Beneficial Supplements for Under-active Thyroid (Hypothyroidism)

A FullScript Article

Kayla Robinson

First described by Hakaru Hashimoto in 1912, Hashimoto’s thyroiditis is the most common cause of hypothyroidism (underactive thyroid gland) in developed countries, including the United States where it affects approximately 1 to 2% of the population. (4)(25) Although the condition can occur in both men and women at any age, it is at least ten times more common in women and most often diagnosed between the ages of 30 to 50 years old. (14)

What is Hashimoto’s thyroiditis?

Hashimoto’s thyroiditis, also known as Hashimoto’s disease, chronic lymphocytic thyroiditis, or autoimmune thyroiditis, is a progressive autoimmune disease resulting in damage to the thyroid gland and ultimately, hypothyroidism. (17) In individuals with Hashimoto’s, the body produces antithyroid antibodies that destroy cells of the thyroid gland resulting in decreased production of thyroid hormones. (7)(14)(17) Thyroid hormones play a key role in energy metabolism and regulation of several vital body functions, such as growth and development, heart rate, body weight, body temperature, and menstrual cycles. (4)

woman holding her neck

Hashimoto’s thyroiditis is a progressive autoimmune disease resulting in damage to the thyroid gland and ultimately, hypothyroidism.

Causes and risk factors

While the pathogenesis and the exact cause of Hashimoto’s thyroiditis are not fully understood, it is believed that the condition involves a combination of genetic susceptibility and environmental triggers. (17)(25) Research has identified the involvement of a number of possible genes, including those involved in the human leukocyte antigen (HLA) complex and in the regulation of immune and thyroid function. It has been suggested, however, that these genetic variations only account for a very small increase in the overall risk. (4)

Many other factors may contribute to an individual’s risk of developing Hashimoto’s, including:

  • Certain medications (e.g., IFN-α, IL-2)
  • Changes in sex hormones (particularly in women)
  • Chemical exposure (e.g., polyaromatic hydrocarbons or polyhalogenated biphenyls)
  • Excess consumption of iodine
  • Exposure to ionizing radiation
  • Gender (more common in women)
  • Having a close relative with Hashimoto’s
  • Infections (e.g, hepatitis C infection, parvovirus, rubella, herpes simplex virus, Epstein Barr virus, and human T-lymphotropic virus type 1, Toxoplasma gondii) (4)(29)(17)

Further, Hashimoto’s thyroiditis is commonly associated with other autoimmune conditions, including Addison’s disease, diabetes mellitus type 1 (T1DM), rheumatoid arthritis, systemic lupus erythematosus (SLE), autoimmune hepatitis, pernicious anemia, Sjögren’s syndrome, vitiligo, and multiple sclerosis. (4)(17)(25)

Signs and symptoms of thyroid issues

Hashimoto’s thyroiditis is typically diagnosed based on symptoms, a physical exam, and blood tests indicating elevated thyroid-stimulating hormone (TSH), low “free” thyroxine (T4), and increased anti-thyroid peroxidase (anti-TPO) antibodies (7)(14)

Signs and symptoms of Hashimoto’s, which develop and progress over time, include:

  • Cold intolerance
  • Constipation
  • Difficulty conceiving (women)
  • Difficulty concentrating or thinking
  • Difficult swallowing
  • Fatigue
  • Goiter (enlarged thyroid)
  • Hair loss
  • Heavy and/or irregular menstrual cycles (women)
  • Joint and/or muscle pain
  • Pale, puffy face
  • Slow heart rate
  • Thin, brittle hair and skin
  • Weight gain, difficulty losing weight (4)(7)

If left unaddressed, individuals with Hashimoto’s may develop several serious complications, including:

  • Birth defects (if mother has untreated hypothyroidism)
  • Decreased libido
  • Depression and slowed mental functioning
  • Enlarged heart or heart failure
  • Goiter, which may interfere with swallowing or breathing
  • Myxedema coma (7)

woman wrapped in a blanket looking at her laptop

Underactive thyroid symptoms include cold intolerance and fatigue.

Ingredients for underactive thyroid

The conventional treatment for Hashimoto’s thyroiditis typically involves hormone replacement therapy. (17) For example, levothyroxine is a medication commonly prescribed for thyroid hormone deficiency, including Hashimoto’s-related deficiency. (14) The following supplement ingredients, used on their own or in conjunction with other treatments, have been shown to induce beneficial effects on thyroid function.


