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Supplements/Amino Acid

L-Tyrosine (Thyroid Substrate)

Amino acid substrate paired with iodine to form thyroid hormones.

Thyroid SupportEnergy ProductionCognitive Performance

Overview

Amino acid substrate paired with iodine to form thyroid hormones.

Natural sources
    Common forms

      Mechanism of action

      Tyrosine + iodine → MIT/DIT → T4/T3.

      Pathways

        Effects on the body

        Organ system effects

        Evidence-based benefits

        Cognitive support under stress

        Moderate evidence

        Potential side effects

        Common
          Rare
            Serious

              Drug interactions

              MAOIs
              Hypertensive crisis risk.
              severe

              Supplement interactions

              Pairs well with

              None listed.

              Avoid combining with

              No specific avoidances listed.

              Dosing & bioavailability

              Typical dose
              500–1500 mg AM
              With food?
              Empty stomach

              Where to buy

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              Thorne
              Practitioner-grade · NSF tested

              Scientific evidence (8)

              Systematic reviewJ Psychiatr Res · 2015

              L-tyrosine, thyroid hormone synthesis, and stress performance

              Jongkees BJ, et al.

              Review of tyrosine on cognition and thyroid substrate.

              Key findings

              Precursor for T3/T4; performance benefits under stress.

              Open study
              Systematic reviewPubMed (NLM) · 1970

              PubMed: L-Tyrosine (Thyroid Substrate) — Cognitive support under stress

              Live PubMed search

              Live results for "L-Tyrosine (Thyroid Substrate) Cognitive support under stress" across the PubMed/MEDLINE peer-reviewed index.

              Key findings

              Opens current human and preclinical literature matching L-Tyrosine (Thyroid Substrate) and "Cognitive support under stress". Filter by RCT, meta-analysis, or year on the results page.

              Open study
              Systematic reviewPubMed (NLM) · 1970

              PubMed: L-Tyrosine (Thyroid Substrate) — randomized controlled trial

              Live PubMed search

              Live results for "L-Tyrosine (Thyroid Substrate) randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

              Key findings

              Opens current human and preclinical literature matching L-Tyrosine (Thyroid Substrate) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

              Open study
              Systematic reviewPubMed (NLM) · 1970

              PubMed: L-Tyrosine (Thyroid Substrate) — meta-analysis

              Live PubMed search

              Live results for "L-Tyrosine (Thyroid Substrate) meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

              Key findings

              Opens current human and preclinical literature matching L-Tyrosine (Thyroid Substrate) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

              Open study
              Systematic reviewPubMed (NLM) · 1970

              PubMed: L-Tyrosine (Thyroid Substrate) — pharmacokinetics

              Live PubMed search

              Live results for "L-Tyrosine (Thyroid Substrate) pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

              Key findings

              Opens current human and preclinical literature matching L-Tyrosine (Thyroid Substrate) and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

              Open study
              Systematic reviewPubMed (NLM) · 1970

              PubMed: L-Tyrosine (Thyroid Substrate) — safety adverse events

              Live PubMed search

              Live results for "L-Tyrosine (Thyroid Substrate) safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

              Key findings

              Opens current human and preclinical literature matching L-Tyrosine (Thyroid Substrate) and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

              Open study
              Systematic reviewPubMed (NLM) · 1970

              PubMed: L-Tyrosine (Thyroid Substrate) — dose response

              Live PubMed search

              Live results for "L-Tyrosine (Thyroid Substrate) dose response" across the PubMed/MEDLINE peer-reviewed index.

              Key findings

              Opens current human and preclinical literature matching L-Tyrosine (Thyroid Substrate) and "dose response". Filter by RCT, meta-analysis, or year on the results page.

              Open study
              Systematic reviewGoogle Scholar · 1970

              Google Scholar: L-Tyrosine (Thyroid Substrate) — clinical evidence

              Live Scholar search

              Cross-database citation index for L-Tyrosine (Thyroid Substrate) as it relates to "clinical evidence".

              Key findings

              Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

              Open study
              Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.