Cinnamic acid is a natural compound found in many plants and the common spice cinnamon (1, 2).

It may have anti-inflammatory properties and be linked to health benefits, such as lower blood sugar levels, improved memory, and a reduced chance of developing cancerous tumors (1, 2, 3).

This article reviews cinnamic acid, including its benefits, possible side effects, and food sources.

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Cinnamic acid is a natural, protective plant compound found in cinnamon bark, ginseng, whole grains, and honey, among other foods (2).

It’s derived when the amino acid, phenylalanine, is broken down by enzymes (1, 2).

It has over 50 derivatives and is a potential therapeutic compound. A recent study found that it may be comparable to, or even more potent than, standard drugs used to treat some chronic and infectious diseases like tuberculosis (2).

Cinnamic acid also has industrial uses and is a common ingredient in cosmetic products, such as perfumes and skin creams, in which it’s used for its ultraviolet (UV) protection and anti-aging properties (1, 2, 4).

Summary

Cinnamic acid is a naturally occurring compound found in many plants, including cinnamon bark. It has potential therapeutic benefits for chronic and infectious diseases and is a common ingredient in cosmetic products.

Laboratory, animal, and human studies have all indicated that cinnamic acid may offer several health benefits.

May improve gut health

Gut health refers to the physical health of the intestinal tract, including the ability to adequately digest food and absorb its nutrients. It also refers to the gut microbiota, which is the community of bacteria that live in the gut.

Poor gut health and dysbiosis — the overgrowth of “bad” bacteria in the gut — are associated with inflammatory conditions such as cancer, obesity, heart disease, and type 2 diabetes (5, 6, 7).

Cinnamic acid is 1 of 14 spice extracts with prebiotic potential, meaning that it has been shown to promote the growth of “good” bacteria in the gut while suppressing the growth of “bad” bacteria in lab studies (8).

Furthermore, a 2020 study showed that cinnamic acid inhibited the growth of E. Coli (GUS) in the gut — a strain of bacteria associated with food poisoning (9).

May improve memory and brain health

One study in mice with diabetes demonstrated that injections with cinnamic acid improved markers of dementia-related memory impairment (10).

The effect was dose-dependent, which means that the more cinnamic acid that was injected into the mice, the more their memory improved (10).

Another study showed that cinnamic acid has a protective effect over the dopamine-producing neurons in mice with Parkinson’s disease (11).

The loss of dopamine-producing neurons is characteristic of Parkinson’s disease, the second most common age-related neurodegenerative disorder (12).

Cinnamon extracts, including cinnamic acid, may also prevent the buildup of beta-amyloid (Aβ) peptides, which play an important role in the development of Alzheimer’s disease (1, 13).

Although these animal studies show great potential, more human research is needed.

May reduce the risk of developing diabetes

Type 2 diabetes mellitus is a complex metabolic disorder that is prevalent in children and adults (14, 15).

Furthermore, diabetes is an inflammatory condition that is associated with oxidative stress and an increased risk of heart disease (15).

Cinnamic acid has antioxidant and anti-inflammatory properties. It may improve blood markers of diabetes by improving cells’ uptake of glucose and reducing the liver’s production of glucose (16, 17, 18).

Cinnamic acid also improved blood cholesterol levels in mice with diabetes (17).

Other potential health benefits:

Studies show that cinnamic acid may have other health benefits as well:

  • May treat periodontitis. Periodontitis is inflammation of the gum tissue, and periodontal disease has been linked to diseases of the cardiovascular, endocrine, and reproductive systems. One rat study discovered that cinnamic acid reduced inflammation caused by periodontitis and promoted bone growth in the area (19, 20).
  • Potential cancer therapy. Studies have shown that cinnamic acid and its derivatives inhibit cancer-causing proteins and may be an adjunct therapy for the treatment of lung and breast cancers (21, 22).
  • May offer UV protection. Cinnamic acid is a common ingredient in many cosmetic products, in which it’s used to offer UV protection. Cinnamic acid is sensitive to and activated by UV radiation, offering antioxidant benefits (4, 23).
  • May reduce the risk of dengue. Some derivatives of cinnamic acid have larvicidal properties and have been shown to destroy the larvae of the Aedes aegypti mosquito, which transmits dengue, yellow fever, and the Chikungunya and Zika viruses (24).

It’s important to note that many of these studies were performed on isolated human cells in lab studies or on animals, such as mice.

Therefore, well-designed research and clinical trials are needed to confirm whether cinnamic acid would have the same effects in humans (16).

Summary

Cinnamic acid has been associated with various health benefits and may support gut health and memory. It may help prevent neurodegeneration, diabetes, cancer, and periodontal disease. Yet, more research is needed.

Cinnamic acid is generally safe for humans when consumed in the small amounts present in foods.

However, the high concentrations of cinnamic acid found in some cosmetic products can trigger allergic reactions and dermatitis inflammation of the skin in some people (4).

These cosmetics brands are either required to use smaller doses or print a safety warning on the label (4).

There’s also concern that UV filters in cosmetics and sunscreens — including the organic compound cinnamic acid — enter the marine environment and are harmful (25).

Toxic environmental effects to marine organisms, such as sea urchins, fish, coral, and algae, include inhibited growth and reproduction, malformations, and death (25).

Furthermore, there is a potential toxicity concern for cinnamaldehyde — a compound found in cinnamon that can potentially be converted to cinnamic acid in the body (26).

Overall, research data on the safety of cinnamic acid is scant. More research is needed to determine its proper dosage and safety profile.

Summary

Cinnamic acid is generally safe when consumed in the small amounts naturally present in foods. The high concentrations of cinnamic acid in cosmetic products may trigger allergic reactions and be toxic to the marine environment.

Cinnamic acid is naturally found in a range of plants and spices. These plants also provide other essential vitamins and minerals needed for overall good health.

You can get cinnamic acid from (1, 2, 27):

  • cinnamon bark (including bark oil, bark powders, and cinnamon stick)
  • ginseng (Panax ginseng)
  • balsam tree sap
  • fruits
  • vegetables
  • whole grains (cereal grains, rice, wheat bran)
  • honey

There are no known cinnamic acid supplements at this time.

Summary

Cinnamic acid is found in a variety of plant sources, including cinnamon bark and its products, ginseng, fruits, vegetables, honey, and whole grains such as rice, wheat bran, and cereal grains.

Cinnamic acid is a natural compound found in a variety of plants sources, including cinnamon bark.

It’s linked to many potential health benefits, including reduced inflammation, lower blood sugar and cholesterol levels, improved memory, and the increased growth of “good” gut bacteria.

While scant data exists on its safety, it appears to be safe when consumed in the small amounts naturally found in foods. That said, there are potential allergy and toxicity risks related to the high concentrations of this compound found in cosmetic products.

More research is needed on the use of cinnamic acid.