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Potassium iodide

Also called potassium iodide, kelp.

The best price per 150 µg iodine and per month across 3 UK retailers, and where to buy it cheapest. A unit for comparing, not advice.

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. Products that combine iodine with other ingredients 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.

Prices last checked: . 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.

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

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Iodine, Potassium iodide: products ranked by price per 150 µg iodine
RankProductPer 150 µg iodinePer monthLastsBuyHow it is worked out
1
Ancient Purity Lugol's Iodine
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 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
WeightWorld Iodine Tablets
Iodine TabletsWeightWorld · 365 servings · 400 µg a servingDetails and price historyAdd to my stack
1p31p2.7 years£9.99View at WeightWorld (opens in a new tab)Free delivery over £35.00, otherwise £1.99AmazonFind 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
  • £9.99 ÷ 146 mg × 150 µg = 1.03p 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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3
Codeage Iodine + - 2 fl oz
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 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
MaryRuth's Iodine Drops - Unflavoured - 1 oz
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 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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5
KIKI Health Ionic Iodine Liquid Concentrate
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 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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6
Nature's Best Iodine 150µg - for Normal Thyroid, Cognitive and Neurological Function
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 delivery over £20.00, otherwise £2.50AmazonFind 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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7
Pure Encapsulations Iodine (potassium iodide)
Iodine (potassium iodide)Healf · 60 capsules · 60 servings · 225 µg a servingDetails and price historyAdd to my stackclaimed: vegetarian
9p£2.673 months£8.00View at Healf (opens in a new tab)Free 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
  • £8.00 ÷ 13.5 mg × 150 µg = 8.89p 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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8
Pure Encapsulations Iodine & Tyrosine
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 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