Hypothyroidism (Underactive Thyroid): natural remedies and the evidence behind them
Hypothyroidism occurs when the thyroid gland doesn't produce enough thyroid hormone, leading to symptoms like fatigue, weight gain, and sluggishness.
8 options · 2 graded B · 2 graded C · 4 traditional or ungraded
How is your underactive thyroid affecting you, and where do you want to focus?
I feel stressed, foggy, and burned out, and want something to steady my energy and mood
Ashwagandha
Supported by smaller clinical studies· Centuries of traditional use (Evidence grade B · Traditional use long-standing)Long-standing traditional stapleSmall RCT improved thyroid levels in mild (subclinical) cases
- Why this matches
- If low energy and a stress-driven, sluggish feeling are wearing you down, ashwagandha is an adaptogen traditionally used to steady energy and stress — dimensions that often ride along with an underactive thyroid.
- Why try it
- Ashwagandha is a traditional Ayurvedic adaptogen. In a small 8-week double-blind, placebo-controlled trial in adults with subclinical (mild) hypothyroidism, a standardized root extract significantly improved thyroid hormone levels (TSH, T3, T4) versus placebo, and it is also valued for steadying stress and energy. The trial was small and limited to mild cases, so treat this as promising support rather than a replacement for prescribed thyroid care.
- Dose or use
- Commonly 300–600 mg of a standardized root extract daily, taken with food; give it several weeks.
- Time to results
- Typically 6–8 weeks
- Key study
- Randomized controlled trial (2018, PMID 28829155): Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients. In this 8-week double-blind, placebo-controlled pilot of 50 adults, 600 mg/day of ashwagandha root extract significantly improved serum TSH, T3, and T4 versus placebo. Encouraging but small and limited to subclinical hypothyroidism.
- Caution
- Avoid in pregnancy, and use caution if you have autoimmune (Hashimoto's) thyroid disease or take thyroid or sedative medication — talk to your doctor first, as it may raise thyroid hormone levels.
Exercise
Limited human trials so far· Most of the research is laboratory or animal work (Evidence grade C · No traditional record)Supports metabolism; direct thyroid data is limited
- Why this matches
- If low energy, weight gain, and a sluggish metabolism are your main struggle, regular movement is one of the most reliable everyday ways to support your metabolism, mood, and weight while you address thyroid function.
- Why try it
- Everyday movement is well established for supporting metabolism, weight, and energy. Its direct effect on thyroid markers is less certain — the strongest thyroid-specific signal so far comes from a single mind-body exercise trial rather than from general cardio and strength work.
- Dose or use
- Aim for around 150 minutes of moderate activity per week, mixing cardio and strength; even gentle, consistent movement counts if fatigue is high.
- Time to results
- Typically 4–12 weeks of consistent effort
- Key study
- RCT (2025, PMID 40582060): a Baduanjin (mind-body) exercise program improved lipid profile, blood pressure, and TSH in elderly people with subclinical hypothyroidism. This is one specific mind-body trial; general cardio and strength work has not been shown to change thyroid markers directly.
- Caution
- Start gradually if fatigue is severe, and check with your doctor before beginning a new program if you have heart or joint concerns.
I'd rather support my thyroid directly with key nutrients and herbs
Ashwagandha
Supported by smaller clinical studies· Centuries of traditional use (Evidence grade B · Traditional use long-standing)Long-standing traditional stapleSmall RCT improved thyroid levels in mild (subclinical) cases
- Why this matches
- If low energy and a stress-driven, sluggish feeling are wearing you down, ashwagandha is an adaptogen traditionally used to steady energy and stress — dimensions that often ride along with an underactive thyroid.
- Why try it
- Ashwagandha is a traditional Ayurvedic adaptogen. In a small 8-week double-blind, placebo-controlled trial in adults with subclinical (mild) hypothyroidism, a standardized root extract significantly improved thyroid hormone levels (TSH, T3, T4) versus placebo, and it is also valued for steadying stress and energy. The trial was small and limited to mild cases, so treat this as promising support rather than a replacement for prescribed thyroid care.
- Dose or use
- Commonly 300–600 mg of a standardized root extract daily, taken with food; give it several weeks.
