Hypothyroidism
Supplements studied for hypothyroidism.
Overview
Six supplements are indexed for hypothyroidism (17 studies), all at WA 40 with low ratings. Selenium (9 studies) has the most trials but mixed results on T4-to-T3 conversion and hormone balance. Vitamin D (3 studies) may lower TSH in subclinical hypothyroidism in early work. Inositol plus selenium (2 studies) may improve some thyroid tests and symptoms versus selenium alone.
Ashwagandha (1 study) and Ginger (1 study) have preliminary single-trial data suggesting possible symptom or hormone changes, mainly in mild or medicated hypothyroidism. Evidence remains uncertain across all entries. See the heatmap and evidence reviews below.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Selenium | ★★★★★ | Low |
| Vitamin D | ★★★★★ | Low |
| Inositol | ★★★★★ | Low |
| L-Carnitine | ★★★★★ | Low |
| Ginger | ★★★★★ | Low |
| Ashwagandha | ★★★★★ | Low |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
6 supplements for rated at least stars. All purchase bands. No minimum star filter.
SeleniumView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Selenium is important for making the active thyroid hormone T3 from its inactive form T4.
- If someone has low selenium, this conversion can be less effective, leading to imbalanced thyroid hormone levels.
- Taking selenium supplements sometimes helps improve this conversion, but studies give mixed results.
- Selenium can cause problems if iodine levels are low, as it speeds up hormone changes without enough iodine to keep up.
- For most people with enough iodine, selenium does not have a big effect on thyroid hormones.
- In pregnant women with thyroid problems, selenium might help protect the thyroid after birth.
- Selenium taken with other nutrients like inositol may help thyroid function, but it’s unclear if selenium alone is responsible.
Browse 9 studies
Clinical trialSupplementation with myo-inositol and Selenium improves the clinical conditions and biochemical features of women with or at risk for subclinical hypothyroidism2022n=48
In 148 women with subclinical hypothyroidism over 6 months, myo-inositol plus selenium (600 mg plus 83 mcg/day) improved TSH, autoantibodies, and symptoms.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 83 mcg/day
- Population
- Women
- Participants
- 48
- Ages
- 18–50
MetaInterventions for clinical and subclinical hypothyroidism in pregnancy2010n=314
A Cochrane review of 3 pregnancy hypothyroidism RCTs found insufficient evidence that selenium or other interventions clearly improve obstetric outcomes beyond levothyroxine.
- Effect
- No Benefit
- Population
- Women
- Participants
- 314
RCTRandomized controlled trial of the effect of selenium supplementation on thyroid function in the elderly in the United Kingdom2008
In 501 elderly UK volunteers over 6 months, selenium 100–300 mcg/day did not significantly change thyroid hormone levels despite modest increases in plasma selenium.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 100–300 mcg/day
- Population
- Adults
- Ages
- 60–64
RCTThe influence of selenium supplementation on postpartum thyroid status in pregnant women with thyroid peroxidase autoantibodies2007
In 77 TPOAb-positive pregnant women, selenomethionine 200 mcg/day during and after pregnancy reduced postpartum thyroid dysfunction (28.6% vs 48.6%) versus placebo.
- Effect
- Benefit
- Dose
- 200 mcg/day
- Population
- Women
ObservationalSelenium status in an iodine deficient population of the West Ivory Coast2001
In iodine-deficient Ivory Coast populations, Glanlé residents had lower selenium, glutathione peroxidase, and vitamin E status than Abidjan controls, suggesting combined deficiency and oxidative stress.
Case reportSelenium-induced thyroid dysfunction1997
A case report described IV high-dose selenite for sepsis causing marked hypothyroidism that normalized after iodine supplementation in a severely iodine-deficient patient.
- Population
- Patients With Inflammatory Diseases
RCTLow selenium status in the elderly influences thyroid hormones1995n=24
In 109 healthy adults and a nursing-home trial, lower selenium status in elderly subjects correlated with lower T3/T4 ratios, supporting selenium's role in peripheral thyroid hormone conversion.
- Population
- Older adults
- Participants
- 24
Selenium deficiency mitigates hypothyroxinemia in iodine-deficient subjects1993
In iodine- and selenium-deficient Zaire subjects, selenium supplementation could worsen hypothyroxinemia by increasing T4 deiodination unless iodine or thyroid hormone is also provided.
- Effect
- No Benefit
Effect of selenium supplementation in hypothyroid subjects of an iodine and selenium deficient area: the possible danger of indiscriminate supplementation of iodine-deficient subjects with selenium1991
In northern Zaire, 2 months of selenium supplementation corrected GPX activity but worsened thyroid function in clinically hypothyroid iodine-deficient subjects.
- Effect
- No Benefit
InositolView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Taking a combination of myo-inositol and selenium daily for several months may help improve thyroid hormone levels and reduce symptoms like fatigue and irregular periods in people with hypothyroidism or subclinical hypothyroidism.
- This combination appears to work better than selenium alone in improving some thyroid blood tests and reducing thyroid antibodies.
- However, more research is needed to confirm these benefits and understand how much each ingredient contributes.
Browse 2 studies·1 meta-analysis
MetaInvestigating the effect of combined use of selenium and Myo-inositol supplements on thyroid function and autoimmune characteristics in thyroid disorders: a systematic review and meta-analysis2024
A meta-analysis found combined selenium and myo-inositol improved thyroid function and reduced autoantibodies in thyroid disease versus control.
