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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.

  • None yet. Type an ingredient in the box above, for example “magnesium” or “turmeric”.

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

Thyroid and Immunity and Sleep and Testosterone

1276 capsules across 40 ingredients

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.

Immunity. This page gathers ingredients whose GB register claims relate to the normal function of the immune system, with the exact authorised wording quoted on each ingredient page. Anything not authorised may not be claimed by sellers, and we quote that status too. A balanced diet, sleep and vaccination advice from the NHS come before any capsule.

Sleep. Almost nothing holds an authorised GB register claim about sleep, and that absence is worth knowing in itself: sellers may not claim it either. Ingredients people discuss for sleep appear below with their actual register status, and The Sleep Charity offers evidence-based sleep advice.

Testosterone. Only a small number of ingredients hold register claims mentioning testosterone, and this page quotes them exactly. Claims in this category are heavily marketed well beyond what the register authorises; the split below shows the line.

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

Vitamin C

2 authorised claims · 68 capsules · ingredient page
  • “Vitamin C contributes to maintain the normal function of the immune system during and after intense physical exercise” · Immunity
  • “Vitamin C contributes to the normal function of the immune system” · Immunity

All 68 vitamin c capsules

Vitamin D

2 authorised claims · 60 capsules · ingredient page
  • “Vitamin D contributes to the normal function of the immune system” · Immunity
  • “Vitamin D contributes to the normal function of the immune system in children.” · Immunity

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

All 60 vitamin d capsules

Zinc

2 authorised claims · 54 capsules · ingredient page
  • “Zinc contributes to the normal function of the immune system” · Immunity
  • “Zinc contributes to the maintenance of normal testosterone levels in the blood” · Testosterone

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

All 54 zinc capsules

Vitamin B6

1 authorised claim · 43 capsules · ingredient page
  • “Vitamin B6 contributes to the normal function of the immune system” · Immunity

All 43 vitamin b6 capsules

Vitamin B12

1 authorised claim · 34 capsules · ingredient page
  • “Vitamin B12 contributes to the normal function of the immune system” · Immunity

All 34 vitamin b12 capsules

Folate

1 authorised claim · 30 capsules · ingredient page
  • “Folate contributes to the normal function of the immune system” · Immunity

All 30 folate capsules

Iron

1 authorised claim · 17 capsules · ingredient page
  • “Iron contributes to the normal function of the immune system” · Immunity

All 17 iron capsules

Selenium

2 authorised claims · 16 capsules · ingredient page
  • “Selenium contributes to the normal function of the immune system” · Immunity
  • “Selenium contributes to the normal thyroid function” · Thyroid

All 16 selenium capsules

Copper

1 authorised claim · 13 capsules · ingredient page
  • “Copper contributes to the normal function of the immune system” · Immunity

All 13 copper capsules

Vitamin A

1 authorised claim · 9 capsules · ingredient page
  • “Vitamin A contributes to the normal function of the immune system” · Immunity

All 9 vitamin a capsules

Iodine

1 authorised claim · 8 capsules · ingredient page
  • “Iodine contributes to the normal production of thyroid hormones and normal thyroid function” · Thyroid

All 8 iodine capsules

Melatonin

2 authorised claims · ingredient page
  • “Melatonin contributes to the alleviation of subjective feelings of jet lag” · Sleep
  • “Melatonin contributes to the reduction of time taken to fall asleep” · Sleep

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

Melatonin is prescription only in the UK, so no merchant here lists it. It stays for information.

Assessed by the register and not authorised

The register looked at claims for these relating to thyroid and immunity and sleep and testosterone 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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