Thyroid Vitamins (A, B Complexes, C, D, E, K)

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The thyroid is vital for your health and wellbeing.

The gland releases hormones that control metabolism and regulates vital body functions such as cholesterol levels, body temperature, breathing and heart rate, menstrual cycle, muscle strength, central and peripheral nervous systems, and body weight.

Some people experience have an underactive thyroid or hypothyroidism – meaning their gland doesn’t produce sufficient amounts of these hormones.

In other individuals, the gland produces an excessive amount of hormones i.e. they have hyperthyroidism.

To manage thyroid health and reduce the symptoms you experience, implementing lifestyle modifications is crucial.

The first thing to reevaluate is diet. Avoid consumption of foods that are detrimental to thyroid health and increase intake of foods and nutrients that support proper functioning of the gland.

This article provides an important rundown of vitamins that benefit your thyroid.

Vitamin A

Vitamin A plays an important role in a human body.

Some of its major benefits include better eye health, stronger immune system, anti-inflammatory effects, skin health, cancer prevention, among others.

Signs of vitamin A deficiency include:

  • Digestive problems
  • Dry, rough to the touch, and splitting hair
  • Easy bruising
  • Nosebleeds
  • Painful and swollen joints
  • Red spots on the skin
  • Rough, scaly, and dry skin
  • Slow metabolism and possible weight gain
  • Slow wound healing
  • Swollen and bleeding gums
  • Weak immune system

Besides these important health benefits, vitamin A also has a positive impact on thyroid health.

One study found that serum TSH concentrations in vitamin A-treated participants were significantly reduced.

Scientists concluded that supplementation with this micronutrient can reduce the risk of subclinical hypothyroidism[i].

Furthermore, evidence shows that vitamin A therapy in patients who are deficient in this micronutrient produces an increase in T3 and T4 levels.

In fact, there is a causal relationship between the pathogenesis of impaired vitamin A metabolism and low T3 levels by either interfering with T4 entry into tissues or through a direct impact on the conversion of T4 to T3[ii].

Thyroid hormones take part in the conversion of beta-carotene into vitamin A.

Beta-carotene belongs to the group of carotenoids and it is the most active precursor of this vitamin.

Since thyroid hormones participate in this conversion, it is not uncommon for patients with hypothyroidism to have lower levels of vitamin A in their body.

Benefits of vitamin A for thyroid health can also extend to the reduction of oxidative stress.

Hypothyroidism is strongly related to oxidative stress[iii] and vitamin A acts as antioxidant meaning it can address this problem.

Moreover, studies show that lower levels of this vitamin can cause oxidative stress and mitochondrial dysfunction[iv] in the body.

Vitamins B

B complex includes eight vitamins:

  • B1 (thiamine)
  • B2 (riboflavin)
  • B3 (niacin)
  • B5 (pantothenic acid)
  • B6 (pyridoxine)
  • B7 (biotin)
  • B9 (folic acid)
  • B12 (cobalamin)

Vitamins B are powerful and deliver a wide array of benefits including the production of new cells, antioxidant properties, red blood cell production, regulation of nervous and digestive systems, hormone regulation, and many others.

Symptoms of deficiency to vitamins from B complex greatly depend on the type of vitamin but in most cases affected individual experiences the following:

  • Anemia
  • Confusion
  • Dermatitis (skin rash)
  • Fatigue
  • Infections
  • Irritability
  • Nausea
  • Tingling in the feet and hands
  • Weakness

Considering the complex revolves around different vitamins and each of them has the tremendous potential to improve our health, it is logical to assume some of these micronutrients can make a positive impact on thyroid.

Probably the biggest effect on the thyroid is made by vitamin B12.

Evidence demonstrates that vitamin B12 deficiency is highly prevalent among hypothyroid patients[v] and higher levels of cobalamin can help alleviate symptoms you experience.

When a patient is deficient in vitamin B12, he/she is less likely to respond to treatment for hypothyroidism and manage the symptoms they experience.

Vitamin B2 or riboflavin also has an impact on thyroid function. Riboflavin is required for the regulation of thyroid enzyme and production of corticosteroids.

Without this vitamin, the production of T4 would be suppressed and adrenal glands wouldn’t be able to secrete their hormones.

