The 7 Benefits of Calendula: Dosage & Safety

Calendula is a highly-revered herb that has gained popularity over centuries of use.  

Traditionally, calendula was used to support skin conditions, promote wound healing, release tension in the body, and prevent infections. 

As an edible herb, calendula flowers and leaves are often used in various cuisines (especially salads) due to their bitter properties. 

This article will look at the health benefits of calendula, its safety, and its history. 

What is Calendula?

Calendula is a sunny, annual garden herb in the Asteraceae (daisy) family. It’s a self-seeding plant in most climates and is an extremely hardy herb.

The scientific name for calendula is Calendula officinalis. Although its common name is “pot marigold,” it should not be confused with garden marigold (Tagetes spp.) as this species is not medicinal. 

The flower blossoms and leaves have been used in ancient medicine systems for millennia. In traditional medicine, the aerial parts are used as an oil or salve to heal wounds and as a tea to encourage digestion and reduce chronic ulcers. It is also distilled in water and used as an eye wash to reduce inflammation and soreness. 

Modern research shows that calendula’s anti-inflammatory, antimicrobial, and immunomodulating properties may be attributed to its various phytochemicals. These phytochemicals include flavonoids, triterpene saponins, and carotenoids. 

Numerous clinical and traditional accounts, along with animal and lab-based studies, highlight the wide range of calendula’s health benefits. 

Health Benefits of Calendula:

Below are the top research-backed studies and expert accounts from professional herbalists that summarize the benefits of calendula and its active constituents. 

1. May Reduce Inflammation

Like the herbs boswellia and yellow dock, Calendula is noted for its anti-inflammatory properties, although only a small amount of human studies have been conducted.

The body’s immune system triggers the inflammatory response when exposed to internal or external trauma. While short-term inflammation is a fundamental part of the healing process, chronic inflammation indicates a persistent issue and can cause long-term health issues.

A randomized comparative trial observing diaper dermatitis (a moderate skin rash) in infants discovered that calendula ointment was significantly more effective than aloe vera in reducing the rash symptoms. The infants received treatment three times per day for 10 days.   

Another clinical trial found that calendula and comfrey eliminated stomach ulcers and reduced painful symptoms in participants with duodenal ulcers. Researchers noted that the reduction in pain was correlated with reduced inflammation. 

In an animal study observing rats with skin wounds, researchers observed that calendula extract reduces inflammation during the healing process. The anti-inflammatory activity was attributed to the presence of triterpenes, especially taraxasterol and faradiol esters. 

Another animal study found that calendula extract reduced inflammation in rats with induced edemas. Researchers noted that this response might result from calendula’s ability to inhibit certain pro-inflammatory biomarkers. 

A recent animal trial observing ulcerative colitis (UC) in rats discovered that two different forms of calendula extract have significantly high treatment rates. Both extract forms eradicated the inflammation and atrophy caused by UC. 

In a lab-based study, calendula extract exerted anti-inflammatory effects on stomach lining cells. These results occurred due to the inhibition of pro-inflammatory biomarkers.  

The government organization German Commission E recommends calendula for throat and mouth inflammation. 

Respected herbalists Thomas Easley and Steven Horne mention in their herbal text, The Modern Herbal Dispensatory (2014), that “[c]alendula is a wonderful remedy for gastrointestinal inflammation” and may be used specifically for “[c]rohn’s disease, colitis, and gastritis.”

David Hoffmann, registered herbalist of the American Herbalist Guild, writes in his text, Medical Herbalism (2003), that calendula has “anti-inflammatory actions in the digestive system” and could be helpful in ailments like “gastric and duodenal ulcers.”

Famed herbalist, Rosemary Gladstar, writes that calendula is noted for its anti-inflammatory properties and can be applied topically or internally. She also states that calendula is a “wonderful herb for babies” as it gently soothes inflammatory skin conditions like cradle cap and diaper rash.  

2. Antimicrobial Properties  

Another benefit of calendula is its antimicrobial properties.

Recent scientific research backs traditional accounts that calendula has antimicrobial effects. 

Viruses, bacteria, fungi, and parasites are all examples of microbes that can cause various diseases. Natural antimicrobial herbs may clean up existing microbial colonies while inhibiting further growth. 

Research attributes these antimicrobial effects to calendula’s following active constituents; flavonoids, triterpene saponins, and carotenoids.  

A clinical study observing subjects with gingivitis noted that calendula mouthwash significantly reduced dental plaque and inflammation in the gums. This effect was attributed to the reduction of bacteria that causes dental disease.  

