Moderate interactionModerate

Sea moss and Levothyroxine: interaction, severity and spacing

Sea moss and Levothyroxine interact because sea moss is often very high in iodine; iodine load can alter thyroid function in both directions and destabilise replacement therapy. Take them with care. Moderate risk.

Last reviewed: 2026-09-20Reviewed by: StackingRight clinical review

The interaction in detail

Summary of the Sea moss and Levothyroxine interaction
PairSea moss and Levothyroxine
TypeNutrient–drug interaction
SeverityModerate
Required spacingNone specified
OnsetAt the time of dosing

Mechanism

Sea moss is often very high in iodine; iodine load can alter thyroid function in both directions and destabilise replacement therapy.

What to do

Check the iodine content before use and have thyroid labs monitored if you take levothyroxine.

How to fit both into one day

Levothyroxine
morningempty stomach

Levothyroxine needs an empty stomach and gastric acid for full absorption. Take it 30-60 minutes before breakfast with plain water, and keep calcium, iron and coffee at least 4 hours away.

Putting Sea moss in the morning and Levothyroxine in the morning satisfies the 0-hour separation without disrupting either one's absorption window.

Sea moss and Levothyroxine: common questions