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Home › Minerals › Iodine

Potassium iodide

Also called potassium iodide, kelp.

Cheapest potassium iodide today: under 1p per 150 µg iodine at Healf, of 13 products at 4 shops. Checked 15 November 2026.

How much iodine is in your tablet?

The best price per 150 µg iodine and per month across 4 UK retailers, and where to buy it cheapest. A unit for comparing, not advice.

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Comparing iodine

Labels give iodine in micrograms, and some in milligrams: 150 µg is 150 mcg. We put every product in one unit before pricing it. Iodine comes as potassium iodide and kelp, and each form has its own table, because someone buying one would not usually take another as a like-for-like substitute. A product with one other ingredient is ranked here with an “also contains” note; products that combine iodine with several others are listed separately, because their price buys more than iodine. 150 µg is our unit for comparing prices, not a dose to take: the label’s directions and a pharmacist decide that.

Most prices last checked: ; an older price shows its own date. Ranked purely by price per 150 µg iodine — a comparison unit, not a recommendation. We earn commission when you buy through these links; it never affects the order.

Every one of the 10 cheapest links on this page earns us commission; the order is price alone. Shop by shop

Compared at 150 µg. Enter the amount you take to see your own costs.

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Potassium iodide: products ranked by price per 150 µg iodine
RankProductPer 150 µg iodinePer monthLastsBuyHow it is worked out
1
Cheapest per doseLugol's IodineHealf · 50 ml · 450 servings · 12.5 mg a servingDetails and price historyAdd to my stack
under 1p2p102.7 years£22.49View at Healf (opens in a new tab)Free UK delivery over £50.00, otherwise £3.99AmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 450 (as stated on the label)
  • In the pack: 450 × 12.5 mg = 5,625 mg
  • £22.49 ÷ 5,625 mg × 150 µg = 0.06p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “50ml”
  • servings stated “Servings per container: 450”
  • amount per serving “Iodine ; 12.5mg ; 8333%”
  • potassium iodide “Potassium Iodide ; 25mg”

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2
Iodine Liquid | Extra Strong (1525mcg Per Serving) | Pure IOSOL Iodine in a Convenient 15ml Bottle (375 Servings) | Ammonium IodideMetabolics · Amazon · 375 drops · 375 servings · 1.75 mg a servingDetails and price historyAdd to my stackclaimed: veganclaimed: vegetarianclaimed: gluten-free
1p18p12 years£25.70View at Amazon (opens in a new tab)Free delivery over £35.00; below that, not knownAmazon price as of 15 Nov 2026, 05:55 · Details
Show the working
  • Servings: 375 ÷ 1 per serving = 375
  • In the pack: 375 × 1.75 mg = 657.8 mg
  • £25.70 ÷ 657.8 mg × 150 µg = 0.586p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “1 serving = 1 drop | 375 servings per container”
  • servings stated “375 servings per container”
  • units per serving “Serving Size: 1 Drop”
  • amount per serving “Iodine 1754 mcg”

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3
Iodine + - 2 fl ozHealf · 1,200 servings · 250 µg a servingDetails and price historyAdd to my stackclaimed: vegan
1p34p5.5 years£22.49View at Healf (opens in a new tab)Free UK delivery over £50.00, otherwise £3.99AmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 1200 (as stated on the label)
  • In the pack: 1200 × 250 µg = 300 mg
  • £22.49 ÷ 300 mg × 150 µg = 1.12p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • servings stated “Servings Per Container: 1200”
  • units per serving “Serving Size: 1 Drop”
  • amount per serving “Iodine (as Potassium Iodide) ; 250 mcg”

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4
Iodine TabletsWeightWorld · 365 servings · 400 µg a servingDetails and price historyAdd to my stack
1p40p2.7 years£12.99View at WeightWorld (opens in a new tab)Free delivery over £35.00, otherwise £1.99 · 2–3 working daysAmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 365 (as stated on the label)
  • In the pack: 365 × 400 µg = 146 mg
  • £12.99 ÷ 146 mg × 150 µg = 1.33p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • servings stated “Servings per Container: 365”
  • units per serving “Serving Size: 1 Tablet”
  • amount per serving “Iodine (as Potassium Iodide) ; 400 mcg”

