ingestible · for thyroid support
Vitamin D
Reviewed by the Nimbera editorial team · Last updated May 2026
How to use
For those with low blood levels, typical repletion is 1000-4000 IU of vitamin D3 per day with a meal containing fat, or a doctor-directed higher dose for confirmed deficiency. Aim for a blood 25-hydroxyvitamin D in the 30-50 ng/mL range and retest after 8-12 weeks.
How it works
Vitamin D receptors are present on immune and thyroid cells, and the active hormone helps regulate T-cell activity and dampen autoimmune inflammation. Correcting a deficiency is thought to reduce the immune attack on the thyroid, which is why benefit is strongest in people who start out deficient.
Where to buy
Any pharmacy, grocery store, or online. Example brands: NOW Foods Vitamin D3, Nordic Naturals Vitamin D3, Thorne Vitamin D/K2.
Typical cost: $5-$15 per month
Safety notes
Excess vitamin D can cause high blood calcium (nausea, kidney stones, confusion). Do not exceed 4000 IU/day long-term without testing and medical guidance. People with sarcoidosis, hyperparathyroidism, or kidney disease should only supplement under supervision. Ideally dose based on a blood test rather than guessing.
Drug & supplement interactions
- Always tell your doctor or pharmacist about any supplements you take.
- Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
- Herbal remedies can affect how the body absorbs or metabolises drugs.
- Check drugs.com interactions checker before starting.
Clinical source
PubMed Central - Zhang et al. 2023This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.