Deficiency in vitamin B2 can diminish thyroid function. At the same time, diminished thyroid functioning or hypothyroidism can diminish levels of this vitamin too.

In one study, levels of Vitamin B2 in participants are decreased to levels observed in riboflavin deficiency[vi].

Thiamine or vitamin B1 is linked to thyroid fatigue that is common among patients with hypothyroidism.

When battling thyroid problems, a patient may not receive the adequate levels of thiamine due to malabsorption issues in the gut.

Treatment with the vitamin led to complete or partial regression of the fatigue[vii].

Folic acid

As seen above, folic acid belongs to the group of vitamins from B complex. The body needs this vitamin to produce and maintain new cells and prevent changes to the DNA would lead to cancer.

Folic acid deficiency induces these symptoms:

  • Anemia
  • Constipation, bloating, IBS
  • Developmental problems during pregnancy and infancy
  • Irritability, mood changes
  • Low energy levels
  • Pale skin
  • Premature hair graying
  • Tender, swollen tongue and canker sores
  • Weaker immunity

In healthy people, folic acid is converted in the body to l-methyl folate i.e. the biologically active form of Vitamin B9.

In cases of hypothyroidism, there is a reduction of the methylenetetrahydrofolate reductase enzyme which participates in the production of l-methyl folate in your liver.

Decreased levels of the active form of the vitamin lead to the excessive amount of homocysteine.

Higher levels of homocysteine open the door to a higher prevalence of cardiovascular diseases in hypothyroidism.

A growing body of evidence shows that although levothyroxine decreases serum homocysteine, it is the combination with folic acid[viii] that empowers this important effect.

We can say that intake of folic acid prevents cardiovascular events in patients with underactive thyroid through reduction of homocysteine levels.

There are some indications that patients with hyperthyroidism are deficient in this vitamin.

Lower levels of folic acid, in this case, occur due to increased metabolic demand for this nutrient and generalized increase in coenzyme requirements linked with the hyperthyroid state[ix].

Vitamin C

Our body doesn’t produce vitamin C which is why it is necessary to obtain it through the diet.

Deficiency in this vitamin isn’t quite common, but lower levels of vitamin C in the body usually generate these signs:

  • Bruising
  • Dental problems
  • Dry skin and hair
  • Fatigue
  • Infections
  • Joint and muscle aches and pains
  • Mood swings
  • Weight loss

We already have gone into great detail on the effects of vitamin c on thyroid health in this article. But a quick summary can be found below.

Vitamin C works as an antioxidant and works to reduce the levels of oxidative stress.

It is needless to mention that oxidative stress can be harmful to thyroid patients who suffer from both hypo- and hyperthyroidism.

In addition, evidence shows that vitamin C is of huge importance for absorption of thyroid hormone T4.

One study found that serum concentrations of TSH, free T4, and T3 improved while participants were on vitamin C and this vitamin improves absorption of levothyroxine (common therapy for hypothyroidism).

Serum T4 were higher with vitamin C use in 30 out of 31 participants of the study[x] published in the Journal of Clinical Endocrinology and Metabolism.

Furthermore, evidence also shows that vitamin C improves hypothyroidism-induced learning and memory impairment[xi].

This discovery is of crucial importance because memory problems and decrease learning abilities are common symptoms of hypothyroidism.

Besides the improved absorption of levothyroxine and sharper memory, vitamin C can help lower cortisol levels which slow our metabolism thus leading to decreased production of T3 and T4.

In addition, this important vitamin has the tremendous potential to manage cholesterol levels in our body.

As you already know, the underactive thyroid gland is strongly linked to an increase in LDL or bad cholesterol that is a major risk factor for cardiovascular diseases and events.

Vitamin D

There exists a direct correlation between vitamin d and thyroid health.

It is often the case that hypothyroidism occurs when the body lacks sufficient amounts of vitamin d.

We go into more detail about this relationship in our article here. For the busy folk who do not want to read another article, below is a short summary of one of the research studies.

In a research study conducted by the University of California – Los Angeles (UCLA), researchers gave one group of mice sufficient amounts of vitamin d, while not giving the vitamin to a different group of mice.

After some time, they observed and recorded the levels of T4 (thyroxine) in both the mice.