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5
Iodine Plus Drops 150 mcg 2 fl oz | Thyroid, Energy & Metabolism Support - Iodine & Potassium Iodide Liquid Formula - UnflavoredLife-Flo · Amazon · 59 ml · 468.3 servings · 150 µg a servingDetails and price historyAdd to my stackUnflavored
2p48p1.3 years£7.43View at Amazon (opens in a new tab)Free delivery over £35.00; below that, not knownAmazon price as of 15 Nov 2026, 05:55 · Details
Show the working
  • Servings: 59 ÷ 0.126 per serving = 468.3
  • In the pack: 468.3 × 150 µg = 70.2 mg
  • £7.43 ÷ 70.2 mg × 150 µg = 1.59p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “2 FL OZ (59 mL)”
  • servings stated “Servings Per Container About 450”
  • units per serving “Serving Size 3 Drops (0.126 mL)”
  • amount per serving “Iodine (as Potassium Iodide) 150 mcg”

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6
Iodine Drops - Unflavoured - 1 ozHealf · 450 servings · 250 µg a servingDetails and price historyAdd to my stackUnflavoured
2p63p2.1 years£15.65View at Healf (opens in a new tab)Free UK delivery over £50.00, otherwise £3.99AmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 450 (as stated on the label)
  • In the pack: 450 × 250 µg = 112.5 mg
  • £15.65 ÷ 112.5 mg × 150 µg = 2.09p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • servings stated “Servings Per Container: 450”
  • units per serving “2 Drops (0.07mL)”
  • amount per serving “Iodine (as Potassium Iodide) ; 250 mcg”

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7
Ionic Iodine Liquid ConcentrateHealf · 50 ml · 384.6 servings · 300 µg a servingDetails and price historyAdd to my stack
3p76p2.1 years£19.50View at Healf (opens in a new tab)Free UK delivery over £50.00, otherwise £3.99AmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 50 ÷ 0.13 per serving = 384.6
  • In the pack: 384.6 × 300 µg = 115.4 mg
  • £19.50 ÷ 115.4 mg × 150 µg = 2.54p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “50ml”
  • units per serving “take 2 drops (0.13ml) daily”
  • amount per serving “300 mcg of iodine per serving”

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8
Best value under 6 months' supplyIodine 150µg - for Normal Thyroid, Cognitive and Neurological Function180 tablets · 180 servings · 150 µg a servingDetails and price historyAdd to my stackclaimed: veganclaimed: vegetarian
4p£1.256 months£7.50View at Lamberts Healthcare (Nature's Best) (opens in a new tab)Free UK delivery over £20.00, otherwise £2.50 · usually 3–4 working days, up to 10 at busy timesAmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 180 ÷ 1 per serving = 180
  • In the pack: 180 × 150 µg = 27 mg
  • £7.50 ÷ 27 mg × 150 µg = 4.17p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “Specifications: 180 Tablets”
  • amount per serving “each one of our tablets supplies 150µg of free elemental iodine in the form of potassium iodide”

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9
Iodine 150mcg 180 Tablets - Supports Thyroid Function - Small Easy-Swallow Tablets - VeganLamberts · Amazon · 180 tablets · 180 servings · 150 µg a servingDetails and price historyAdd to my stackclaimed: veganclaimed: vegetarian
5p£1.656 months£9.89View at Amazon (opens in a new tab)Free delivery over £35.00; below that, not knownAmazon price as of 15 Nov 2026, 05:55 · Details
Show the working
  • Servings: 180 ÷ 1 per serving = 180
  • In the pack: 180 × 150 µg = 27 mg
  • £9.89 ÷ 27 mg × 150 µg = 5.49p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “180 Tablets”
  • units per serving “tomar de 1 a 2 tabletas”
  • amount per serving “Por tableta: Yodo 150 mcg”

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10
Iodine 150mcg Tablets | Iodine Food Supplement | Oxford Vitality | 120 TabletsOv OXFORD VITALITY · Amazon · 120 tablets · 120 servings · 150 µg a servingDetails and price historyAdd to my stack
7p£2.004 months£7.99View at Amazon (opens in a new tab)Free delivery over £35.00; below that, not knownAmazon price as of 15 Nov 2026, 05:55 · Details
Show the working
  • Servings: 120 ÷ 1 per serving = 120
  • In the pack: 120 × 150 µg = 18 mg
  • £7.99 ÷ 18 mg × 150 µg = 6.66p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “120 Tablets”
  • units per serving “Serving Size: 1 Tablet”
  • amount per serving “providing 150mcg elemental iodine) 150mcg 100%”
  • compound mass “from 196mcg Potassium Iodide”