In a comparative clinical trial involving participants with mouth stitches, researchers found that calendula mouthwash reduced bacteria levels after seven days of treatment.  

A lab-based study involving numerous gram-positive bacteria species discovered that calendula inhibits bacterial growth.

Another lab-based study observing fungi, gram-positive, and gram-negative bacteria strains noted that various kinds of calendula extracts have antimicrobial activity. While a methanol extract had more potent antibacterial effects than the ethanol extract, both extracts had significant anti-fungal effects.

Herbalist, David Hoffmann, mentions that calendula demonstrates antiviral and antibacterial activity and “may be used both internally and externally to combat fungal infections.”

3. May Promote Wound Healing 

Evidence shows that calendula has promising wound-healing activity. 

Wounds are injuries that occur when the surface of the skin is broken. These injuries can become infected and cause further health issues if they aren’t cleaned and cared for properly. 

A 2016 clinical study observing subjects with diabetic foot ulcers found that calendula extract increased the rate of wound closure. After 30 weeks, 78% of participants experienced complete healing.   

An animal study discovered that calendula extract increases the rate of wound healing in rats with superficial wounds. Researchers attribute the increased rate of healing to an increase in collagen concentration, a biomarker of wound healing. 

A review observing the wound-healing effects of calendula found that calendula speeds up healing time by increasing the production of new connective tissue and blood vessels. Calendula completely healed wounds or reduced wound surface area in all studies.  

Another review of wound-healing medicinal plants mentioned that calendula heals wounds by stimulating connective tissue production.

The German Commission E recommends using calendula for poorly healing wounds and foot ulcers. 

In their herbal text, The Modern Herbal Dispensatory, Thomas Easley and Steven Horne describe topically applied calendula as a common remedy for speeding up “tissue healing after injuries, burns, and bruises.” 

Rosemary Gladstar writes that the “calendula… is a powerful vulnerary, healing wounds by promoting cell repair and growth.”

Well-renowned herbalist, Matthew Wood, notes that calendula “cleans the wound from the inside out”.

4. Antioxidant Properties 

Research shows that calendula may have antioxidant effects.

Antioxidants work to neutralize and eradicate free radicals. Antioxidants are thought to reduce stress, support healthy aging, and benefit overall health. 

A clinical study observing patients with head and neck cancers discovered that calendula extract decreased the intensity of radiotherapy by reducing free radical activity. This research indicates that calendula has antioxidant activity. 

In an animal study, researchers found that calendula extract has liver-protecting effects by decreasing oxidative stress and preventing free radical activity. The affected rats received calendula extract for 6 weeks. 

A lab-based study concluded that Calendula officinalis extract contains antioxidant activity through its ability to reduce oxidative stress and restore cellular balance. 

5. May Support Digestion

Traditionally, calendula has been used as a tonic to promote digestion due to its bitter properties. 

Bitter herbs improve digestion and the absorption of food by increasing bile production in the liver and gall bladder. 

In an animal study, calendula powder and extract improved digestion and increased nutrient absorption in Japanese quail. Quail that ate the extract experienced the most significant weight gain and increased levels of healthy gut bacteria. 

David Hoffmann notes that calendula supports the gall bladder and relieves indigestion. 

Rosemary Gladstar mentions that calendula helps with many stomach issues, including indigestion, cramps, and diarrhea.  

Eclectic physicians Felter & Lloyd (1898) write in their medical text that calendula tastes “somewhat bitter and faintly saline.”

6. May Support the Immune System

Traditional accounts and a few lab-based studies suggest that calendula benefits immune health.

Research suggests that calendula’s active constituents are responsible for this herb’s immunomodulating properties. 

A lab-based study observing tumor cells found that calendula extract may eliminate tumors by increasing the immune system response. Researchers noted that this may be attributed to calendula’s ability to increase the activation of certain immune system biomarkers. 

A review of immunomodulating herbs concluded that Calendula officinalis supports the immune response through the increased production and activation of immune biomarkers. 

Respected herbalist, Juliet Blankespoor, writes that this sunny herb is a wonderful immune tonic when added to soups and stews during the winter months. She suggests adding the entire flowerhead. 

7. Other Benefits

Other calendula benefits include:

• May Stimulate the Lymphatic System: Rosemary Gladstar mentions that calendula stimulates and cleanses the lymphatic system. She suggests taking it alone or including it with other herbal lymphatic cleansers like burdock, red clover, and cleavers. Juliet Blankespoor also mentions calendula’s effects on the lymphatic system, writing that it’s supportive of swollen lymph nodes and stimulates lymphatic flow. 

