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Ingredient file // Vitamin or mineral

Calcium Iodate

A useful iodine dose, not a calcium boost

Calcium iodate is a mineral salt added in tiny amounts to supply iodine. Dogs need iodine to make thyroid hormones, but the total dose matters: too little or too much can disrupt thyroid function. Its calcium contribution is negligible.

Role in the food Supporting nutrient
What it is
A manufactured mineral salt added to dog food as a measured source of iodine.
Made from
Iodine compounds and a calcium compound
Main job
Iodine for thyroid hormones
Typical amount
Milligrams per kilogram, depending on other iodine sources
Watch for
Extra iodine supplements alongside complete food
Not the same as
Calcium iodide

Straight answer

Is Calcium Iodate safe for dogs?

Read it as iodine, then check the food

Calcium iodate near other mineral ingredients supplies a small amount of iodine; its list position cannot reveal the dose. Check that the food is labeled complete and balanced for your dog's life stage. If iodine intake needs monitoring, request the finished food's measured total iodine from the maker.

Why it is in the food
Iodine for thyroid hormones

Our read // In our catalog

In 1 of every 2 foods we track

Share of foods that list it

51%

1,628 of the 3,204 foods with an ingredient list on file, from 71 brands. 1,356 dry dog food, 181 wet dog food, 47 frozen dog food.

Each square is 1% of the catalog

Where it sits on the label

Median position 25. In the top five of 0 foods, so it is usually a minor ingredient.

Top five List position, heaviest first

Above the salt

5%

Usually listed after the salt, which caps it at roughly 1% of the recipe in 95% of foods.

Price per lb

Foods with it $3.32
All foods $3.25

Median of the cheapest bag price across 1,111 priced foods, about level with the catalog. The price is the food's, not the ingredient's.

Who leans on it

10%

of the foods that list it are from Royal Canin. 71 brands use it in total.

What it is

How it is made

One documented chemical industry route recovers iodide from liquid left after making organic fluorine compounds. Oxidation and calcium addition yield crystals that can enter feed production. This is one route, not a description of every supplier's process.3,5

  1. 01 // Source Iodide-rich liquid A patented route starts with an iodide-containing waste solution from chemical production.
  2. 02 // Process Oxidized to iodate Chlorine converts dissolved iodide to iodate in the liquid.
  3. 03 // Process Calcium added Calcium chloride reacts with the iodate, causing calcium iodate crystals to separate from the liquid.
  4. 04 // Process Filtered and dried The crystals are filtered, washed with cold water and dried.
  5. 05 // Output Calcium iodate crystals The dried ingredient enters feed supply; anhydrous and hydrated products have different iodine percentages.

What is in it

Composition, dry matter

64.4

% iodine

Average iodine in tested anhydrous powder. The salt supplies iodine; the calcium that comes with such a small addition contributes little to finished food.

Iodine 64.1-64.8%3
Calcium 101-111 g/kg3
Calcium iodate 98.5-99.5%3

These figures describe anhydrous powder, treated here as dry material; the report gives no separate moisture correction. The calcium iodate row measures purity, not another nutrient. Hydrated or coated products have different percentages.3

Why it is in the bag

A tiny addition that supplies the food's iodine

  1. Main nutrition
  2. Supporting nutrient
  3. Does a job
  4. Mostly filler

Makers add calcium iodate to supply iodine, which dogs need to make thyroid hormones. It sits near the end of the list with the other minerals because labels rank ingredients by weight and the dose is tiny. That low position does not make it filler. Tested powder is about 64% iodine, so a very small weight can cover the iodine a food needs. It adds no meaningful calcium.1,3,7

  1. 01

    Supplies measured iodine

    The thyroid uses iodine to make hormones. Assayed calcium iodate lets a formulator add a measured amount while accounting for iodine already present in other ingredients.1,3

  2. 02

    Retains iodine in storage

    A feed mineral trade group reports that iodates hold their iodine better than iodides exposed to moisture or other minerals. That is a formulation reason, although the sheet gives no dog food trial.6

  3. 03

    Uses a premix

    The EFSA feed additive authorization calls for calcium iodate to enter compound feed through a premix. Diluting a trace addition first makes it practical to distribute through a larger batch.3

  4. 04

    Uses recovered iodine

    A patent describes making feed additive crystals from iodide-bearing industrial waste liquid, giving that stream another use. It does not report what dog food makers pay for the ingredient.5

How much AAFCO's published dog food profile sets a minimum of 1 mg total iodine per kg of dry food; other iodine sources change the calcium iodate addition.4

Our read // The claims

What the evidence supports

Strong: controlled studies in dogs agree. Some: small or mixed dog data. Thin: mechanism or lab work only. None: nothing, or the evidence points the other way.

