Calcitonin is a hormone that plays a key role in keeping your bones strong and your calcium levels balanced. It is produced naturally in your body and can also be used as a medical treatment for certain bone and calcium disorders. In this article, we explain what calcitonin is, how it works, what conditions it treats, and what side effects to watch for. As always, speak with your family doctor or visit a walk-in clinic before starting any new treatment.
What Is Calcitonin?
Calcitonin is a hormone produced mainly by the thyroid gland, but also by the parathyroid glands and the thymus. Its primary job is to regulate calcium in your blood. When calcium levels rise too high, calcitonin steps in to bring them back down.
Think of calcitonin as a traffic controller for calcium. It directs calcium out of the bloodstream and into your bones, where it is needed most. This process helps keep your skeleton strong and your blood chemistry in safe balance.
You may also see calcitonin referred to by its older name, thyrocalcitonin. Both terms mean the same thing. Modern medical literature uses calcitonin more often.
How Does Calcitonin Work in the Body?
Calcitonin works in three main ways to control calcium levels. First, it encourages calcium to move from the blood into bone tissue. Second, it slows the amount of calcium your intestines absorb from food. Third, it helps your kidneys flush out extra calcium through urine.
Together, these actions lower the level of calcium circulating in your blood. This is especially important when calcium levels become abnormally high, a condition called hypercalcaemia. Left untreated, high blood calcium can cause fatigue, kidney problems, and heart irregularities.
Your body releases calcitonin automatically when it senses that blood calcium is too high. This makes it part of a natural feedback system — one of many built-in checks your body uses to stay healthy. Learn more about hypercalcaemia and its causes at Mayo Clinic.
The Connection Between Calcitonin and Bone Density
Bones are not static. They are living tissue that constantly breaks down and rebuilds. Specialised cells called osteoclasts break down old bone, while osteoblasts build new bone. Calcitonin slows the activity of osteoclasts, which helps preserve bone density.
This is why calcitonin is useful in treating conditions that weaken bones. By slowing bone breakdown, it gives the body more time to build new, stronger bone tissue. This is especially helpful in older adults, who naturally lose bone density over time.
Where Does Medical Calcitonin Come From?
When used as a medication, calcitonin comes from two main sources. It can be extracted from animals — most commonly salmon or pigs — or it can be made synthetically in a laboratory. Synthetic calcitonin is designed to closely mimic the natural human hormone.
Interestingly, salmon calcitonin is actually more potent than human calcitonin. This means a smaller dose can produce a stronger effect. For this reason, salmon-derived calcitonin has been widely used in clinical settings for decades.
Synthetic versions are also available and have become more common. They are generally well tolerated and produce consistent results. Your doctor or specialist will recommend the most appropriate form based on your health needs and medical history.
Medical Uses of Calcitonin
Calcitonin therapy is used to treat several serious bone and calcium conditions. It is not a first-line treatment for most people, but it can be highly effective in specific situations. Here are the main conditions where calcitonin may be prescribed.
Osteoporosis
Osteoporosis is a condition where bones become thin and fragile, increasing the risk of fractures. It is very common in Canada, particularly among women after menopause. Calcitonin helps slow bone loss and can reduce pain associated with spinal fractures caused by osteoporosis.
However, it is important to note that calcitonin is generally considered a secondary option for osteoporosis. Other medications, along with adequate calcium and vitamin D intake, are usually tried first. Health Canada maintains a database of approved drug products, including those used for bone conditions like osteoporosis.
Paget’s Disease of Bone
Paget’s disease is a chronic condition that disrupts the normal cycle of bone renewal. Affected bones become enlarged, misshapen, and weaker than normal. Calcitonin can help slow this abnormal bone remodelling process and reduce symptoms such as bone pain.
Treatment with calcitonin can bring significant relief to people living with Paget’s disease. It does not cure the condition, but it can meaningfully improve quality of life. Your specialist will monitor your response to treatment over time.
Algodystrophy (Complex Regional Pain Syndrome)
Algodystrophy, also known as complex regional pain syndrome (CRPS), is a painful condition that usually affects a limb after an injury or surgery. It causes intense, burning pain, swelling, and changes in skin colour and temperature. Calcitonin has been used to help manage the bone-related pain associated with this condition.
The exact reason calcitonin helps with CRPS is not fully understood. However, its ability to reduce bone turnover and its potential pain-relieving properties may both play a role. It is typically used as part of a broader pain management plan.
Hypercalcaemia
Hypercalcaemia means having too much calcium in your blood. It can result from overactive parathyroid glands, certain cancers, or excessive vitamin D intake. High calcium levels can cause nausea, confusion, and in severe cases, kidney failure.
Calcitonin acts quickly to lower blood calcium levels, which is why it is sometimes used in urgent or emergency situations. It works faster than many other treatments for hypercalcaemia. However, its effect can wear off over time, so it is often combined with other therapies for longer-term management.
How Is Calcitonin Given?
Calcitonin is most commonly given by injection. The injection is usually intramuscular, meaning it goes into the muscle. In some cases, it may be given subcutaneously, which means just under the skin.
A nasal spray form of calcitonin has also been used, particularly for osteoporosis. However, availability and approval can vary by country and province. Your pharmacist or doctor can tell you which forms are currently available in your area under your provincial health plan.
The dose and frequency of calcitonin treatment depend on the condition being treated and how your body responds. Never adjust your dose on your own. Always follow the guidance of your healthcare provider.
