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Say what you want help with. The finder shows what the GB register lets any seller claim for it, what the register assessed and refused, and the cheapest capsules per capsule for each ingredient. It quotes; it never advises.

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Where the register allows less than sellers suggest

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Name it and the finder says whether the register authorises any claim for it for your goals, or refused one, or has never assessed it.

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Seller-stated only: vegan means the seller says vegan.

Metabolism and Fertility and Thyroid and Digestion

1431 capsules across 55 ingredients

Metabolism. The register's phrase is 'contributes to normal energy-yielding metabolism', and many everyday vitamins and minerals hold it. It is not a claim about weight or about feeling energetic, which is why this goal sits apart from Weight and from Tiredness and fatigue. Wording is quoted exactly on each ingredient page.

Fertility. Ingredients here hold register claims relating to fertility and reproduction, quoted exactly. UK guidance on folic acid before and during early pregnancy is the best-established nutritional advice in this area, and Fertility Network UK below offers wider support.

Thyroid. Only iodine and selenium hold authorised register wording about the thyroid, quoted exactly on their pages. Thyroid conditions are diagnosed and managed by a GP, and the British Thyroid Foundation is the specialist charity.

Digestion. The register authorises specific wording about digestion for a few nutrients, quoted exactly on their pages, and refused most of the probiotic and gut wording sellers reach for. The split below is the honest picture. Persistent digestive symptoms are a matter for a GP, and Guts UK is the specialist charity.

Nothing here is medical advice. The wording is the GB register's, quoted exactly; whether a product qualifies to use it is the seller's responsibility. Speak to a GP or pharmacist before taking a supplement, especially if you are pregnant, take medicines or have a diagnosed condition. Wording from the GB nutrition and health claims register; mapping reviewed 4 September 2026.

Holds an authorised claim

Magnesium

1 authorised claim · 334 capsules · ingredient page
  • “Magnesium contributes to normal energy-yielding metabolism” · Metabolism

Not authorised for metabolism or fertility: the register refused 3 claims there.

All 334 magnesium capsules

Vitamin C

1 authorised claim · 332 capsules · ingredient page
  • “Vitamin C contributes to normal energy-yielding metabolism” · Metabolism

All 332 vitamin c capsules

Zinc

5 authorised claims · 249 capsules · ingredient page
  • “Zinc contributes to normal fertility and reproduction” · Fertility
  • “Zinc contributes to normal carbohydrate metabolism” · Metabolism
  • “Zinc contributes to normal macronutrient metabolism” · Metabolism
  • “Zinc contributes to normal metabolism of fatty acids” · Metabolism
  • and 1 more on the ingredient page

Not authorised for thyroid: the register refused 1 claim there.

All 249 zinc capsules

Vitamin B6

3 authorised claims · 185 capsules · ingredient page
  • “Vitamin B6 contributes to normal energy-yielding metabolism” · Metabolism
  • “Vitamin B6 contributes to normal homocysteine metabolism” · Metabolism
  • “Vitamin B6 contributes to normal protein and glycogen metabolism” · Metabolism

All 185 vitamin b6 capsules

Vitamin B12

2 authorised claims · 163 capsules · ingredient page
  • “Vitamin B12 contributes to normal energy-yielding metabolism” · Metabolism
  • “Vitamin B12 contributes to normal homocysteine metabolism” · Metabolism

All 163 vitamin b12 capsules

Folate

2 authorised claims · 138 capsules · ingredient page
  • “Folate contributes to maternal tissue growth during pregnancy” · Fertility
  • “Folate contributes to normal homocysteine metabolism” · Metabolism

All 138 folate capsules

Biotin

2 authorised claims · 124 capsules · ingredient page
  • “Biotin contributes to normal energy-yielding metabolism” · Metabolism
  • “Biotin contributes to normal macronutrient metabolism” · Metabolism

All 124 biotin capsules

Calcium

2 authorised claims · 96 capsules · ingredient page
  • “Calcium contributes to normal energy-yielding metabolism” · Metabolism
  • “Calcium contributes to the normal function of digestive enzymes” · Digestion

Not authorised for metabolism: the register refused 1 claim there.

