Thyroid Support™ | Iodine 450mcg, Guggul 10% Guggulsterones, L-Tyrosine, Active B2 & Thyroid Cofactor Minerals | 60 Vegetarian Capsules

Thyroid Support™ — Vegetarian, Glandular-Free Thyroid Formula with Iodine 450mcg, Guggul 10% Guggulsterones, L-Tyrosine, Active B2 & Thyroid Cofactor Minerals

Thyroid Support™ is Priority One's comprehensive vegetarian thyroid support formula — providing the essential nutritional cofactors for normal thyroid hormone synthesis and thyroid gland function without any thyroid glandular tissue. It is the ideal choice for individuals who prefer a plant-based, glandular-free thyroid support approach or who are sensitive to glandular products.*

100% vegetarian capsule (hypromellose). No glandular ingredients.

Serving size is 2 vegetarian capsules, 30 servings per container (60 capsules).

What's inside and why it matters

Thiamine HCl (Vitamin B1, 30mg, 2,500% DV) — A high-potency B1 dose supporting normal cellular energy metabolism. Thyroid hormones regulate the rate of cellular energy production — B1 is a primary cofactor for pyruvate dehydrogenase and the Krebs cycle enzymes most directly controlled by thyroid hormone status.*

Riboflavin 5 Sodium Phosphate (Vitamin B2, 50mg, 3,846% DV) — The active coenzyme form of riboflavin — the most bioavailable B2 form that does not require hepatic phosphorylation before use. This is a key differentiator in Thyroid Support vs Thyroid Plus™. Riboflavin 5 Sodium Phosphate operates directly as the FAD and FMN cofactors for cellular energy metabolism — and critically, as the essential cofactor for thyroid peroxidase (TPO), the enzyme responsible for the oxidation and organification of iodide into thyroid hormone synthesis. Normal TPO function is the rate-limiting step in thyroid hormone production.*

Niacin/Niacinamide 50/50 (52mg NE, 325% DV) — A blend of free niacin and non-flushing niacinamide supporting normal NAD+ synthesis for cellular energy production and normal thyroid gland cellular maintenance.*

Iodine as Potassium Iodide (450mcg, 300% DV) — The most important mineral for normal thyroid hormone synthesis — and the key ingredient that distinguishes Thyroid Support from Thyroid Plus™. Iodine is the essential element incorporated into both T4 (4 iodine atoms) and T3 (3 iodine atoms) during thyroid hormone synthesis. Without adequate iodine, thyroid hormone production is impossible regardless of all other nutritional cofactors.*

At 450mcg (300% of the daily value), Thyroid Support provides a meaningful iodine dose substantially above the minimum daily requirement — addressing the widely prevalent iodine insufficiency associated with reduced use of iodised salt, low seafood intake, and soil iodine depletion in many regions. Adequate iodine is one of the most fundamental requirements for normal thyroid function.*

Magnesium as Magnesium Aspartate Oxide (40mg, 10% DV) — A multi-form magnesium blend supporting normal thyroid hormone deiodination (T4 to T3 conversion via deiodinase enzymes) and normal energy metabolism in thyroid-responsive tissues.*

Zinc as Zinc Picolinate Chloride (10mg, 91% DV) — Zinc picolinate in a highly bioavailable form at 91% DV. Zinc is required for normal thyroid hormone receptor function (thyroid hormone receptors are zinc finger transcription factors), normal TSH production, and normal T4 to T3 conversion via 5'-deiodinase.*

Manganese as Manganese Citrate Carbonate (2mg, 87% DV) — Supporting normal Mn-SOD antioxidant protection of thyroid tissue — essential because the thyroid generates hydrogen peroxide as a normal byproduct of thyroid hormone synthesis.*

Potassium as Potassium Aspartate Chloride Carbonate (40mg, <1% DV) — Supporting normal electrolyte balance and healthy cellular membrane potential.*

Guggul Gum Extract 10% Guggulsterones (Commiphora mukul, 250mg per serving) — Standardised to 10% guggulsterones — providing 25mg of active guggulsterones per serving. Guggul (Commiphora mukul) is an Ayurvedic resin used for centuries in Indian traditional medicine for thyroid and metabolic support. Guggulsterones are the primary bioactive steroids of guggul — specifically studied for their activity on thyroid function.*

Guggulsterones are ligands for bile acid receptors (FXR and TGR5) and have been studied for their influence on the enzyme iodothyronine 5'-deiodinase — which catalyses the peripheral conversion of T4 (storage thyroid hormone) to T3 (active thyroid hormone). Normal T4 to T3 conversion is one of the most clinically relevant aspects of thyroid function and a primary mechanism through which thyroid hormone sufficiency is maintained. Guggul's inclusion as the primary botanical in Thyroid Support — at 250mg standardised to 10% guggulsterones — reflects its specific relevance to the peripheral thyroid hormone activation pathway.*

L-Tyrosine (250mg per serving) — The essential amino acid building block for thyroid hormone synthesis. Both T4 and T3 are constructed from two tyrosine residues within thyroglobulin, iodinated by thyroid peroxidase (which also requires riboflavin 5 sodium phosphate — also in this formula). Without adequate L-Tyrosine, thyroid hormone synthesis is impaired regardless of iodine availability. At 250mg, L-Tyrosine provides a meaningful thyroid hormone precursor amino acid dose.*

L-Aspartic Acid (200mg per serving) — Supporting normal mitochondrial energy metabolism via the malate-aspartate shuttle, normal pituitary function, and normal TSH (thyroid-stimulating hormone) production — the pituitary signal that drives thyroid hormone synthesis.*

Thyroid Support™ vs Thyroid Plus™ — which is right for whom?

Both Thyroid Support™ and Thyroid Plus™ provide the same B vitamin foundation (B1, B2, Niacin), the same mineral profile (Zinc, Magnesium, Manganese, Potassium), L-Tyrosine, and L-Aspartic Acid. The key differences are:

Thyroid Support™ is fully vegetarian, contains Iodine 450mcg (a critical differentiator — iodine is the element directly incorporated into thyroid hormones), uses active Riboflavin 5 Sodium Phosphate B2, and uses Guggul 10% guggulsterones as the thyroid-specific botanical for T4 to T3 conversion support. No glandular ingredients.*

Thyroid Plus™ includes Thyroid glandular 130mg and uses standard riboflavin — appropriate for individuals who want direct thyroid tissue-specific factors alongside nutritional support but do not require iodine supplementation or prefer the glandular approach.*

At a glance — what this formula supports

• Normal thyroid hormone synthesis via Iodine 450mcg & L-Tyrosine 250mg*
• Normal T4 to T3 peripheral conversion via Guggul 10% guggulsterones & Zinc deiodinase support*
• Normal thyroid peroxidase (TPO) activity via active Riboflavin 5 Sodium Phosphate*
• Normal pituitary TSH regulation via L-Aspartic Acid*
• Normal thyroid hormone receptor function via Zinc 91% DV*
• Comprehensive vegetarian, glandular-free thyroid nutritional support*

Quality you can verify

Every batch of Thyroid Support™ is manufactured in a GMP-certified facility, 100% vegetarian, non-GMO, and third-party tested for purity and potency. No glandular ingredients — fully vegetarian.

60 vegetarian capsules per bottle (30 servings).

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Warnings

WARNING: If you are pregnant or breastfeeding, consult your physician before using this product — contains 450mcg iodine per serving. If you have a thyroid condition, are taking thyroid medications, or have iodine sensitivity, consult your healthcare provider before use. If you are taking blood thinners or any medications, consult your healthcare provider before use — Guggul may interact with certain medications.