Iodine
Last updated: August 9, 2026
Benefits
Needed to make thyroid hormones, which regulate metabolism, growth, and development.
How much you need
Recommended daily amounts by life stage, per NIH and NASEM Dietary Reference Intakes. Where the evidence hasn't been enough to set a full RDA (Recommended Dietary Allowance), NASEM sets an AI (Adequate Intake) instead — both are shown together below.
| Life stage | RDA / AI |
|---|---|
| Children 1–3 | 90 mcg |
| Children 4–8 | 90 mcg |
| Boys 9–13 | 120 mcg |
| Girls 9–13 | 120 mcg |
| Males 14–18 | 150 mcg |
| Females 14–18 | 150 mcg |
| Men 19–50 | 150 mcg |
| Women 19–50 | 150 mcg |
| Men 51–70 | 150 mcg |
| Women 51–70 | 150 mcg |
| Men 71+ | 150 mcg |
| Women 71+ | 150 mcg |
| Pregnancy 14–18 | 220 mcg |
| Pregnancy 19–50 | 220 mcg |
| Lactation 14–18 | 290 mcg |
| Lactation 19–50 | 290 mcg |
Upper limit
This limit applies to total Iodine intake — food and supplements combined.
| Life stage | Tolerable upper limit |
|---|---|
| Children 1–3 | 200 mcg |
| Children 4–8 | 300 mcg |
| Boys 9–13 | 600 mcg |
| Girls 9–13 | 600 mcg |
| Males 14–18 | 900 mcg |
| Females 14–18 | 900 mcg |
| Men 19–50 | 1100 mcg |
| Women 19–50 | 1100 mcg |
| Men 51–70 | 1100 mcg |
| Women 51–70 | 1100 mcg |
| Men 71+ | 1100 mcg |
| Women 71+ | 1100 mcg |
| Pregnancy 14–18 | 900 mcg |
| Pregnancy 19–50 | 1100 mcg |
| Lactation 14–18 | 900 mcg |
| Lactation 19–50 | 1100 mcg |
Sustained excess iodine can disturb thyroid function, causing it to become either over- or under-active.
Best food sources
| Serving | ||
|---|---|---|
| Iodized salt | — | — |
| Seaweed (nori, kelp) | — | — |
| Cod and other white fish | — | — |
| Dairy | — | — |
| Eggs | — | — |
Absorption & caution
Caution: Iodine has a narrow comfortable range — both too little and too much can disrupt the thyroid. If you have a thyroid condition, check with your clinician before using iodine or kelp supplements.
Pairings
Works well with
- Selenium — Selenium-dependent enzymes help the thyroid use iodine to make hormones.
Body systems & goals
Body systems it supports
- Thyroid — Your thyroid sets the pace for your whole metabolism, and it needs these nutrients to make its hormones. Supporting them helps your body maintain steady energy and temperature. (established evidence)
Goals it supports
- Plant-based diet (established evidence)
Frequently asked questions
How much Iodine do adult women need per day?
Adult women (19–50) need 150 mcg of Iodine per day, per NIH/NASEM Dietary Reference Intakes.
How much Iodine do adult men need per day?
Adult men (19–50) need 150 mcg of Iodine per day, per NIH/NASEM Dietary Reference Intakes.
Does pregnancy change how much Iodine you need?
Yes — during pregnancy (ages 19–50) the recommended amount rises to 220 mcg per day, compared with 150 mcg for non-pregnant adult women.
Is there an upper limit for Iodine?
Yes — for adults 19–50, the tolerable upper limit is 1100 mcg. Sustained excess iodine can disturb thyroid function, causing it to become either over- or under-active.
What foods are highest in Iodine?
Good sources include Iodized salt, Seaweed (nori, kelp), Cod and other white fish, Dairy, and Eggs.
How Tavita handles this
Tavita logs Iodine from both the food you eat and the supplements you take, adding both into one running daily total. It warns you before you reach the tolerable upper limit, counting your combined intake from food and supplements.
Sources
Figures on this page come from the NIH Office of Dietary Supplements fact sheets and the National Academies of Sciences, Engineering, and Medicine (NASEM) Dietary Reference Intake tables — the same dataset that powers the Tavita app. They were independently re-verified by blind re-derivation on August 9, 2026. See the methodology page for how this library is built and kept current.
Tavita is not a medical provider. This page is educational information, not medical advice — talk to your clinician before changing your supplement or medication routine.