🌸Korean Traditional Medicine

Cinnamon Bark (Gyepi)

Cinnamomum cassia

About Cinnamon Bark (Gyepi)

Cinnamon Bark (Gyepi) (Cinnamomum cassia) is a herb used in the Korean Traditional Medicine tradition to help with Circulation, Pain, Diabetes, and Cold Extremities. The bark is the part traditionally used, taken internally.

Botanical background

Cinnamomum cassia, called Chinese cassia or Chinese cinnamon, is an evergreen tree originating in southern China and widely cultivated there and elsewhere in South and Southeast Asia. It is one of several species of Cinnamomum used primarily for its aromatic bark, which is used as a spice. The buds are also used as a spice, especially in India, and were used by the ancient Romans.

Source: Wikipedia, via iNaturalist

Parts used

Bark · internal
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Decoction

1–2 cups daily
  • Add 1–2 tsp of dried Cinnamon Bark (Gyepi) to 2 cups of cold water.
  • Bring to a boil, then simmer for 15–20 minutes.
  • Strain and drink warm.
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Tincture

20–40 drops in water, 2–3× daily
  • Pack dried Cinnamon Bark (Gyepi) into a jar and cover with 40–60% alcohol.
  • Seal and steep for 4–6 weeks, shaking daily.
  • Strain and store in a dark dropper bottle.
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Powder / Capsule

500 mg – 1 g, 1–3× daily
  • Grind dried Cinnamon Bark (Gyepi) into a fine powder.
  • Fill size 00 capsules or stir into smoothies or honey.

Pregnancy, Breastfeeding & Children

No herb-specific pregnancy/child safety research is documented for Cinnamon Bark (Gyepi) in our references — the guidance below is based on its general effect category, not research on Cinnamon Bark (Gyepi) itself. Always confirm with a midwife, doctor, or pediatrician.

Pregnancy

Use Caution

This herb may affect blood sugar levels. Given the importance of stable glucose control in pregnancy, herbs in this category are generally used only under medical guidance, particularly alongside any gestational diabetes monitoring — this is a general, mechanism-based caution, not herb-specific research.

Breastfeeding

Use Caution

Generally used cautiously during breastfeeding, particularly if managing blood sugar medically.

Children

Use Caution

Children are more sensitive to blood-sugar swings given their smaller body size — these herbs are generally used cautiously and under guidance.

Contraindications

  • Pre-surgery — discontinue at least 2 weeks prior (potential antiplatelet effect)
  • Diabetes medications — may enhance hypoglycaemic effect; monitor blood glucose closely

Warnings

⛔ Diabetes Medications

May enhance the blood sugar–lowering effect of insulin or oral diabetes medications. Monitor blood glucose closely.

⛔ Heart & Blood Pressure Medications

May interact with antihypertensive drugs, blood thinners, or cardiac medications. Do not combine without medical guidance.

⚠️ Allergic Reactions

Discontinue immediately if you experience rash, itching, swelling, or difficulty breathing.

⚠️ Not Medical Advice

This information is for educational purposes only. Always consult a qualified healthcare provider before using herbal remedies.

Drug & herb interactions

May thin the blood

Watch for: Anticoagulants (warfarin), antiplatelets (aspirin, clopidogrel), and other blood-thinning herbs or supplements (ginkgo, garlic, fish oil, vitamin E)

Combining blood-thinning substances can increase bleeding risk, including before surgery or dental work.

May affect blood sugar

Watch for: Insulin and oral diabetes medications (metformin, sulfonylureas)

Additive blood-sugar-lowering effects can risk hypoglycemia — monitor glucose closely.

Where to find in nature

Native region

Korea, China, Japan

Climate

Temperate

Habitat

Mountain forests, hillside farmland, and traditional herb gardens of the Korean peninsula

🌿 To see Cinnamon Bark (Gyepi) growing, visit botanical gardens, university plant collections, or specialist herb nurseries near you. If foraging in the wild, always work with an expert identifier — never consume a plant you are not 100% certain of.

Where to buy

In store

  • Health food stores (Whole Foods, Natural Grocers, Holland & Barrett, GNC)
  • Naturopathic clinics and integrative medicine practices
  • Specialist herbal apothecaries and herbalist practices
  • Farmers markets with herb vendors

Online

iHerb

Wide selection of standardised extracts, capsules, and powders with lab testing

Mountain Rose Herbs

Premium bulk dried herbs — certified organic, ethically sourced

Starwest Botanicals

Large selection of certified organic bulk herbs and powders

Herb Pharm

High-quality liquid extracts and tinctures, rigorous quality standards

Amazon

Convenient — verify brand certifications and check third-party testing

Etsy

Small-batch artisan herbalists, hand-harvested and wildcrafted herbs

Quality tips

When buying Cinnamon Bark (Gyepi), look for: certified organic labelling, clearly stated country of origin, third-party lab testing for heavy metals and pesticides, and a batch expiry date. Standardised extracts offer consistent dosing; bulk dried herbs are more economical for regular use. Avoid very cheap, unlabelled products — quality varies enormously.