Minerals Thyroid gland

Calcitonin

Written by the VitaWhat editorial team · Medically reviewed by Steve Davis · Last reviewed 19 July 2026 · Editorial policy

Lowers blood calcium — the counterpart to parathyroid hormone.

What it does

Lowers blood calcium by slowing its release from bone

Too much

Raised calcitonin can be a marker of a rare thyroid cancer

Too little

Deficiency has little effect in humans (a minor role)

Keeping it balanced: Mainly of interest as a tumour marker and occasional medicine.

Sources & references

Think a hormone may be out of balance?

The symptoms of hormonal excess and deficiency are non-specific — tiredness, weight change, low mood and poor sleep have many everyday causes. No hormone problem can be self-diagnosed from a symptom list.

Diagnosis needs blood tests interpreted alongside your history, sometimes repeated at set times of day because many hormones vary hour to hour. Speak to a GP if symptoms are persistent; seek urgent care for severe symptoms such as confusion, fainting, chest pain or extreme thirst with frequent urination.

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