  1. Brands say

    Supplies iodine dogs need for thyroid hormones

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    One iodine-deficient dog had normal thyroid hormone tests within 2 months of changing to iodine-supplemented food. EFSA accepts calcium iodate as an iodine source, but that case did not test this salt separately.1,3

  2. Vets say

    Too much iodine can disrupt thyroid function

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    In a controlled study of 18 puppies, the higher-iodine groups had lower thyroid hormone and higher thyroid stimulating hormone than controls. The study used potassium iodide, so the caution concerns total iodine rather than calcium iodate alone.2

  3. Brands say

    Keeps iodine stable throughout storage

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    A feed mineral trade group says iodates retain iodine during storage. EFSA's 2025 renewal review received no new feed stability data. Neither source shows that this choice improves the health of dogs eating finished food.3,6

  4. Brands say

    Its calcium helps build strong bones

    Outruns the evidence

    Evidence

    1. Strong
    2. Some
    3. Thin
    4. None

    Tested powder contained 101 to 111 g calcium per kg, but recipes use the powder in trace amounts to supply iodine. That contributes negligible calcium to the food. The name does not make it a calcium supplement.3,4

Straight answers

What owners ask

  1. Q01

    Is it just filler?

    No

    It has a specific job: supplying iodine for thyroid hormone production. The amount needed is too small to bulk up a recipe or meaningfully change its protein, fat or calories.3,4

  2. Q02

    Does it treat hypothyroidism?

    No

    One dog with proven dietary iodine deficiency recovered after a diet change. That case does not mean calcium iodate treats other causes of hypothyroidism, and an ingredient list cannot identify the cause of abnormal thyroid tests.1

  3. Q03

    Can the label show the dose?

    Usually no

    Ingredients are listed by weight without their individual amounts, and the standard guaranteed analysis does not require an iodine figure. If iodine intake needs tracking, ask the maker for measured total iodine in the finished food.7

Who uses it

Brands, best sellers and the company it keeps

Top brands, by foods that list it

  1. Royal Canin 157 / 160
  2. Blue 114 / 186
  3. Hill's 112 / 116
  4. Purina 111 / 185
  5. Nulo 91 / 117
  6. Wellness 72 / 118
  7. Fromm 59 / 67
  8. Stella & Chewy's 45 / 85
  9. Natural Balance 38 / 48
  10. Zignature 36 / 46

Foods that list it / all the brand's recipes we track.

Plus 61 more brands.

Amazon best sellers that list it

  1. #1 Blue Life Protection Formula Adult Chicken and Brown Rice Recipe Dry Dog Food
  2. #2 Purina One SmartBlend Adult Dog Lamb & Rice Formula Dry Dog Food
  3. #3 Purina Pro Plan Adult Complete Essentials Shredded Blend Chicken & Rice Formula Dry Dog Food
  4. #4 Hill’s Science Diet Light Small & Mini Chicken Recipe Dry Dog Food
  5. #5 Blue Life Protection Formula Adult Small Breed Chicken and Brown Rice Recipe Dry Dog Food
  6. #6 Hill’s Science Diet Adult Sensitive Stomach & Skin Chicken Recipe Dry Dog Food
  7. #9 Purina Pro Plan Adult Sensitive Skin & Stomach Salmon & Rice Formula Dry Dog Food
  8. #13 Hill’s Science Diet Adult 1-6 Small Bites Chicken & Barley Recipe Dry Dog Food

Rank on Amazon's dog food best seller list, checked October 2026.

Usually listed with, share of the foods that list it

  1. Mixed Tocopherols 49%
  2. Chicken Fat 44%
  3. Natural Flavor 39%
  4. Chicken 33%
  5. Chicken Meal 33%
  6. Flaxseed 33%
  7. Peas 31%
  8. Brown Rice 28%
  9. Dried Plain Beet Pulp 18%
  10. Sweet Potatoes 17%
  11. Barley 17%
  12. Oatmeal 16%

On the shelf

Foods that list Calcium Iodate

1,628 foods in our catalog list it. These 60 list it highest on the label.

