Because cinnamon and cinnamon extracts have demonstrated benefits in people with insulin resistance and type 2 diabetes, it has potential benefits in people with metabolic syndrome.^7,8 A placebo-controlled trial that included 116 participants with metabolic syndrome found 3 grams of cinnamon per day for 16 weeks improved blood glucose, triglyceride, and cholesterol levels, as well as waist circumference, blood pressure, and blood glucose control.⁹ In a randomized controlled trial, cinnamon reduced signs of metabolic disease in people with type 2 diabetes: after eight weeks, study participants receiving 3 grams of cinnamon per day had lower blood glucose levels, triglyceride levels, body weight, and body fat, and improved blood glucose control.¹⁰ Similarly, in a placebo-controlled trial with 140 participants with diabetes, taking 1 gram of cinnamon daily for three months improved glucose and lipid metabolism and was associated with body fat and weight loss, with stronger effects in those with more severe obesity.¹¹ Placebo-controlled trials in people with type 2 diabetes show cinnamon can reduce high blood pressure in people with metabolic disease.^12,13 Furthermore, a meta-analysis of controlled trials showed cinnamon can also reduce high blood pressure, with greatest efficacy when used at a dose of 2 grams per day or less for at least 12 weeks.¹⁴

A number of randomized controlled trials have found adding 1 to 3 grams of cinnamon per day to usual treatment for two to three months can improve blood glucose control and lower HgbA1c in people with type 2 diabetes.^{15,16,17,18,19,20} However, not all studies have reported positive effects.²¹ Two meta-analysis of randomized controlled trials concluded that, although the evidence was difficult to analyze due to differences in study methods, cinnamon appears to lower blood glucose levels, but not HgbA1c, in people with type 2 diabetes.^22,23

 

Carminatives (also called aromatic digestive tonics or aromatic bitters) may be used to relieve symptoms of indigestion, particularly when there is excessive gas. It is believed that carminative agents work, at least in part, by relieving spasms in the intestinal tract.²⁴

There are numerous carminative herbs, including European angelica root (Angelica archangelica), anise, Basil, cardamom, cinnamon, cloves, coriander, dill, ginger, oregano, rosemary, sage, lavender, and thyme.²⁵ Many of these are common kitchen herbs and thus are readily available for making tea to calm an upset stomach. Rosemary is sometimes used to treat indigestion in the elderly by European herbal practitioners.²⁶ The German Commission E monograph suggests a daily intake of 4–6 grams of sage leaf.²⁷ Pennyroyal is no longer recommended for use in people with indigestion, however, due to potential side effects.

 

The essential oil of cinnamon contains various chemicals that are believed to be responsible for cinnamon’s medicinal effects. Important among these compounds are eugenol and cinnamaldehyde. Cinnamaldehyde and cinnamon oil vapors exhibit extremely potent antifungal properties in test tubes.²⁸ In a preliminary study in people with AIDS, topical application of cinnamon oil was effective against oral thrush.²⁹

 

Cinnamon has been used historically for the treatment of various menstrual disorders, including heavy menstruation.³⁰ This is also the case with shepherd’s purse (Capsella bursa-pastoris).³¹ Other herbs known as astringents (tannin-containing plants that tend to decrease discharges), such as cranesbill, periwinkle, witch hazel, and oak, were traditionally used for heavy menstruation. Human trials are lacking, so the usefulness of these herbs is unknown. Black horehound was sometimes used traditionally for heavy periods, though this approach has not been investigated by modern research.

 

Cinnamon has been used historically for the treatment of various menstrual disorders, including heavy menstruation.³² This is also the case with shepherd’s purse (Capsella bursa-pastoris).³³ Other herbs known as astringents (tannin-containing plants that tend to decrease discharges), such as cranesbill, periwinkle, witch hazel, and oak, were traditionally used for heavy menstruation. Human trials are lacking, so the usefulness of these herbs is unknown. Black horehound was sometimes used traditionally for heavy periods, though this approach has not been investigated by modern research.

 

Several gas-relieving herbs used in traditional medicine for colic are approved in Germany for intestinal spasms.³⁴ These include yarrow, garden angelica (Angelica archangelica),peppermint, cinnamon, and fumitory (Fumaria officinalis). These herbs are generally given by healthcare professionals as teas or decoctions to the infant. Peppermint tea should be used with caution in infants and young children, as they may choke in reaction to the strong menthol.