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11
NaturesPlus Potassium Iodide 150 mcg - Iodine Tablets - Metabolism, Cognitive Functions, Skin, Energy - Vegetarian, Gluten FreeNature's Plus · Amazon · 100 tablets · 100 servings · 150 µg a servingDetails and price historyAdd to my stackTesting claimed on labelclaimed: vegetarianclaimed: gluten-free
10p£3.003 months£9.99View at Amazon (opens in a new tab)Free delivery over £35.00; below that, not knownAmazon price as of 15 Nov 2026, 05:55 · Details
Show the working
  • Servings: 100 ÷ 1 per serving = 100
  • In the pack: 100 × 150 µg = 15 mg
  • £9.99 ÷ 15 mg × 150 µg = 9.99p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • testing claim “third-party tested”
  • pack units “100 Tablets”
  • units per serving “Serving Size 1 Tablet”
  • amount per serving “Iodine (as potassium iodide) 150 mcg”

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12
Iodine (Potassium Iodide) 225, 60 Vegetarian Capsules | Supports Normal Thyroid Function & Metabolism, 225ug Iodine as Potassium Iodide, Aids Cognitive FunctionHealf · 60 capsules · 60 servings · 225 µg a servingDetails and price historyAdd to my stackclaimed: vegetarian
12p£3.503 months£10.50View at Healf (opens in a new tab)Free UK delivery over £50.00, otherwise £3.99
Show the working
  • Servings: 60 ÷ 1 per serving = 60
  • In the pack: 60 × 225 µg = 13.5 mg
  • £10.50 ÷ 13.5 mg × 150 µg = 11.7p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “60 caps”
  • servings stated “Servings Per Container: 60”
  • units per serving “Serving Size: 1 capsule”
  • amount per serving “Iodine (as Potassium Iodide) ; 225 mcg”

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13
Iodine (Potassium Iodide) 225, 60 Vegetarian Capsules | Supports Normal Thyroid Function & Metabolism, 225ug Iodine as Potassium Iodide, Aids Cognitive FunctionAmazon · 60 capsules · 60 servings · 225 µg a servingDetails and price historyAdd to my stackclaimed: vegetarianHPMC capsule, the listing says
15p£4.583 months£13.75View at Amazon (opens in a new tab)Free delivery over £35.00; below that, not knownAmazon price as of 15 Nov 2026, 05:55 · Details
Show the working
  • Servings: 60 ÷ 1 per serving = 60
  • In the pack: 60 × 225 µg = 13.5 mg
  • £13.75 ÷ 13.5 mg × 150 µg = 15.3p per 150 µg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “60 Vegetarian Capsules”
  • servings stated “Servings per container 60”
  • units per serving “Serving size 1 capsule”
  • amount per serving “Iodine (as potassium iodide) 225 mcg 150%”

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14
Iodine & TyrosineHealf · 60 capsules · 60 servings · 225 µg a servingDetails and price historyAdd to my stackalso contains tyrosineclaimed: vegetarian
31p£9.413 months£28.23View at Healf (opens in a new tab)Free UK delivery over £50.00, otherwise £3.99AmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 60 ÷ 1 per serving = 60
  • In the pack: 60 × 225 µg = 13.5 mg
  • £28.23 ÷ 13.5 mg × 150 µg = 31.4p per 150 µg
  • Amount per serving: stated on the label.
  • Also contains: tyrosine. The price counts the iodine only.
What the retailer's listing says
  • pack units “60 caps”
  • servings stated “Servings Per Container: 60”
  • units per serving “Serving Size: 1 capsule”
  • amount per serving “Iodine (as Potassium Iodide) ; 225 mcg ; 150%”

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By shop

Each shop's iodine products, with where its cheapest sits in the market.

How we work out these prices

We count the elemental iodine a product provides, not the weight of the whole compound it comes in. If a label states the iodine amount, we use it. If it only gives the compound's weight, we estimate using a published conversion factor and mark the figure “estimated”. If we cannot tell which the number means, the product is left out until it can be confirmed.

Conversion factor used when only the compound weight is given: potassium iodide 76.4%. How we chose these.

Our full method · All iodine forms