Wysong Fundamentals Dry Dog FoodWysongWysong Fundamentals Dry Dog FoodDry // No. 6 on the labelZignature Essence LIR Landfowl Recipe Food Can Grain-Free Wet Dog FoodZignatureZignature Essence LIR Landfowl Recipe Food Can Grain-Free Wet Dog FoodWet // No. 7 on the labelZignature Essence LIR Ranch Recipe Food Can Grain-Free Wet Dog FoodZignatureZignature Essence LIR Ranch Recipe Food Can Grain-Free Wet Dog FoodWet // No. 7 on the labelZignature Original Food Turkey Formula Grain-Free Wet Dog FoodZignatureZignature Original Food Turkey Formula Grain-Free Wet Dog FoodWet // No. 8 on the labelFromm Four-Star Diner Specials Slow-Cooked Pulled Pork Entrée in Gravy Wet Dog FoodFrommFromm Four-Star Diner Specials Slow-Cooked Pulled Pork Entrée in Gravy Wet Dog FoodWet // No. 8 on the labelWysong Original Diets Healthy Aging Dry Dog FoodWysongWysong Original Diets Healthy Aging Dry Dog FoodDry // No. 8 on the labelZignature Original Food Kangaroo Formula Grain-Free Wet Dog FoodZignatureZignature Original Food Kangaroo Formula Grain-Free Wet Dog FoodWet // No. 9 on the labelFromm Four-Star Diner Classics Charlie’s Chicken Pot Pie Pâté Wet Dog FoodFrommFromm Four-Star Diner Classics Charlie’s Chicken Pot Pie Pâté Wet Dog FoodWet // No. 9 on the labelFirstMate Pacific Ocean Fish Weight Control Formula Grain-Free Dry Dog FoodFirstMateFirstMate Pacific Ocean Fish Weight Control Formula Grain-Free Dry Dog FoodDry // No. 9 on the labelFirstMate Pacific Ocean Fish Large Breed Formula Grain-Free Dry Dog FoodFirstMateFirstMate Pacific Ocean Fish Large Breed Formula Grain-Free Dry Dog FoodDry // No. 9 on the labelWysong Archetype Burgers Freeze-Dried Raw Dog FoodWysongWysong Archetype Burgers Freeze-Dried Raw Dog FoodFreeze-Dried // No. 9 on the labelBixbi Rawbble Grain-Free Freeze-Dried Dog FoodBIXBIBixbi Rawbble Grain-Free Freeze-Dried Dog FoodFreeze-Dried // No. 10 on the label
Show 48 more
Zignature Original Food Lamb Formula Grain-Free Wet Dog FoodZignatureZignature Original Food Lamb Formula Grain-Free Wet Dog FoodWet // No. 9 on the labelZignature Original Food Puppy Formula Grain-Free Wet Dog FoodZignatureZignature Original Food Puppy Formula Grain-Free Wet Dog FoodWet // No. 9 on the labelFirstMate Pacific Ocean Fish Meal Original Formula Grain-Free Dry Dog FoodFirstMateFirstMate Pacific Ocean Fish Meal Original Formula Grain-Free Dry Dog FoodDry // No. 9 on the labelFromm Four-Star Pâté Chicken & Rice Pâté Wet Dog FoodFrommFromm Four-Star Pâté Chicken & Rice Pâté Wet Dog FoodWet // No. 10 on the labelFirstMate Limited Ingredient Diet Free Run Chicken Formula Dry Dog FoodFirstMateFirstMate Limited Ingredient Diet Free Run Chicken Formula Dry Dog FoodDry // No. 10 on the labelFromm Pâté Beef & Barley Pâté Wet Dog FoodFrommFromm Pâté Beef & Barley Pâté Wet Dog FoodWet // No. 10 on the labelFromm Pâté Lamb Pâté Wet Dog FoodFrommFromm Pâté Lamb Pâté Wet Dog FoodWet // No. 10 on the labelFromm Pâté Lamb & Sweet Potato Pâté Wet Dog FoodFrommFromm Pâté Lamb & Sweet Potato Pâté Wet Dog FoodWet // No. 10 on the labelFirstMate Chicken Meal With Blueberries Formula Grain-Free Dry Dog FoodFirstMateFirstMate Chicken Meal With Blueberries Formula Grain-Free Dry Dog FoodDry // No. 10 on the labelGather Free Acres Organic Free-Run Chicken Recipe for Adult Dogs Grain-Free Dry Dog FoodGatherGather Free Acres Organic Free-Run Chicken Recipe for Adult Dogs Grain-Free Dry Dog FoodDry // No. 10 on the labelGravy Train Ground Dinner With Chicken Wet Dog FoodGravy TrainGravy Train Ground Dinner With Chicken