- Effect
- Benefit
- Population
- Thyroid disorder patients
Clinical trialSupplementation with myo-inositol and Selenium improves the clinical conditions and biochemical features of women with or at risk for subclinical hypothyroidism2022n=48
In 148 women with subclinical hypothyroidism over 6 months, myo-inositol plus selenium (600 mg plus 83 mcg/day) improved TSH, autoantibodies, and symptoms.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 83 mcg/day
- Population
- Women
- Participants
- 48
- Ages
- 18–50
Vitamin DView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is not clear if vitamin D helps with subclinical hypothyroidism.
- Early studies show that taking vitamin D once a week (50,000 IU) for several weeks can lower thyroid hormone levels called TSH by about 20% compared to no vitamin D or compared to the levels before treatment.
Browse 3 studies
RCTEffects of vitamin D supplementation on metabolic parameters, serum irisin and obesity values in women with subclinical hypothyroidism: a double-blind randomized controlled trial2023n=22
In a 12-week RCT of 44 women with subclinical hypothyroidism, 50,000 IU/week vitamin D lowered TSH and total cholesterol and increased irisin versus placebo.
- Effect
- Benefit
- Duration
- 12 weeks
- Dose
- 50000 IU/day
- Population
- Adults
- Participants
- 22
- Ages
- 20–65
RCTOral vitamin D versus acitretin in congenital non-syndromic ichthyosis: double blinded, randomized controlled trial2022n=13
In a 24-week RCT of 24 congenital ichthyosis patients, oral vitamin D 2,000 IU/day reduced disease severity at 12 weeks and lowered RORγt and IL-17 expression, comparable to acitretin at 24 weeks.
- Duration
- 24 weeks
- Dose
- 2000 IU/day
- Population
- Patients
- Participants
- 13
RCTThe Effect of Vitamin D Replacement on Patient with Subclinical Hypothyroidism: A Pilot Randomized Clinical Trial2020n=59
In 40 patients with subclinical hypothyroidism and vitamin D deficiency, 2 months of vitamin D replacement lowered mean TSH from 6.89 to 3.34 mIU/L.
- Effect
- Benefit
- Dose
- 50000 IU
- Population
- Women
- Participants
- 59
AshwagandhaView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain if ashwagandha helps hypothyroidism.
- Early research found that taking a specific ashwagandha extract twice daily for 8 weeks increased thyroid hormone levels and lowered TSH in adults with mild hypothyroidism.
- Effects in more severe cases or those taking thyroid medication are not known.
Browse 1 study
RCTEfficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial2018n=25
In 50 adults with subclinical hypothyroidism over 8 weeks, ashwagandha 600 mg/day normalized TSH, T3, and T4 in a subset and improved thyroid indices versus placebo.
- Effect
- Benefit
- Duration
- 8 weeks
- Dose
- 600 mg/day
- Population
- Adults
- Participants
- 25
- Ages
- 18–50
GingerView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- In people with hypothyroidism taking thyroid medication, a small study found that taking ginger powder twice a day for 1 month helped improve symptoms like feeling cold, constipation, dry skin, weight gain, dizziness, and memory problems.
- Ginger also helped reduce weight and improved blood sugar and cholesterol levels.
- However, it did not improve hair loss, hearing, nail problems, speech, or feelings of depression.
- More studies are needed to confirm these results.
Browse 1 study
RCTEfficacy of Ginger Supplementation in Relieving Persistent Hypothyroid Symptoms in Patients with Controlled Primary Hypothyroidism: A Pilot Randomized, Double‑Blind, Placebo‑Controlled Clinical Trial2022
In 60 euthyroid hypothyroid patients with persistent symptoms, ginger 500 mg twice daily for 30 days significantly reduced fatigue and other symptom scores versus placebo.
- Effect
- Benefit
- Duration
- 30 days
- Dose
- 500 mg 2×/day
- Population
- Hypothyroid patients
- Ages
- 20–60
L-CarnitineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- A small study in people with secondary hypothyroidism showed that taking L-carnitine (990 mg twice daily for 12 weeks) along with standard thyroid medication did not reduce overall fatigue compared to placebo.
- However, younger patients under 50 experienced improvements in both physical and mental tiredness, and people who had thyroid surgery for cancer reported improvement in mental fatigue.
Browse 1 study
RCTL-carnitine supplementation for the management of fatigue in patients with hypothyroidism on levothyroxine treatment: a randomized, double-blind, placebo-controlled trial2016n=30
In 30 hypothyroid patients on levothyroxine with persistent fatigue, L-carnitine 1,980 mg/day for 12 weeks improved fatigue scores versus baseline.
- Effect
- Benefit
- Duration
- 12 weeks
- Dose
- 1980 mg/day
- Population
- Hypothyroid patients
- Participants
- 30
- Avg age
- ~50
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Selenium | ★★★★★52% | 9 | 0 | 53% |
| Vitamin D | ★★★★★48% | 3 | 0 | 18% |
| Inositol | ★★★★★48% | 2 | 1 | 12% |
| Ashwagandha | ★★★★★44% | 1 | 0 | 6% |
| Ginger | ★★★★★44% | 1 | 0 | 6% |
| L-Carnitine | ★★★★★44% | 1 | 0 | 6% |