The mice supplemented with vitamin d, had normal levels as can be expected.

However, the group of mice not given vitamin d, had levels of T4 far below normal and developed hypothyroidism.

In addition, the mice without vitamin d, had slower immune systems and were more prone to injuries.

Although the study was done on mice, the research was significant in making a connection in the relationship of thyroid health and vitamin d.

Vitamin E

Vitamin E is one of the most powerful antioxidants in our body.

Adequate levels of this vitamin are necessary for balance in cholesterol levels, disease prevention through fighting free radicals, healthy skin and hair, hormone balance, improved vision, physical endurance and muscle strength, and many other processes.

Symptoms of a deficiency in vitamin E include:

  • Gastrointestinal diseases
  • Leg cramps
  • Muscle weakness
  • Slow tissue healing

Through its antioxidant effects, vitamin C improves symptoms of hypothyroidism.

Remember, a major aspect of the underactive thyroid gland is oxidative stress!

Chinese scientists carried out a study which found that levothyroxine therapy with vitamin E supplementation has the potential to ameliorate cognitive deficit associated with hypothyroidism and decrease oxidative stress status[xii].

Vitamin E has tremendous power to improve thyroid health, more than we even realize.

For example, evidence shows that long-term supplementation with a two-fold dose of iodine can induce iodine-deficient thyroid involution and pose as a catalyst for iodine-induced cytotoxicity.

Unsurprisingly, oxidative stress has a big impact on the pathophysiology of the iodine-induced toxicity.

This is where vitamin E steps in! The micronutrient, which happens to be a potent antioxidant, increases thyroid antioxidant defenses and inhibits cytotoxicity[xiii].

The positive impact of vitamin E also extends to hyperthyroidism.

A group of scientists from Turkey discovered that hyperthyroidism enhances the components of the antioxidant system in the erythrocytes (red blood cells).

Supplementation with this vitamin reduces the burden of oxidative stress in patients who are diagnosed with hyperthyroidism[xiv].

Vitamin K

Vitamin K is a micronutrient that plays a crucial role in blood clotting which prevents excessive bleeding.

Let’s not forget about the role of vitamin K in bone and joint strength which is why it is widely used by patients with osteoporosis.

Symptoms of vitamin K deficiency include:

  • Bleeding in mucus membranes that line areas inside the human body
  • Dark black stool containing blood
  • Easy bruising
  • Heavy menstrual periods
  • Small blood clots underneath the nails

Thyroid has an interesting relationship with vitamin K.

Evidence shows that thyroid hormones influence the vitamin K-dependent plasma factors of blood coagulation[xv].

Basically, thyroid and its hormones affect the vitamin K-dependent blood clotting process.

Thyroid hormone, together with other hormones of the hypothalamic-pituitary-thyroid axis, participates in the regulation of the synthesis and secretion of vitamin K-dependent factors that play a role in blood clotting.

Based on this fact, low production of thyroid hormones also has a negative impact on blood clotting.

This explains why patients with hypothyroidism have a higher risk of bleeding while individuals with hyperthyroidism have a higher risk of thrombosis[xvi].

While vitamin K doesn’t have some specific hypo- or hyperthyroidism benefits, at least not proven by science, your thyroid has a major influence on blood clotting and vitamin K is essential for this process.

Adequate blood clotting requires sufficient levels of vitamin A and proper thyroid functioning.

It is safe to say benefits of vitamin K for patients with hypo or hyperthyroidism will soon be unraveled as scientists are paying more attention to the roles of different nutrients in the management of thyroid disorders.


One of the most beneficial ways to support thyroid health, and overall wellbeing, is to enrich the diet with multiple vitamins and minerals.

This post focused on vitamins that benefit your thyroid in one way or another. Strive to include these vitamins into your diet.

Many thyroid supplements for underactive thyroids contain these vitamins which may help improve your thyroid health. 

There are other natural methods of boosting thyroid hormone which may help as well.


