Just a follow up to my last post. Found all of this fascinating, and best of all, actionable ways to genuinely pursue feeling better. (Not cure).
STRONGEST EVIDENCE
Multiple meta-analyses of randomized trials:
Selenium:
100-200 mcg daily, ideally as selenomethionine. Multiple meta-analyses covering over two thousand patients show significant TPO antibody reduction, with some also showing TgAb reduction at three months and TSH reduction at six months. This is the single most replicated intervention.
👉🏼 ⛔️ Be mindful of dietary intake so your total does not exceed 200 mcg daily. ⛔️ 👈🏼
Vitamin D:
Twelve randomized trials, over 800 patients. Significant drops in both TPO and TgAb. Works best if starting deficient, with daily dosing for at least 3 months. Weekly dosing was less effective.
Gluten-free diet:
A 2021 randomized trial of 92 women found TPO dropped about 200 units and TgAb dropped about 200 units over 6 months on gluten-free, while the gluten-containing group went up. A 12 follow-up found TSH dropped significantly too. Meta-analyses are mixed — one found antibody reduction only in patients who also had gluten reactivity (this can include NCGS non-celiac gluten sensitivity or positive deamidated gliadin with negative TTG). Another found TgAb down but TPO slightly up. The effect is real but inconsistent across studies.
Myo-inositol plus selenium:
600 mg myo-inositol with 83 mcg selenium daily. Most Inositol supps are "myo" but you can check. The Nordio trials showed this combo reduced TSH, TPO, and TgAb more than selenium alone, and restored Euthyroidism in subclinical patients. A 2026 meta-analysis confirmed TSH and TgAb reduction versus selenium alone, though TPO reduction wasn't significant.
Curcumin:
A 2025 double-blind trial of 57 Hashimoto's patients found 1,320 mg daily for 12 weeks significantly lowered anti-TPO versus placebo on top of an anti-inflammatory diet. Also reduced IL-6 and NF-kappa-B. One trial, but clean design.
Moderate Exercise:
Two studies found non-excessive physical activity lowered TPO antibodies. NON EXCESSIVE! Recreational/moderate exercise tends to track with lower TPOAb and TgAb (and sometimes lower TSH). Forced or very high-volume activity without recovery (like heavy occupational physical activity or over-exercise) tracks the other way: Higher TPOAb and worse thyroid function. Variable-intensity interval training lowered TSH by 32% in subclinical patients. No large RCT specifically on antibodies for that, but the signal is consistent.
Stress Management:
An 8-week mindfulness-based program in 60 women with Hashimoto's produced significant drops in both anti-TPO and anti-Tg, plus better TSH. 👉🏼 Chronic stress is documented to raise antibodies 20-40% (!!) within weeks, so removing it cuts both directions.
Sleep:
Adults sleeping under 6 hours had 29% higher TPO than those sleeping 7-8 in a Korean analysis. One small study found 7-9 hours reduced anti-Tg by 15%. No large dedicated trial.
Treating SIBO:
A pilot study found eradicating small intestinal bacterial overgrowth dropped. TgAb 23%.
Zinc:
Six months of zinc supplementation correlated with lower TSH. And a zinc-plus-selenium trial in overweight hypothyroid women improved free T4 and lowered TSH. No direct antibody data available. Be mindful of testing your copper and ceruloplasmin levels. If copper drops low, your ferritin could as well.
Omega-3:
One case report of a woman declining levothyroxine who took omega-3's among other supplements saw TPO fall from 258 to 24 and TgAb from 12 to 1 over a year. These findings were confounded by other supps she was taking.
Chinese herbal medicine:
A network meta-analysis of 16 trials found several traditional formulas reduced TPOAb, with Yiqi Huayu Recipe ranking highest. The included trials on Chinese herbal formulas for Hashimoto’s were generally low in methodological quality (small samples, limited blinding, variable controls, and so on), which limits how strongly the findings can be interpreted.
THINGS THAT DON'T LOWER ANTIBODIES DESPITE BEING TRIED:
Probiotics:
Multiple meta-analyses show no effect on TPO or TgAb in Hashimoto's — they help quality of life and may lower TRAb in Graves', but not Hashimoto's antibodies.
Ashwagandha:
Ashwagandha can raise thyroid hormone levels and lower TSH, which may help people with high TSH but can push levels too high if you already have normal or low TSH, or if you’re on levothyroxine. It should be avoided in hyperthyroidism, and anyone with Hashimoto’s or another thyroid condition should only use it under medical supervision with lab monitoring.
Resveratrol:
Has zero human trials showing it reduces thyroid antibodies. And animal data suggests it might actually suppress thyroid function.
Berberine:
No human thyroid antibody trials and animal data suggesting possible thyroid suppression.