All 96 calcium capsules

Selenium

2 authorised claims · 95 capsules · ingredient page
  • “Selenium contributes to normal spermatogenesis” · Fertility
  • “Selenium contributes to the normal thyroid function” · Thyroid

All 95 selenium capsules

Iron

1 authorised claim · 87 capsules · ingredient page
  • “Iron contributes to normal energy-yielding metabolism” · Metabolism

Not authorised for metabolism: the register refused 1 claim there.

All 87 iron capsules

Chromium

1 authorised claim · 62 capsules · ingredient page
  • “Chromium contributes to normal macronutrient metabolism” · Metabolism

Not authorised for metabolism: the register refused 2 claims there.

All 62 chromium capsules

Copper

1 authorised claim · 58 capsules · ingredient page
  • “Copper contributes to normal energy-yielding metabolism” · Metabolism

All 58 copper capsules

Vitamin A

1 authorised claim · 54 capsules · ingredient page
  • “Vitamin A contributes to normal iron metabolism” · Metabolism

All 54 vitamin a capsules

Choline

2 authorised claims · 49 capsules · ingredient page
  • “Choline contributes to normal homocysteine metabolism” · Metabolism
  • “Choline contributes to normal lipid metabolism” · Metabolism

All 49 choline capsules

Niacin

1 authorised claim · 46 capsules · ingredient page
  • “Niacin contributes to normal energy-yielding metabolism” · Metabolism

All 46 niacin capsules

Iodine

2 authorised claims · 45 capsules · ingredient page
  • “Iodine contributes to normal energy-yielding metabolism” · Metabolism
  • “Iodine contributes to the normal production of thyroid hormones and normal thyroid function” · Thyroid

All 45 iodine capsules

Pantothenic Acid

2 authorised claims · 36 capsules · ingredient page
  • “Pantothenic acid contributes to normal energy-yielding metabolism” · Metabolism
  • “Pantothenic acid contributes to normal synthesis and metabolism of steroid hormones, vitamin D and some neurotransmitters” · Metabolism

All 36 pantothenic acid capsules

Riboflavin

2 authorised claims · 36 capsules · ingredient page
  • “Riboflavin contributes to normal energy-yielding metabolism” · Metabolism
  • “Riboflavin contributes to the normal metabolism of iron” · Metabolism

All 36 riboflavin capsules

Manganese

1 authorised claim · 32 capsules · ingredient page
  • “Manganese contributes to normal energy-yielding metabolism” · Metabolism

All 32 manganese capsules

Activated Charcoal

1 authorised claim · 17 capsules · ingredient page
  • “Activated charcoal contributes to reducing excessive flatulence after eating” · Digestion

Not authorised for digestion: the register refused 1 claim there.

All 17 activated charcoal capsules

Molybdenum

1 authorised claim · 15 capsules · ingredient page
  • “Molybdenum contributes to normal sulphur amino acid metabolism” · Metabolism

Not authorised for metabolism: the register refused 1 claim there.

All 15 molybdenum capsules

Chloride

1 authorised claim · 5 capsules · ingredient page
  • “Chloride contributes to normal digestion by production of hydrochloric acid in the stomach” · Digestion

All 5 chloride capsules

Thiamine

1 authorised claim · 5 capsules · ingredient page
  • “Thiamine contributes to normal energy-yielding metabolism” · Metabolism

All 5 thiamine capsules

sugar beet fibre

1 authorised claim · 4 capsules · ingredient page
  • “Sugar beet fibre contributes to an increase in faecal bulk” · Digestion

Not authorised for digestion: the register refused 2 claims there.

All 4 sugar beet fibre capsules

Lactase enzyme

1 authorised claim · 3 capsules · ingredient page
  • “Lactase enzyme improves lactose digestion in individuals who have difficulty digesting lactose” · Digestion

All 3 lactase enzyme capsules

Phosphorus

1 authorised claim · 3 capsules · ingredient page
  • “Phosphorus contributes to normal energy-yielding metabolism” · Metabolism

Betaine

1 authorised claim · 2 capsules · ingredient page
  • “Betaine contributes to normal homocysteine metabolism” · Metabolism

Assessed by the register and not authorised

The register looked at claims for these relating to metabolism and fertility and thyroid and digestion and turned them down. Sellers may not make them. Prices are shown for ingredients you named; the rest link to their register page.

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