[i] Farhangi MA, Keshavarz SA, Eshraghian M, et al. The effect of vitamin A supplementation on thyroid function in premenopausal women. The Journal of the American College of Nutrition 2012 Aug;31(4):268-74

[ii] Morley JE, Russell RM, Reed A, et al. The interrelationship of thyroid hormones with vitamin A and zinc nutritional status in patients with chronic hepatic and gastrointestinal disorders. The American Journal of Clinical Nutrition August 1981, vol. 34 no. 8, 1489-1495

[iii] Chakrabarti SK, Ghosh S, Banerjee S, Mukherjee S, Chowdhury S. Oxidative stress in hypothyroid patients and the role of antioxidant supplementation. Indian Journal of Endocrinology and Metabolism. 2016;20(5):674-678. doi:10.4103/2230-8210.190555.

[iv] Chiu H-J, Fischman DA, Hammerling U. Vitamin A depletion causes oxidative stress, mitochondrial dysfunction, and PARP-1-dependent energy deprivation. The FASEB Journal. 2008;22(11):3878-3887. doi:10.1096/fj.08-112375.

[v] Jabbar A, Yawar A, Waseem S, et al. Vitamin B12 deficiency common in primary hypothyroidism. The Journal of the Pakistan Medical Association 2008 May;58(5):258-61

[vi] Cimino JA, Jhangiani S, Schwartz E, et al. Riboflavin metabolism in the hypothyroid human adults. Experimental Biology and Medicine February 1987, vol. 184 no. 2, 151-153. Doi: 10.3181/00379727-184-42459

[vii] Costantini A, Pala MI. Thiamine and Hashimoto’s thyroiditis: a report of three cases. The Journal of Alternative and Complementary Medicine 2014 Mar;20(3):208-11. Doi: 10.1089/acm.2012.0612

[viii] Ziaee A, Hajibagher Tehrani N, Hosseinkhani Z, Kazemifar A, Javadi A, Karimzadeh T. Effects of folic acid plus levothyroxine on serum homocysteine level in hypothyroidism . Caspian Journal of Internal Medicine. 2012;3(2):417-420.

[ix] Lindebaum J, Klipstein A. Folic acid clearances and basal serum folate levels in patients with thyroid disease. Journal of Clinical Pathology 1964 17, 666-670. Doi: 10.1136/jcp.17.6.666

[x] Jubiz W, Ramirez M. Effect of vitamin C on the absorption of levothyroxoine in patients with hypothyroidism and gastritis. Journal of Clinical Endocrinology and Metabolism 201 4 Jun;99(6):E1031-4. Doi: 10.1210/jc.2013-4360

[xi] Beheshti F, Karimi S, Vafaee F, et al. The effects of vitamin C on hypothyroidism-associated learning and memory impairment in juvenile rats. Metabolic Brain Disease 2017 Jun;32(3):703-715. Doi: 10.1007/s11011-9954-y

[xii] Pan T, Zhong M, Zhong X, et al. Levothyroxine replacement therapy with vitamin E supplementation prevents oxidative stress and cognitive deficit in experimental hypothyroidism. Endocrine 2013 Apr;43(2):434-9. Doi: 10.1007/s12020-012-9801-1

[xiii] Jiashu Y, Zhongyan S, Chong W, et al. Vitamin E ameliorates iodine-induced cytotoxicity in thyroid. Journal of Endocrinology 2011, 209, 299-306

[xiv] Seven A, Seymen O, Hatemi S, et al. Antioxidant status in experimental hyperthyroidism: effect of vitamin E supplementation. Clinical Chimica Acta 1996 Dec 9;256(1):65-74

[xv] Negrev NN, Radev RZ, Velikova MS, et al. Effects of the hormones of the thyroid axis on the vitamin K-dependent plasma factors of blood coagulation (II, VII, IX, and X). International Journal of Immunopathology and Pharmacology 2008 Jan-Mar;21(1):221-6. Doi: 10.1177/039463200802100125

[xvi] Squizzato A, Romualdi E, Buller HR, Gerdes VEA. Thyroid dysfunction and effects on coagulation and fibrinolysis: a systematic review. The Journal of Clinical Endocrinology and Metabolism July 2007, vol. 92 no. 7, 2415-2420. Doi: 10.1210/jc.2007-0199

1 Comment
  1. Reply
    Pamela Collins May 18, 2021 at 7:04 pm

    although this is all good information. My real question is what is the best multi vitamin that will include all of these needed supplements for hypo thyroids I have a foiba about taking a multitude of pills.
    What has all of this research come up with? If anything.

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