Energy & blood sugar · Digestion · Metabolic support
Ceylon cinnamon: grandma's "true" cinnamon and your blood sugar
Why the type of cinnamon matters, what the metabolic research really shows for Cinnamomum verum, and how much is safe every day.
By Mariana Farias, Founder & Editor of Las Recetas de mi Abuela · Updated November 4, 2026
Fact-checked against USDA FoodData Central, the NIH National Center for Complementary and Integrative Health (NCCIH), the European Food Safety Authority (EFSA) and peer-reviewed studies in PubMed. Educational content — not medical advice.
Key takeaways
- There are two main kinds of cinnamon. Ceylon ("true" cinnamon) has only traces of coumarin; cassia can have hundreds of times more.
- Coumarin in large amounts can harm the liver. With cassia, about 1 teaspoon a day can reach the safety limit for a small adult.
- Research on cinnamon and blood sugar is mixed: some modest benefits, many inconsistent results.
- Cinnamon never replaces diabetes medication, and may add to its effect.
In Mexican kitchens, cinnamon is not a dessert spice: it is the soul of café de olla, atole, arroz con leche, Christmas ponche and the simple té de canela that grandma served when someone had a stomachache or a cold evening. Without knowing it, she was usually using the safest kind: the soft, layered Ceylon cinnamon that Mexico imports in huge quantities from Sri Lanka.
What is Ceylon cinnamon?
Cinnamon is the dried inner bark of trees in the genus Cinnamomum, of the laurel family (Lauraceae). Ceylon cinnamon, Cinnamomum verum (also called C. zeylanicum), is native to Sri Lanka and southern India. Workers peel thin strips of inner bark from young shoots and roll them by hand, nesting many layers into one fragile, cigar-like quill.
Cassia (Cinnamomum cassia and related species from China, Indonesia and Vietnam) is cheaper and is the most common ground cinnamon in U.S. supermarkets. Here is how to tell them apart:
- Ceylon: light tan, many thin papery layers, crumbles between your fingers, delicate and sweet aroma.
- Cassia: dark reddish-brown, one thick hard layer rolled inward, very hard to break, strong and spicy aroma.
Active compounds
- CinnamaldehydeThe main compound of the bark oil and the source of cinnamon's flavor. Studied for antioxidant, antimicrobial and glucose-related effects.
- EugenolPresent in smaller amounts in the bark and abundant in the leaf oil — the same compound that defines clove.
- Procyanidins (polyphenols)Type-A procyanidins and other polyphenols that give cinnamon a high antioxidant capacity in lab tests.
- CoumarinA natural compound that is toxic to the liver in high doses. Only traces in Ceylon; much higher in cassia.
What science says about cinnamon
1. Blood sugar and metabolic support Mixed evidence
This is the most studied use of cinnamon. Several meta-analyses of clinical trials found that cinnamon supplements produced small reductions in fasting blood sugar in people with type 2 diabetes or prediabetes. However, the trials vary a lot in dose, duration and type of cinnamon, and many found no effect on HbA1c, the long-term marker doctors rely on. The NIH's National Center for Complementary and Integrative Health concludes that studies do not clearly support using cinnamon for any health condition. Also important: most of these studies used cassia, not Ceylon.
In practical terms, cinnamon is a smart way to add flavor without sugar — a cinnamon stick in your coffee instead of two spoonfuls of sugar is a real metabolic win. But it is not a treatment.
2. Antioxidant activity Lab evidence
Cinnamon ranks among the spices with the highest polyphenol content. In the lab, its extracts neutralize free radicals and reduce markers of oxidation. Whether normal food amounts produce a meaningful antioxidant effect in the body is still not clear.
3. Digestion Traditional use
Cinnamon tea is a classic Latin American remedy for gas, cramps and an upset stomach. Traditional systems such as Ayurveda also use it as a "warming" digestive. Human evidence is limited, but a warm, unsweetened cinnamon tea is a gentle, low-risk choice after meals.
4. Cholesterol and blood pressure Inconsistent evidence
Some reviews report small improvements in triglycerides, LDL cholesterol or blood pressure with cinnamon supplements; others find no effect. The results are too inconsistent to recommend cinnamon for heart health.
5. The coumarin issue Well established
The European Food Safety Authority set a tolerable daily intake of 0.1 mg of coumarin per kg of body weight. Cassia often contains several thousand milligrams of coumarin per kilogram, so for a 60 kg adult, as little as one teaspoon of cassia a day can reach that limit. Ceylon contains only traces. If you use cinnamon every day — in tea, oatmeal or supplements — choosing Ceylon is the single most important safety decision.
Botanical and nutrition facts
| Scientific name | Cinnamomum verum J. Presl (syn. C. zeylanicum) |
|---|---|
| Family | Lauraceae (laurel family) |
| Part used | Dried inner bark; essential oil from bark and leaves |
| Origin | Sri Lanka and southern India |
| Main compound | Cinnamaldehyde (bark oil); eugenol (leaf oil) |
| Coumarin | Traces in Ceylon; much higher in cassia |
| Flavor | Sweet, warm, delicate, slightly citrusy |
| Nutrient | Per 100 g | Per 1 tsp (2.6 g) |
|---|---|---|
| Energy | 247 kcal | 6 kcal |
| Carbohydrates | 80.6 g | 2.1 g |
| Dietary fiber | 53.1 g | 1.4 g |
| Protein | 4.0 g | 0.1 g |
| Fat | 1.2 g | 0.03 g |
| Manganese | 17.5 mg | 0.45 mg (≈20% DV) |
| Calcium | 1,002 mg | 26 mg |
| Iron | 8.3 mg | 0.22 mg |
| Potassium | 431 mg | 11 mg |
| Vitamin K | 31.2 µg | 0.8 µg |
Source: USDA FoodData Central (SR Legacy, "Spices, cinnamon, ground"; the USDA entry does not specify the species). DV = Daily Value for adults (manganese 2.3 mg). Values are rounded.
