluggish)
Headache
Poor memory
Irregular periods
Infertility
Low interest in sex
Male: leaking from breast (when not nursing)
Muscle spasm
Shortness of breath
Slow healing
Frequent infections
Tingling in hands/feet
Muscular growth delays (kids)
Doctor should look for:
Delayed reflexes
Goiter
High cholesterol
Increased BP
Muscle weakness
Slowed pulse
TSH test
Drug interactions to note:
Lithium
Estrogens
Thyroid suppressors:
Cruciferous vegetables, low iodine, stress, inflammation, fluoride, some medications (lithium, SSRIs)
How it Presents: Hypothyroidism:
The heart muscle likely affected.
1/3 of patients suffering from depression are hypothyroid.
Enlargement from overstimulation (Hashimoto’s or goiter).
High TSH = growth of thyroid.
Trouble reaching sleep stage 3 and 4 (deepest).
Nails may have lines or grooves.
Puffy face.
Hair changes.
Menstrual periods become heavier and more frequent.
Anemia.
Muscle spasms or cramps due to metabolism changes.
Hyperthyroidism
Too much TH.
Symptoms:
Adrenaline rush
Hyperdefecation (stimulated digestion)
Sadness
Mania
Anxiety
Deep perspiration
Easy bruising
Enlarged thyroid gland (swollen thyromegaly)
Eye problems
Swollen fingers/toes
Nail growth becomes soft, easy to chip
Hair becomes thin, softer, finer, and grayer
Heart palpitations
Heat intolerance
Sweat more than usual
Irritability
Miscarriage risk
Testing & Lab Work
TSH derived from testing "normal people" who may have an underlying thyroid issue, "normal" looks different for everyone
Normal range of TSH: 0.4–4.0
Over 4 is hypothyroid
Below 0.4 is hyperthyroid
TSH is a delayed indicator
Tests:
Equilibrium dialysis free T4 = actual free T4 level (expensive, takes a while for the lab to complete; most useful for severely ill patients when free T4 test may not be accurate)
Free T4 = measures effective T4 level in the blood
The free thyroxine index = considered outdated, but gives a reasonable estimate of free T4
Total T4 may be misleading in pregnancy
Blood protein changes affect T4 levels (e.g. nephrotic syndrome, liver disease, some kidney diseases)
T3 can be useful to assess TH in thyrotoxicosis (but not actual T3 inside the cell)
Other notes:
No organ other than the thyroid makes thyroid hormone
Thyroglobulin levels are most important in follow-up of thyroid cancer patients
If removed thyroid gland or had nodular tumor, tracking thyroglobulin helps indicate residual thyroid cancer cell presence
Autoimmune & Antibodies
3 major thyroid antibodies:
TPO (thyroid peroxidase antibody): used to be called anti-microsomal antibodies. Attacks enzyme responsible for making thyroid hormone.
Antithyroglobulin antibody: present in 95% of people with Hashimoto’s
TSI (thyroid-stimulating immunoglobulin): associated with Graves' disease. Stimulates TSH receptors and causes overactivity.
Almost 1/4 women in N. America show high TPO antibodies.
High TPO also found in postpartum thyroiditis and miscarriage.
Pituitary gland is stimulated to make hormone by hypothalamus.
Metabolism & Function
Classic metabolism test:
Basal metabolic rate (BMR)
Thyroid gland uses:
20g of iodine each gram taken = 1% of the iodine available
From the chest: hyperthyroid patients typically take up more iodine.
Iodine
Daily Value = 150mcg
Sources:
Iodized salt
Lobster
Shrimp
Cooked oysters
Nori/seaweed
Breast milk
Functions:
Regulates energy production
Regulates body temperature
Breathing
Muscle tone
Metabolism
Bone development
Supplements: 7.5mg potassium iodide per tablet. (Some forms come in dosed salt or water.)
Studies show positive and improved effect in women (esp. thyroid cancer prevention).
Physical Signs
Skin yellowing (vitamin A disruption)
Stunted growth in children
Voice changes (swelling in vocal cords)
Moderate to severe hypothyroid patients should not drive
Puffy face
Pale complexion
Lips: swollen and purplish (poor circulation)
Eyebrows: thinning (esp. outer third)
Hair: dull, limp, lacks sheen
Skin: thick, dry, peeling, persistent pigmentation (esp. in creases)
Thyroid Hormone Processing
Processes involving TH (T3 and T4):
BMR: Increases basal rate by stimulating the conversion of fuel (glucose/fat) into energy in cells
Raises body temperature (calorigenesis)
Enhances cholesterol turnover
Increases carb/fat metabolism
Promotes glucose use for energy
Growth & Development:
Acts with growth hormone and insulin to promote normal development of nervous system (in fetal/infant)
Required for menstrual cycle regulation, ovulation, reproduction
Increases heart rate and contraction force of the heart
Enhances sensitivity of cardiovascular system to signals from sympathetic nervous system
Normal Thyroid Weight: 15–20g
Enlarged Gland: goiter
Diffuse = symmetrically enlarged
Nodular = 1 or more distinct lumps
Swallowing Check: when you swallow, the entire thyroid moves upward/downward.
Sources (Affiliate Links)
For Herbs for the Thyroid read this article here.
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