Wet Dog FoodWet // No. 11 on the labelWysong Original Diets Senior with Organic Turkey Wet Dog FoodWysongWysong Original Diets Senior with Organic Turkey Wet Dog FoodWet // No. 11 on the labelWysong Original Diets Adult with Organic Chicken Wet Dog FoodWysongWysong Original Diets Adult with Organic Chicken Wet Dog FoodWet // No. 11 on the labelZignature Original Food Zssential Formula Grain-Free Wet Dog FoodZignatureZignature Original Food Zssential Formula Grain-Free Wet Dog FoodWet // No. 11 on the labelFromm Pâté Chicken & Duck Pâté Wet Dog FoodFrommFromm Pâté Chicken & Duck Pâté Wet Dog FoodWet // No. 11 on the labelFromm Pâté Chicken & Sweet Potato Pâté Wet Dog FoodFrommFromm Pâté Chicken & Sweet Potato Pâté Wet Dog FoodWet // No. 11 on the labelFromm Pâté Salmon & Chicken Pâté Wet Dog FoodFrommFromm Pâté Salmon & Chicken Pâté Wet Dog FoodWet // No. 11 on the labelFromm Classic Adult Turkey & Rice Pâté Wet Dog FoodFrommFromm Classic Adult Turkey & Rice Pâté Wet Dog FoodWet // No. 11 on the labelFromm Four-Star Diner Specials Chicken Canine Bleu Entrée in Gravy Wet Dog FoodFrommFromm Four-Star Diner Specials Chicken Canine Bleu Entrée in Gravy Wet Dog FoodWet // No. 11 on the labelFromm Four-Star Diner Classics Paula’s Chicken & Pumpkin Pâté Wet Dog FoodFrommFromm Four-Star Diner Classics Paula’s Chicken & Pumpkin Pâté Wet Dog FoodWet // No. 11 on the labelFromm Classic Puppy Chicken & Salmon Pâté Wet Dog FoodFrommFromm Classic Puppy Chicken & Salmon Pâté Wet Dog FoodWet // No. 11 on the labelFirstMate Kasiks Wild Pacific Ocean Fish Meal Formula Grain-Free Dry Dog FoodFirstMateFirstMate Kasiks Wild Pacific Ocean Fish Meal Formula Grain-Free Dry Dog FoodDry // No. 11 on the labelFirstMate Skoki Dry Dog FoodFirstMateFirstMate Skoki Dry Dog FoodDry // No. 11 on the labelNature’s Recipe Healthy Skin Vegetarian Recipe Dry Dog FoodNature's RecipeNature’s Recipe Healthy Skin Vegetarian Recipe Dry Dog FoodDry // No. 11 on the labelBixbi Liberty Grain-Free Wet Dog FoodBIXBIBixbi Liberty Grain-Free Wet Dog FoodWet // No. 12 on the labelFromm Four-Star Pâté Beef & Sweet Potato Pâté Grain-Free Wet Dog FoodFrommFromm Four-Star Pâté Beef & Sweet Potato Pâté Grain-Free Wet Dog FoodWet // No. 12 on the labelFromm Four-Star Pâté Duck À La Veg Pâté Wet Dog FoodFrommFromm Four-Star Pâté Duck À La Veg Pâté Wet Dog FoodWet // No. 12 on the labelRachael Ray Nutrish Real Chicken & Apple Recipe Whole Health Blend Premium Paté Wet Dog FoodRachael Ray NutrishRachael Ray Nutrish Real Chicken & Apple Recipe Whole Health Blend Premium Paté Wet Dog FoodWet // No. 12 on the labelFromm Four-Star Shredded Pork in Gravy Entrée Wet Dog FoodFrommFromm Four-Star Shredded Pork in Gravy Entrée Wet Dog FoodWet // No. 12 on the labelFromm Four-Star Pâté Turkey, Duck, & Sweet Potato Pâté Wet Dog FoodFrommFromm Four-Star Pâté Turkey, Duck, & Sweet Potato Pâté Wet Dog FoodWet // No. 12 on the labelFromm Four-Star Diner Classics Milo Wet Dog FoodFrommFromm Four-Star Diner Classics Milo Wet Dog FoodWet // No. 12 on the labelInstinct Raw Boost RawBoost+ Mixers Tranquility Recipe Dog Food TopperInstinctInstinct Raw Boost RawBoost+ Mixers Tranquility Recipe Dog Food TopperTopper // No. 12 on the labelRachael Ray Nutrish Limited Ingredient Lamb Meal & Brown Rice Dry Dog FoodRachael Ray NutrishRachael Ray Nutrish Limited Ingredient Lamb Meal & Brown Rice Dry Dog FoodDry // No. 12 on the labelFirstMate Grain Friendly Cage Free Chicken Meal & Oats Formula Small Bites Dry Dog FoodFirstMateFirstMate Grain Friendly Cage