Side Effects of Calcitonin
Like all medications, calcitonin can cause side effects. Most are mild and manageable, but it is important to know what to watch for. Reporting any unusual symptoms to your doctor promptly is always a good idea.
Common Side Effects
The most frequently reported side effects of calcitonin include:
Nausea and vomiting — these digestive symptoms are among the most common reactions
Diarrhoea — loose stools may occur, especially early in treatment
Abdominal pain — some people experience cramping or stomach discomfort
Facial flushing — a sudden redness or warmth in the face, neck, or chest, sometimes called a vasomotor flush
Injection site reactions — redness, swelling, or tenderness where the injection was given
These effects often improve as your body adjusts to the medication. Taking calcitonin at bedtime can sometimes help reduce nausea. Talk to your doctor or pharmacist if side effects are bothering you.
Allergic Reactions
Allergic reactions to calcitonin are possible, though not common. Symptoms of an allergic reaction can include skin rash, itching, difficulty breathing, or swelling of the face and throat. A severe allergic reaction — called anaphylaxis — is a medical emergency.
If you experience any signs of a serious allergic reaction, call 911 or go to your nearest emergency department immediately. Before starting calcitonin, your doctor may perform a skin test to check for sensitivity, particularly with animal-derived forms of the hormone.
Long-Term Considerations
Some research has raised questions about a possible link between long-term calcitonin use and a slightly increased risk of certain cancers. As a result, regulatory agencies in Canada and elsewhere have reviewed its use carefully. Healthline provides a helpful overview of calcitonin’s uses and safety profile.
For most people, the benefits of calcitonin therapy outweigh the risks when used appropriately and monitored by a doctor. Your healthcare provider will weigh all factors before recommending this treatment. Regular follow-up appointments are an important part of safe long-term use.
When to See a Doctor
You should speak with your family doctor if you have been diagnosed with osteoporosis, Paget’s disease, or hypercalcaemia and want to know whether calcitonin therapy is right for you. Your doctor can review your full health history and recommend the most suitable treatment plan.
If you do not have a family doctor, a walk-in clinic can be a helpful first step. Staff there can assess your symptoms and refer you to a specialist if needed. Many provinces also have nurse practitioners who can discuss bone health and treatment options with you.
Seek urgent medical care if you develop signs of very high blood calcium — such as extreme fatigue, confusion, increased thirst, or frequent urination. These symptoms can come on quickly and require prompt attention. Do not wait for a scheduled appointment if you feel seriously unwell.
You should also contact your doctor right away if you experience signs of an allergic reaction to calcitonin or if your side effects are severe and not improving. Adjusting or changing your treatment is always possible with your doctor’s guidance.
Frequently Asked Questions About Calcitonin
What does calcitonin do in the body?
Calcitonin is a hormone that lowers blood calcium levels by moving calcium from the blood into bones, reducing calcium absorption in the intestines, and increasing calcium excretion through the kidneys. It helps protect bone density and keeps calcium levels in a healthy range. This makes calcitonin essential for both bone strength and overall mineral balance.
What conditions is calcitonin used to treat?
Calcitonin is used medically to treat osteoporosis, Paget’s disease of bone, complex regional pain syndrome (algodystrophy), and hypercalcaemia (high blood calcium). It helps slow bone breakdown, reduce pain, and rapidly lower dangerously high calcium levels. Your doctor will determine whether calcitonin is the right treatment for your specific condition.
Is calcitonin safe to use long term?
Most people tolerate calcitonin well for short to medium-term use, but long-term use has raised some concerns about a potential slight increase in cancer risk. Health regulators in Canada and internationally continue to monitor this carefully. Always use calcitonin under the supervision of a doctor who can assess your individual risk and benefit.
What are the side effects of calcitonin?
Common side effects of calcitonin include nausea, vomiting, diarrhoea, abdominal pain, and facial flushing. Allergic reactions are less common but possible. Most side effects are mild and tend to improve as your body adjusts to the medication.
Does calcitonin help with osteoporosis?
Yes, calcitonin can help slow bone loss and reduce pain in people with osteoporosis, particularly pain from spinal fractures. However, it is usually considered a secondary treatment option after other medications, calcium, and vitamin D have been tried. Talk to your family doctor about whether calcitonin fits into your osteoporosis management plan.
How is calcitonin given as a medication?
Calcitonin medication is most commonly administered by intramuscular or subcutaneous injection, meaning it is injected into muscle or just under the skin. A nasal spray form has also been used for osteoporosis treatment. Your doctor or pharmacist will explain which form is appropriate for you and how to use it safely.
Key Takeaways
Calcitonin is a natural hormone produced mainly by the thyroid gland that regulates calcium levels in the blood and bones.
It works by moving calcium into bones, reducing intestinal absorption, and increasing kidney excretion of calcium.
Medical calcitonin is derived from animals (salmon or pigs) or produced synthetically to mimic the human hormone.
It is used to treat osteoporosis, Paget’s disease of bone, algodystrophy (CRPS), and hypercalcaemia.
Calcitonin is most often given by injection, though nasal spray forms have also been used.
Common side effects include nausea, flushing, and digestive upset; allergic reactions are possible but rare.
Long-term use should be monitored carefully by a healthcare provider due to potential risks.
Always speak with your family doctor or visit a walk-in clinic before starting or stopping any hormone therapy.
