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

Thyroid and Testosterone and Bones and Muscles

1380 capsules across 53 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.

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.

Bones. Ingredients here hold register claims relating to the maintenance of normal bones, quoted exactly on their pages. Weight-bearing exercise and dietary calcium are the foundations, and the Royal Osteoporosis Society is the specialist charity for anything further.

Muscles. Ingredients here hold register claims relating to normal muscle function or muscle protein, quoted exactly on their pages. Resistance exercise and overall protein intake are the fundamentals the claims assume; the NHS exercise guidance below is a good starting point.

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

2 authorised claims · 334 capsules · ingredient page
  • “Magnesium contributes to the maintenance of normal bones” · Bones
  • “Magnesium contributes to normal muscle function” · Muscles

All 334 magnesium capsules

Vitamin C

1 authorised claim · 332 capsules · ingredient page
  • “Vitamin C contributes to normal collagen formation for the normal function of bones” · Bones

All 332 vitamin c capsules

Zinc

2 authorised claims · 249 capsules · ingredient page
  • “Zinc contributes to the maintenance of normal bones” · Bones
  • “Zinc contributes to the maintenance of normal testosterone levels in the blood” · Testosterone

Not authorised for thyroid or muscles: the register refused 2 claims there.

All 249 zinc capsules

Vitamin D

5 authorised claims · 232 capsules · ingredient page
  • “Vitamin D contributes to the maintenance of normal bones” · Bones
  • “Vitamin D is needed for normal growth and development of bone in children.” · Bones
  • “Vitamin D helps to reduce the risk of falling associated with postural instability and muscle weakness. Falling is a risk factor for bone fractures among men and women 60 years of age and older.” · Bones
  • “Vitamin D contributes to the maintenance of normal muscle function” · Muscles
  • and 1 more on the ingredient page

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

All 232 vitamin d capsules

Vitamin K

1 authorised claim · 106 capsules · ingredient page
  • “Vitamin K contributes to the maintenance of normal bones” · Bones

All 106 vitamin k capsules

Calcium

4 authorised claims · 96 capsules · ingredient page
  • “Calcium helps to reduce the loss of bone mineral in post-menopausal women. Low bone mineral density is a risk factor for osteoporotic bone fractures” · Bones
  • “Calcium is needed for normal growth and development of bone in children.” · Bones
  • “Calcium is needed for the maintenance of normal bones” · Bones
  • “Calcium contributes to normal muscle function” · Muscles

All 96 calcium capsules

Selenium

1 authorised claim · 95 capsules · ingredient page
  • “Selenium contributes to the normal thyroid function” · Thyroid

All 95 selenium capsules

Iodine

1 authorised claim · 45 capsules · ingredient page
  • “Iodine contributes to the normal production of thyroid hormones and normal thyroid function” · Thyroid

All 45 iodine capsules

Manganese

1 authorised claim · 32 capsules · ingredient page
  • “Manganese contributes to the maintenance of normal bones” · Bones

All 32 manganese capsules

Potassium

1 authorised claim · 32 capsules · ingredient page
  • “Potassium contributes to normal muscle function” · Muscles

All 32 potassium capsules

creatine

2 authorised claims · 20 capsules · ingredient page
  • “Daily creatine consumption can enhance the effect of resistance training on muscle strength in adults over the age of 55.” · Muscles
  • “Creatine increases physical performance in successive bursts of short-term, high intensity exercise” · Muscles

Not authorised for muscles: the register refused 3 claims there.

All 20 creatine capsules

Phosphorus

2 authorised claims · 3 capsules · ingredient page
  • “Phosphorus contributes to the maintenance of normal bones” · Bones
  • “Phosphorus is needed for the normal growth and development of bone in children” · Bones

Protein

4 authorised claims · 1 capsule · ingredient page
  • “Protein contributes to the maintenance of normal bones” · Bones
  • “Protein contributes to a growth in muscle mass” · Muscles
  • “Protein contributes to the maintenance of muscle mass” · Muscles
  • “Protein is needed for normal growth and development of bone in children.” · Bones

Assessed by the register and not authorised

The register looked at claims for these relating to thyroid and testosterone and bones and muscles 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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