Free Chicken Meal & Oats Formula Small Bites Dry Dog FoodDry // No. 12 on the labelFirstMate Kasiks Free Run Chicken Meal Formula Grain-Free Dry Dog FoodFirstMateFirstMate Kasiks Free Run Chicken Meal Formula Grain-Free Dry Dog FoodDry // No. 12 on the labelZignature Inception Chicken Formula Dry Dog FoodZignatureZignature Inception Chicken Formula Dry Dog FoodDry // No. 12 on the labelZignature Original Turkey Formula with Probiotics Grain-Free Dry Dog FoodZignatureZignature Original Turkey Formula with Probiotics Grain-Free Dry Dog FoodDry // No. 12 on the labelZignature Original Pork Formula with Probiotics Grain-Free Dry Dog FoodZignatureZignature Original Pork Formula with Probiotics Grain-Free Dry Dog FoodDry // No. 12 on the labelZignature Original Small Bites Turkey Formula with Probiotics Grain-Free Dry Dog FoodZignatureZignature Original Small Bites Turkey Formula with Probiotics Grain-Free Dry Dog FoodDry // No. 12 on the labelZignature Inception Fish Formula Dry Dog FoodZignatureZignature Inception Fish Formula Dry Dog FoodDry // No. 12 on the labelWellness Core Six Cage-Free Duck Grain-Free Dry Dog FoodWellnessWellness Core Six Cage-Free Duck Grain-Free Dry Dog FoodDry // No. 12 on the labelEagle Pack Power Adult Dry Dog FoodEagle PackEagle Pack Power Adult Dry Dog FoodDry // No. 12 on the labelBixbi Liberty Dry Dog FoodBIXBIBixbi Liberty Dry Dog FoodDry // No. 13 on the labelFromm Four-Star balaya Beef, Vegetable, & Rice Stew Wet Dog FoodFrommFromm Four-Star balaya Beef, Vegetable, & Rice Stew Wet Dog FoodWet // No. 13 on the labelGo! Solutions Sensitivities Shredded Turkey Limited Ingredient Grain-Free Wet Dog FoodGo! SolutionsGo! Solutions Sensitivities Shredded Turkey Limited Ingredient Grain-Free Wet Dog FoodWet // No. 13 on the labelOpen Farm Homestead Turkey Paté Recipe Wet Dog FoodOpen FarmOpen Farm Homestead Turkey Paté Recipe Wet Dog FoodWet // No. 13 on the labelPurina Beneful Freshly Prepared Stews Chicken Dinner with Carrots and Rice in Gravy Wet Dog FoodPurinaPurina Beneful Freshly Prepared Stews Chicken Dinner with Carrots and Rice in Gravy Wet Dog FoodWet // No. 13 on the labelPurina Beneful Freshly Prepared Classics With Lamb, Chopped Kale and Carrots Pate Wet Dog FoodPurinaPurina Beneful Freshly Prepared Classics With Lamb, Chopped Kale and Carrots Pate Wet Dog FoodWet // No. 13 on the label

Sources

What we read

Checked September 1, 2026.

  1. 1 Case Report: Diet-associated iodine-deficiency goitrous hypothyroidism in a dog: a longitudinal clinical, endocrine, and ultrasonographic evaluation Frontiers in Veterinary Science, 2026 // Journal
  2. 2 Morphologic Changes in the Thyroid Glands of Puppies Fed a High-Iodine Commercial Diet International Journal of Applied Research in Veterinary Medicine, 2003 // Journal
  3. 3 Assessment of the feed additives consisting of potassium iodide and calcium iodate anhydrous for all animal species for the renewal of their authorisation (AJAY EUROPE SARL) EFSA Journal, 2025 // Journal
  4. 4 AAFCO DOG AND CAT FOOD AAFCO, 2013 // Regulator
  5. 5 Process for the preparation of crystalline calcium iodate Google Patents, 1983 // Database
  6. 6 Iodine sources EMFEMA, n.d. // Industry
  7. 7 Reading Labels AAFCO, n.d. // Regulator
An ingredient on its own tells you very little. What matters is how much of it there is and where it sits in the list. That is why we weigh the top five rather than reacting to any single name further down. Back to the wiki

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