What is cinnamon?

Cinnamon is the dried inner bark of a small evergreen tree. This page covers Cinnamomum verum, sold as Ceylon or "true" cinnamon. In the Caribbean it is called kannèl in Haiti and canela in Cuba and the Dominican Republic.

Most bark sold as cinnamon is a close cousin, cassia. Cassia is darker, harsher in taste, and much higher in a compound called coumarin. Large daily amounts of coumarin can harm the liver.

People use cinnamon three ways: as a kitchen spice, as a tea, and as a capsule. Supplement labels push it mainly for blood sugar.

Here is the honest verdict. As a spice, cinnamon is a food and is fine for most people. As a medicine, the human evidence is weak and mixed, and long use in tradition is not proof that it works or that it is safe.

How does cinnamon work?

No one has shown clearly how cinnamon acts in the human body.

In cell and animal studies, parts of cinnamon seem to help cells respond better to insulin. Insulin is the hormone that moves sugar out of your blood.

In test tubes, cinnamon extract also slows an enzyme that breaks starch down into sugar. If that happened in your gut, sugar would enter the blood more slowly after a meal. That step has not been proven in people.

In laboratory tests, cinnamon oil kills many bacteria and fungi. That does not mean it clears an infection inside the body or on your skin.

Cinnamon oil is also a known skin and mouth irritant. That part is well established, and it explains the warm, burning feel.

Human trials have mostly measured blood sugar and blood fats. The results do not agree with each other. So the lab story above stays a theory, not a proven path.

What forms does cinnamon come in?

Cinnamon is sold in these forms:

Sticks, also called quills, used in teas, stews and drinks.

Ground powder, the usual kitchen spice.

Tea bags and loose bark for brewing.

Capsules and tablets, often labelled as extract.

Tinctures, which are alcohol extracts.

Essential oil, which is very strong and meant for scent, not for swallowing.

Labels often do not say which species is inside. "Cinnamon" with no species name is usually cassia. If you want Ceylon, the label should say Cinnamomum verum or Ceylon.

Water-based forms, such as tea, carry little coumarin. Powder and capsules carry whatever the bark holds.

Where it comes from:

Cinnamon is not native to the Caribbean. Colonial trade brought the trees and the bark from Sri Lanka and Asia from the 1700s onward. It took root in island cooking, drinks and home remedies.

In Haitian homes, tè kannèl was brewed for chills, colds and an upset stomach. In Cuba and the Dominican Republic, té de canela was given for period cramps and for stomach gas.

It was also drunk after childbirth in several island traditions, and steeped in rum and in sorrel drinks at Christmas.

These were household customs passed down by families, not tested treatments. They say what people valued, not what the bark does.

What does cinnamon help with?

• blood sugar in type 2 diabetes: This is the most studied use, and the results still do not agree. Dozens of small trials have given cinnamon to adults with type 2 diabetes. Some show a small drop in fasting blood sugar. Others show no change at all. Trials used different species, doses and lengths, which makes them hard to pool. A major review found the evidence too weak to support cinnamon as a treatment. Diabetes groups do not recommend it in place of medicine. Treat it as unproven, and never as a swap for your prescription.
• high cholesterol and blood fats: The evidence here is weaker than for blood sugar. Some small trials report lower triglycerides, a type of blood fat. Others find no change in cholesterol. Studies are short and small, so the findings are not reliable. There is no good reason to use cinnamon for this.
• period cramps: Caribbean and other traditions used cinnamon tea for cramps. A few small trials in young women report less pain with cinnamon capsules. The studies are small and not well controlled. This is early and unproven. It is not a reason to delay care for severe or worsening period pain.
• upset stomach and gas: Tradition used cinnamon tea after heavy meals and for a sour stomach. Warm spiced drinks can feel soothing. There is almost no human trial evidence for cinnamon alone here. In some people cinnamon does the opposite and causes heartburn.
• colds and sore throat: Home remedies across the islands mixed cinnamon with ginger, lime or honey for colds. In laboratory tests, cinnamon oil slows many bacteria and viruses. Whether that happens in your throat has not been shown. No trial shows cinnamon shortens a cold. A warm drink may ease the feeling, which is not the same thing.
• flavour in food and drinks: This use needs no defence. Cinnamon is a food spice, used worldwide in sweet and savoury cooking. In Caribbean kitchens it goes into tea, porridge, stewed fruit, sorrel and spiced rum. Used this way, in normal cooking amounts, it is safe for most people.

Which foods are rich in cinnamon?

1. cinnamon sticks in tea, stews and sorrel drink
2. ground cinnamon in porridge, rice pudding and baked goods
3. spiced rum and mulled drinks
4. curry and spice blends
5. cinnamon-flavoured gum, sweets and toothpaste

Practical Tips:

Cinnamon is itself a food, so there is no need to seek it elsewhere.

Flavoured gum, sweets and toothpaste are the usual cause of mouth soreness and ulcers. Many of these use cinnamon oil or a lab-made flavour, not bark.

If your mouth burns or peels, stop the flavoured product and see if it clears.

What are the side effects of cinnamon?

• burning or soreness in the mouth
• mouth ulcers from cinnamon-flavoured gum, sweets or toothpaste
• heartburn or stomach upset
• skin rash on contact with the oil or powder
• allergic reaction in people sensitive to balsam of Peru
• low blood sugar when combined with diabetes medicines
• liver injury, rare, linked to high daily cassia intake
• coughing and lung harm if dry powder is inhaled

Good to know:

Most people who use cinnamon as a spice have no trouble at all.

Mouth and skin irritation are the common complaints, and they come from the oil and from strong flavoured products. They settle when you stop.

Liver injury is rare and reported mainly with heavy daily cassia use or supplements. It is serious, and it is the main reason to prefer Ceylon cinnamon for daily use.

Swallowing dry powder on a dare can block or scar the airways. That has caused hospital admissions in teenagers.

How much cinnamon should you take?

• Recommended daily: This is not advice for you. It is what the market and the research look like. Capsule labels commonly carry 500 mg to 1 g of bark powder or extract per capsule. Trials in diabetes have used roughly 1 g to 6 g a day. European food safety advice sets a daily coumarin limit of about 0.1 mg per kilo of body weight. A few grams of cassia powder a day can reach that limit. Ceylon cinnamon (Cinnamomum verum) has only traces, so it is the safer choice for daily use. Cooking amounts, a few shakes or one stick in a pot, are not a concern for most people. If you take diabetes medicine or have any liver problem, ask your doctor or pharmacist before using supplements.
• Best time of day: Timing does not matter much, because no clear effect is proven. Studies that aimed at after-meal blood sugar gave it with or just before meals. Tea is usually drunk in the evening in Caribbean homes, by habit rather than design.
• With or without food: Taking cinnamon with food is the usual approach. Food lowers the chance of heartburn or a burning feeling in the stomach. Capsules on an empty stomach are more likely to irritate. As a spice, it is already part of a meal.
• Time to effect: Be ready for nothing to happen. In trials that did show a blood sugar change, it took several weeks. Taste and warmth are immediate; that is the spice, not a treatment. If you are tracking blood sugar, do not read one good day as proof.
• How long to take it: As a food spice, cinnamon is used year-round with no set limit. Supplement trials usually ran 6 to 16 weeks. Longer use has not been well studied. If you take capsules daily for months, have a reason and a review date. Daily high-dose cassia over long periods is the pattern linked to liver harm.