Iodine is an essential trace element the body cannot produce itself. It is indispensable for the synthesis of the thyroid hormones T3 and T4, which regulate the basal metabolism of every cell in the body. Without enough iodine, the thyroid cannot produce these hormones properly.

EFSA-authorised health claims for iodine include: normal thyroid function (iodine is a direct building block of T3 and T4), normal energy-yielding metabolism (thyroid hormones regulate energy expenditure), normal cognitive function (the brain is particularly sensitive to iodine status), normal function of the nervous system, maintenance of normal skin, and normal growth in children. Iodine deficiency remains the world’s leading cause of preventable cognitive impairment.

Several groups are particularly at risk: vegetarians and vegans (seafood is the primary dietary source of iodine, and without it intake is often insufficient), pregnant and breastfeeding women (iodine needs increase by 50% during pregnancy — 200-250 µg/day instead of 150 µg — for the foetus’s neurological development), people who eat little iodised salt (low-salt diets, non-iodised sea salt or Himalayan pink salt contain no added iodine), endurance athletes (sweating causes iodine losses), and people living far from the coast (a landlocked diet is naturally low in iodine).

Signs of iodine deficiency are often subtle: persistent fatigue, feeling the cold, unexplained weight gain, difficulty concentrating, dry skin, constipation. A TSH and free T4 blood test can check thyroid status.

The drop format offers several advantages over iodine tablets or capsules: ultra-precise dosing (each drop delivers a defined amount of iodine, allowing you to adjust to your exact needs), possible sublingual absorption for a rapid uptake, easy to take (diluted in a glass of water or directly under the tongue), economical use, and an easily adjustable dose for children. Dr Jacob’s is a German laboratory known for scientifically formulated minerals and vitamins with a constant focus on bioavailability and purity.

Follow the manufacturer’s recommendations on the bottle. The drop format allows precise adjustment. Recommended pairings: selenium (an essential cofactor for T4-to-T3 conversion — without enough selenium, iodine alone is not enough for optimal thyroid function), zinc (involved in thyroid hormone synthesis), iron (iron deficiency disrupts thyroid metabolism), and vitamin D3 (often deficient in people with hypothyroidism).

Not recommended in cases of hyperthyroidism or autoimmune thyroid disease (Hashimoto’s, Graves’ disease) without medical advice. Do not exceed 600 µg/day without medical supervision. Consult a doctor if you take thyroid medication.

Does iodine cause weight gain or loss?

Iodine itself does not directly cause weight gain or loss. However, correcting an iodine deficiency restores normal thyroid function, which can help normalise metabolism and support weight management.

Can iodine be taken alongside magnesium?

Yes, there is no interaction between iodine and magnesium — both can be taken on the same day, even at the same meal if needed.

Herba Barona is an independent specialist supplement shop in the heart of Paris — established in 2006. What you order is genuinely on our shelves: we ship from our own stock, with no dropshipping and no long waits.

Visit us at 10 rue Théophile Roussel, Paris 12 — or use Click & Collect and pick up your order in-store. We also deliver across France and Europe. Friendly, expert advice in English from our team.

Where is the shop?

Herba Barona is at 10 rue Théophile Roussel, 75012 Paris — a two-minute walk from Ledru-Rollin (line 8), close to Bastille. Open Tuesday to Saturday, 9:30 am–6:30 pm.

Can I order online or collect in store?

Yes. We ship across France and Europe under the same conditions as our French store, or choose Click & Collect to pick up your order for free at our Paris shop.