An essential trace element, selenium is an important component of several selenoproteins, such as glutathione peroxidase, that participate in critical body functions, including DNA synthesis, reproduction, immune responses, and thyroid hormone metabolism. (18)(20)(24) As a result, selenium may play a role in a number of health conditions, such as cardiovascular disease, cancer, cognitive decline, and thyroid disease. (18)

Selenium is naturally present in a wide variety of dietary sources. Common animal sources include organ meats, beef, poultry, dairy, fish, and other seafood. Plant-based sources of selenium include nuts, particularly Brazil nuts, seeds, green vegetables, grains, and certain mushrooms. When choosing plant-based foods, it’s important to note that selenium content can vary significantly depending on the content of the soil in which these foods are grown. (18)(24)

A presence of anti-TPO antibodies can lead to inflammation and impaired thyroid function. Several studies have observed a decrease between 20% and 63.6% in anti-TPO levels. (2)(12)(23)(28)

a variety of raw food including nuts, seeds, meats, seafood and more

Common dietary sources of selenium include organ meats, seafood, Brazil nuts, seeds, and certain mushrooms.

Vitamin D

Vitamin D is a prohormone and a non-essential, fat-soluble vitamin (5) that can be synthesized endogenously by the skin with exposure to ultraviolet rays from sunlight. In addition to endogenous production, vitamin D in the form of vitamin D3 and its metabolite 25(OH)D3 may be obtained from certain foods, such as fatty fish (e.g., salmon, mackerel, tuna), beef liver, dairy, and egg yolks. Another form of the vitamin, vitamin D2, can be found in variable amounts in mushrooms. (19)

Vitamin D is well-known for its role in maintaining bone health by promoting calcium absorption and bone mineralization. Vitamin D is involved in other key body functions, such as supporting neuromuscular and immune function, reducing inflammation, and regulating cell growth, proliferation, differentiation, and apoptosis. (19)

It is estimated that vitamin D deficiency affects approximately 1 billion people worldwide. Vitamin D deficiency is a risk factor for total mortality and has been associated with several health conditions, including osteoporosis, muscle weakness, rheumatoid arthritis, diabetes, hypertension, cancer, multiple sclerosis, and Hashimoto’s thyroiditis. (15)(30)(27)

Several studies have demonstrated the effectiveness of vitamin D in decreasing concentrations of thyroid peroxidase and thyroglobulin antibodies. (8)(9)(13) Vitamin D supplementation has also been linked to a decrease in thyroid autoimmunity in Hashimoto’s thyroiditis patients treated with levothyroxine. (8) Furthermore, a combination of simvastatin and supplemental vitamin D was more effective in reducing concentrations of thyroid peroxidase and thyroglobulin antibodies than vitamin D supplementation alone. (9)

Cordyceps sinensis

Like many medicinal mushrooms, Cordyceps sinensis has a long history of use in traditional medicines, particularly Chinese and Tibetan medicines. (22) An entomopathogenic fungus, C. sinensis grows on the larva of insects in North America, Asia, Europe, and parts of India. (26) Unfortunately, its yield has decreased more than 90% in the last 25 years, making it increasingly rare and expensive. (10)

Numerous therapeutic benefits have been attributed to the biological activity of C. sinensis and its primary constituent, Cordycepin. It is thought to possess antioxidant, anti-inflammatory, antimicrobial, antitumor, immunomodulatory, hypoglycemic, anti-fatigue, hepatoprotective, and renal protective effects. C. sinensis may also enhance sexual and reproductive function. (10)(26) Preliminary research demonstrates that C. sinensis may balance the ratio of helper T cells and cytotoxic T cells and may contribute to a decrease in anti-TPO antibodies in patients with Hashimoto’s thyroiditis. (6)

Cordyceps sinensis extract

C. sinensis grows on the larva of insects in North America, Asia, Europe, and parts of India.


Cannabis sativa L., commonly referred to as marijuana, (16) is a herbaceous plant that has been used recreationally and medicinally for over 5,000 years. While the use of cannabis has traditionally been controversial, acceptance of the plant as a therapeutic approach for certain health conditions continues to grow. (1)

The medicinal effects of cannabis have thus far been attributed to phytocannabinoids, or plant cannabinoids, which interact with cannabinoid receptors, CB1 and CB2, within the endocannabinoid system (ECS). (21) Found within the body’s central and peripheral nervous systems, the ECS is a lipid signaling system that plays an important role in regulating many body functions and maintaining homeostasis. (3)

A recent study found that marijuana use may be associated with beneficial effects on thyroid function and autoimmunity. It has been shown that recent marijuana users (used within the past 30 days) have lower TSH and anti-thyroperoxidase antibody levels (11)

The bottom line

While the cause of Hashimoto’s thyroiditis remains to be determined, research has demonstrated the beneficial effects of certain nutrients and plants, including selenium, vitamin D, Cordyceps sinensis, and cannabis. A protocol using natural supplements can be used therapeutically on its own or as an adjunct to existing treatment for thyroid conditions. If you’re a patient, we recommend speaking with your healthcare provider to find out if these supplements are right for your wellness plan.

Article by FullScript 
Written by 
Medically reviewed by 
Dr. Alex Keller, ND

Tags: functional medicine for hypothyroid, integrative medicine for hypothyroid, what causes hypothyroid, hypothyroid remedies, understanding hypothyroid, hashimoto's thyroid disease, supplements for hypothyroid, holistic medicine, natural medicine thyroid

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