- Time to results
- Typically 6–8 weeks
- Key study
- Randomized controlled trial (2018, PMID 28829155): Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients. In this 8-week double-blind, placebo-controlled pilot of 50 adults, 600 mg/day of ashwagandha root extract significantly improved serum TSH, T3, and T4 versus placebo. Encouraging but small and limited to subclinical hypothyroidism.
- Caution
- Avoid in pregnancy, and use caution if you have autoimmune (Hashimoto's) thyroid disease or take thyroid or sedative medication — talk to your doctor first, as it may raise thyroid hormone levels.
Selenium
Supported by smaller clinical studies· Centuries of traditional use (Evidence grade B · Traditional use long-standing)Long-standing traditional stapleTrace mineral behind T4-to-T3 conversion
- Why this matches
- If you want to support your thyroid directly, selenium powers the enzymes that convert stored thyroid hormone (T4) into its active form (T3) and helps protect the gland from oxidative stress.
- Why try it
- Selenium powers the enzymes that activate thyroid hormone and help protect the gland from oxidative stress. In pooled randomized trials in autoimmune (Hashimoto's) thyroiditis — the most common cause of an underactive thyroid — selenium modestly lowered TSH and reduced thyroid antibodies, though it did not change thyroid hormone levels. It is a reasonable support, not a substitute for prescribed thyroid treatment.
- Dose or use
- Commonly around 100–200 mcg daily; a couple of Brazil nuts is a food source. Keep total intake under 400 mcg/day.
- Time to results
- Typically 8–12 weeks
- Key study
- Systematic review and meta-analysis of RCTs (2024, PMID 38243784): Selenium Supplementation in Patients with Hashimoto Thyroiditis. Across 35 trials, selenium modestly lowered TSH in people not on thyroid hormone and reduced thyroid peroxidase antibodies (TPOAb); it did not change free T4 or T3, so it supports autoimmune thyroid health rather than replacing thyroid treatment.
- Caution
- Selenium has a narrow safe range — too much can cause hair loss, brittle nails, and nerve problems. Don't stack multiple high-dose supplements.
Iodine
Centuries of traditional use across more than one tradition· Human evidence not yet assessed (Evidence grade not assigned · Traditional use classical)Classical use across multiple traditionsThe raw material your thyroid needs to make hormone
- Why this matches
- If you want to support your thyroid directly, iodine is the building block your gland uses to make thyroid hormone — a genuine gap can leave it unable to keep up.
- Why try it
- Iodine is the direct precursor of thyroid hormones (T4 and T3), and its library entry lists hypothyroidism and goiter among its uses. Correcting a true iodine shortfall is well established; supplementing when you're not deficient is not, so this is best guided by testing.
- Dose or use
- Only supplement to correct a confirmed shortfall; the adult daily requirement is about 150 mcg. Ask your doctor before taking high-dose iodine.
- Time to results
- Varies; weeks to months when a true deficiency is corrected
- Key study
- Iodine is the established substrate for thyroid hormone; correcting a documented deficiency is a recognized approach, but routine supplementation without deficiency is not supported and can backfire.
- Caution
- More is not better: excess iodine can worsen thyroid function, and in autoimmune (Hashimoto's) hypothyroidism it can aggravate the condition. Do not take high doses without medical guidance.
I'm fighting low energy, weight gain, or a sluggish metabolism and want everyday habits that help
Exercise
Limited human trials so far· Most of the research is laboratory or animal work (Evidence grade C · No traditional record)Supports metabolism; direct thyroid data is limited
- Why this matches
- If low energy, weight gain, and a sluggish metabolism are your main struggle, regular movement is one of the most reliable everyday ways to support your metabolism, mood, and weight while you address thyroid function.
- Why try it
- Everyday movement is well established for supporting metabolism, weight, and energy. Its direct effect on thyroid markers is less certain — the strongest thyroid-specific signal so far comes from a single mind-body exercise trial rather than from general cardio and strength work.
- Dose or use
- Aim for around 150 minutes of moderate activity per week, mixing cardio and strength; even gentle, consistent movement counts if fatigue is high.
- Time to results
- Typically 4–12 weeks of consistent effort
- Key study
- RCT (2025, PMID 40582060): a Baduanjin (mind-body) exercise program improved lipid profile, blood pressure, and TSH in elderly people with subclinical hypothyroidism. This is one specific mind-body trial; general cardio and strength work has not been shown to change thyroid markers directly.
- Caution
- Start gradually if fatigue is severe, and check with your doctor before beginning a new program if you have heart or joint concerns.
