Thyroid hormone

Levothyroxine

Also known as: Synthroid, Euthyrox

Best time

On waking, empty stomach — or bedtime

05:30–07:30· 30–60 min before breakfast
22:00–23:30· Bedtime, ≥3 h after last meal

Absorption is best on an empty stomach: either before breakfast or at bedtime long after dinner.

Strong evidence

Consistent clinical trials or official prescribing guidance support this timing.

Why this time works

Food, coffee, calcium and iron all reduce levothyroxine absorption. Morning dosing 30–60 minutes before breakfast is standard; trials show bedtime dosing (3+ hours after the last meal) works at least as well and may raise thyroid levels slightly.

Body rhythm involved

Gastric emptying and gut pH change across the day; TSH naturally peaks at night.

Other hormones & diabetes medicines

Prednisolone / prednisone

Deltasone, Pred Forte (oral forms)

Morning

Hormones & diabetesStrong evidence

Hydrocortisone (replacement)

Cortef, Plenadren

Largest dose on waking, smaller early afternoon

Hormones & diabetesStrong evidence

Metformin

Glucophage, Glucophage XR

With meals (XR with the evening meal)

Hormones & diabetesStrong evidence