Dosage calculator
How much cinnamon should I use?
Choose a preparation and how many servings you want. The quantities adjust automatically.
👵 Grandma's té de canela
- Put 1 Ceylon cinnamon stick (5–7 cm) in a small pot with 300 ml of water — a little will evaporate.
- Bring to a boil, lower the heat, cover and simmer for 10 minutes until the water turns amber.
- Turn off the heat and let it rest 5 minutes. Strain.
- Drink it plain or with a few drops of lemon. If you need sweetness, use a little honey or piloncillo instead of white sugar.
Precautions and contraindications
🟢 Generally safe
- Ceylon cinnamon in food and drinks, about 1 teaspoon (2–3 g) or 1–2 sticks a day for healthy adults.
- Children in normal food amounts (atole, arroz con leche).
🟡 Ask your doctor first
- Diabetes medication or insulin: cinnamon may add to the glucose-lowering effect. Monitor your levels.
- Pregnancy and breastfeeding: food amounts are fine; avoid supplements and oil.
- Planned surgery: stop cinnamon supplements about 2 weeks before.
- Mouth sores or allergy: cinnamaldehyde (also in cinnamon gum and candy) can cause mouth irritation and allergic reactions.
🔴 Avoid
- Liver disease, or taking medications that can affect the liver: avoid cassia and cinnamon supplements.
- Large daily amounts of cassia (more than about 1 teaspoon), especially in children and small adults.
- Cinnamon essential oil by mouth or on the skin: it can burn and sensitize.
- The "cinnamon challenge": swallowing or inhaling dry ground cinnamon can cause choking and lung damage.
Frequently asked questions
What is the difference between Ceylon cinnamon and cassia?
Ceylon cinnamon (Cinnamomum verum) has thin, papery layers that crumble easily and a mild, sweet flavor. Cassia is a single thick, hard layer with a stronger taste. The key health difference is coumarin: cassia can contain hundreds of times more coumarin than Ceylon.
Does cinnamon lower blood sugar?
Some studies and meta-analyses found modest reductions in fasting blood sugar in people with type 2 diabetes, but results are inconsistent and most studies used cassia. According to the NIH, the evidence does not clearly support cinnamon for any health condition. It should never replace diabetes medication.
How much cinnamon is safe per day?
The European Food Safety Authority set a tolerable daily intake for coumarin of 0.1 mg per kg of body weight. With cassia, about one teaspoon a day can reach that limit for a small adult. Ceylon cinnamon has only traces of coumarin, so about 1 teaspoon (2–3 g) a day is a comfortable culinary amount.
Is the cinnamon sold in Mexico Ceylon cinnamon?
Very often, yes. Mexico is one of the largest importers of Ceylon cinnamon from Sri Lanka, and the soft, layered sticks used for café de olla and atole are usually Ceylon. Ground cinnamon sold in the United States is more often cassia.
Can I take cinnamon if I am pregnant?
Cinnamon in normal food amounts is generally considered fine during pregnancy. Cinnamon supplements, capsules and essential oil are not recommended unless your doctor approves them.
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Perfect pairing
Cinnamon + hibiscus
Agua de jamaica with a Ceylon cinnamon stick is a Mexican classic. Hibiscus has some of the best evidence of any kitchen drink for lowering blood pressure — find out how much to drink and how to avoid the sugar trap.
Read the hibiscus guide →Keep reading
More ingredients from grandma's kitchen
CloveSyzygium aromaticum
LemonCitrus limon
ChamomileMatricaria chamomilla
GingerZingiber officinale
TurmericCurcuma longa
GarlicAllium sativum
OreganoOriganum vulgare
RosemarySalvia rosmarinus
Bay leafLaurus nobilis
PeppermintMentha × piperita
HibiscusHibiscus sabdariffa
Aloe veraAloe barbadensis
Chia seedsSalvia hispanica
Star aniseIllicium verum
ValerianValeriana officinalis
Apple cider vinegarMalus domestica
FlaxseedLinum usitatissimum
EucalyptusEucalyptus globulus
Raw honeyApis mellifera
Sources
- U.S. Department of Agriculture. FoodData Central — Spices, cinnamon, ground. fdc.nal.usda.gov
- NIH National Center for Complementary and Integrative Health (NCCIH). Cinnamon. nccih.nih.gov
- European Food Safety Authority (2008). Coumarin in flavourings and other food ingredients with flavouring properties. EFSA Journal 793.
- PubMed — meta-analyses of cinnamon and glycemic control. pubmed.ncbi.nlm.nih.gov
- PubMed — coumarin content of Ceylon and cassia cinnamon. pubmed.ncbi.nlm.nih.gov
- PubMed — cinnamaldehyde contact allergy and stomatitis. pubmed.ncbi.nlm.nih.gov
⚕️ This guide is for educational purposes and does not replace the advice of a doctor or pharmacist. If you have diabetes, never change your medication on your own. Read our full medical disclaimer.