Vitamin D
Limited human trials so far· Most of the research is laboratory or animal work (Evidence grade C · No traditional record)Preliminary single-trial signal on metabolic markers
- Why this matches
- For those managing weight and metabolic sluggishness, vitamin D supplementation has been studied specifically in women with subclinical hypothyroidism for its effect on metabolic health.
- Why try it
- Early evidence from a single trial suggests vitamin D may influence metabolic and body-composition markers in women with subclinical hypothyroidism. This is preliminary, based on surrogate measures rather than thyroid or clinical outcomes, and has not been confirmed by larger studies.
- Dose or use
- Typically 1,000–2,000 IU daily with a meal; follow your healthcare practitioner's guidance based on your blood levels.
- Time to results
- Typically 8–12 weeks
- Key study
- RCT (2023, PMID 38179303): Effects of vitamin D supplementation on metabolic parameters, serum irisin and obesity values in women with subclinical hypothyroidism: a double-blind randomized controlled trial.
- Caution
- High doses can cause toxicity; get your levels tested before supplementing long-term, especially if you have kidney issues.
I want to check whether a hidden nutrient gap is making things worse (get tested first)
Iodine Deficiency
Centuries of traditional use· Human evidence not yet assessed (Evidence grade not assigned · Traditional use long-standing)Long-standing traditional stapleIodine gap is a classic, direct cause of low thyroid
- Why this matches
- If you're checking whether a nutrient gap is dragging your thyroid down, iodine is the most direct one to consider — it's the raw material your gland needs to make hormone.
- Why try it
- Iodine deficiency is a textbook, correctable cause of hypothyroidism and goiter. Confirming your status is a practical root-cause step rather than a treatment in itself.
- Dose or use
- Ask your provider about your iodine status (a dietary review or a urine iodine test) before supplementing.
- Time to results
- Correcting a true deficiency can take weeks to months
- Key study
- A documented iodine shortfall is a recognized, direct cause of an underactive thyroid; this is a root-cause check, not a treatment claim — ask your provider to assess your status.
- Caution
- Don't self-correct with high-dose iodine — excess can worsen thyroid function, especially in autoimmune (Hashimoto's) thyroid disease.
Selenium Deficiency
Centuries of traditional use· Human evidence not yet assessed (Evidence grade not assigned · Traditional use long-standing)Long-standing traditional stapleLow selenium can impair T4-to-T3 conversion
- Why this matches
- If you're looking for a hidden nutrient gap behind your symptoms, low selenium can impair how your body activates thyroid hormone and defends the gland from oxidative stress.
- Why try it
- Selenium's library entry notes its critical role in thyroid hormone metabolism; if you're low, correcting it may support how efficiently your body uses thyroid hormone.
- Dose or use
- Ask your provider whether checking or gently correcting selenium makes sense before adding supplements.
- Time to results
- Correction typically takes 8–16 weeks
- Key study
- Selenium is essential for the enzymes that activate thyroid hormone; this is a root-cause check, not a treatment claim — ask your provider before supplementing.
- Caution
- Selenium has a narrow safe range; don't take high-dose supplements to 'top up' without knowing your status.
Vitamin D Deficiency
Centuries of traditional use· Human evidence not yet assessed (Evidence grade not assigned · Traditional use long-standing)Long-standing traditional stapleLow vitamin D may compound thyroid-related symptoms
- Why this matches
- If you're wondering whether a hidden nutritional shortfall is making your hypothyroidism harder to manage, checking your vitamin D status is a practical first step.
- Why try it
- If you're low in vitamin D, correcting that deficiency may help support overall metabolic and immune function, which can be relevant when the thyroid is underperforming.
- Dose or use
- Ask your doctor for a 25-OH vitamin D blood test to know your baseline before supplementing.
- Time to results
- Deficiency correction typically takes 8–16 weeks
- Key study
- Correcting a documented shortfall can support recovery; this is a root-cause check, not a treatment claim — ask your provider to test your levels.
- Caution
- Do not self-prescribe high-dose vitamin D without testing; excess vitamin D accumulates and can cause harm.
Evidence grades describe the strength of published research for Hypothyroidism (Underactive Thyroid), not a promise of results. Nothing here is medical advice — talk to your clinician before starting anything, especially alongside prescription medication.