• May Have Antispasmodic Effects: A lab-based study revealed that calendula extract had an antispasmodic effect by interacting with nerve cells and biomarkers related to body tension.

• May Have Anticancer Activity: A review of calendula mentions that this herb shows promising anticancer potential through its anti-tumor and cytotoxic activity.

Is Calendula Safe?

Safety Class: 1

Interaction Class: A

Calendula is generally recognized as safe (GRAS) by the FDA. 

People should avoid using calendula if they have a sensitivity or allergy to herbs in the Asteraceae family. It is recommended to conduct a skin patch test to check for an allergic reaction prior to using calendula, especially when using a calendula-based diaper balm for babies.  

An allergic reaction is rare, and calendula is generally well-tolerated and safe to use for most individuals. 

The German Commission E has approved calendula for internal and topical use.

Calendula is currently approved for medicinal use by a number of countries, including the United Kingdom, Canada, and the United States.

Pregnancy & Lactation:

Due to a lack of data and the traditional use of calendula to bring on menstruation, it is not recommended to use calendula internally while nursing or pregnant. 

Although internal use should be avoided, modern and traditional accounts suggest that topical use of calendula may be helpful for breastfeeding mothers, specifically for cracked nipples.   

Calendula Dosage:

Standard dosing for calendula is as follows:

Infusion (tea): Add 1 cup of boiling water to 1-2 teaspoons of dried herb and allow to infuse for 10-15 minutes in a covered cup (to capture the beneficial essential oils). Drink 1 cup 3x per/day.

Tincture (1:5): 1-4ml, 3x/day.

Topically (salve, ointment, or lotion) (1:5): Apply generously 3x/day. 

Fluid Extract (1:1): 0.5 to 1 ml, 3x/day.

Is Calendula Sustainable?

Calendula is not on the United Plant Saver’s “at-risk” list and is considered unimpacted by human activities.

Recent cultivation studies have demonstrated calendula’s high potential as a seed oil crop. These studies predict that calendula’s market potential is high.

Naming & Taxonomy:

Calendula’s scientific name is Calendula officinalis, stemming from the Latin word “kalendae” and the Middle English word “calends,” both meaning “first day of the month.” There are around 20 species in the Calendula spp.; however, only Calendula officinalis can be used for medicinal and culinary purposes. 

Calendula officinalis is in the Asteraceae family (i.e. daisy) and is considered a self-seeding annual. The name “calendula” reflects the flower’s constant appearance at the beginning of most months. 

It is native to Southern Europe but has become naturalized in North America. It loves growing in loamy soil and prefers direct sunlight, although it will grow well in almost any soil and partial shade. 

Calendula is easy to identify due to its bright yellow or orange ray floret (flower head) and the characteristic “tooths” or triple ridge at the end of the petal. The “lance-shaped” leaves are pale green and alternate their way up the stem.

Common names of calendula include: Pot Marigold, Golds, Marygold, Ruddes, Mary Gowles,  Oculus Christi, Fiore d’ogni mese, and Solis Sponsa, Scotch-marigold, Fleur de Calendule, Fleur de Tous les Mois, Garden Marigold, Poor Man’s Saffron, and Gold-Bloom.  

Although calendula is often called “pot marigold,” it does not have any relation to garden marigold (Tagetes spp.), as these are ornamental and have no medicinal properties. 

History & Traditional Use:

The herb calendula is steeped in rich traditional history and was a staple among numerous ancient medicine systems. Calendula flowers were used for medicinal purposes, as a dye, and in various cuisines. 

In Italian culture, calendula was enjoyed in the dish risotto and were part of the infiorate, which are floral ground designs created to honor the procession for Corpus Domini.

For centuries, ancient Himalayan cultures have used calendula to support hemorrhoids and wounds. 

Two British herbalists, John Gerard and Nicholas Culpepper (16th – 17th century), have accounts of calendula being used for “swellings” and “insect stings.” During the 19th century, Eclectic Physicians found calendula useful for internal and external ailments, such as stomach ulcers, conjunctivitis, bruises, burns, and wounds. 

Conclusion:

Calendula is one of the most popular herb species cross-culturally and has been a culinary and medicinal staple for centuries. 

Administering, using, or consuming calendula as an infusion, tincture, salve, or edible herb is recommended. 

If you are considering calendula for culinary or medicinal use, it is important to remember that the bright-colored flowers contain the active constituents. It is also recommended to consult a medical practitioner if you want to include a calendula supplement in your daily routine.