Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant
You should also be sure to tell your healthcare provider about all of the medicines you take, including prescription and nonprescription medications, vitamins, and herbal supplements.
Specific Tyrosine Warnings and Precautions
Warnings and precautions to be aware of concerning the safety of tyrosine include the following:
- Tyrosine is used by the body to make thyroid hormones. Therefore, if you have high thyroid hormone levels (such as with hyperthyroidism or Graves' disease), you should not take tyrosine supplements without your healthcare provider's approval and supervision. Tyrosine could make these conditions worse.
- Tyrosine supplements can interact with some medications (see Tyrosine Drug Interactions).
- If you have phenylketonuria (PKU), do not take tyrosine supplements unless your healthcare provider specifically recommends that you do so. It is important for people with PKU to closely monitor and balance their intake of amino acids, including tyrosine.
- If you decide to use supplements such as tyrosine, what you see on the label may not reflect what is in the bottle. For example, some herbal supplements have been found to be contaminated with heavy metals or prescription drugs, and some have been found to have much more or much less of the featured ingredient than their label states. Make sure the manufacturer of your tyrosine supplement is trusted and reputable. It is a good sign if a manufacturer abides by the rules of Good Manufacturing Practices (GMP) for drugs.
It is also a good sign if a product has the United States Pharmacopoeia (USP) seal, which means that the product has been independently tested and shown to contain the correct ingredients in the amounts listed on the label. Your pharmacist is a good resource for information about which manufacturers are most reputable.