Cayenne Pepper: Will It Speed Up Your Metabolism and Shed Pounds?

Cultures across the world eat spicy foods – and for some the hotter, the better. Many enjoy the pain caused by eating hot peppers; it can come with a sense of pleasure and even euphoria. Beyond the heat of a curry or the latest fiery cocktail, people have turned to taking capsaicin (found in cayenne pepper) as a way to lose weight. They’re hoping cayenne pepper will burn calories, speed up their metabolism, and help them shed those extra pounds.

Let’s take a closer look at what the capsaicin found in cayenne peppers can do for you – and whether it delivers on this promise.

Cayenne For Medicinal Use

Hot pepper has been used as medicine for centuries in countries and civilizations across the globe. It is mainly used for pain relief, as a digestive aid, to stimulate blood circulation, for toothaches, and as a remedy for coughs and colds.

Throughout history it’s been applied topically, included in infusions, and eaten in food. Today we have even more ways to apply it, including nasal sprays and dermal patches.

Chili peppers are one of the major sources of carotenoids, as well as precursors of vitamins A and C (ascorbic acid). They contain mostly B vitamins and are particularly high in B5. They’re also rich in potassium, magnesium, iron, calcium, and phosphorus. (1)

Weight Loss

There’s a popular assumption that people who eat spicy foods are thin, but this stereotype isn’t accurate. Many observations, theories, and studies have been made regarding the effect of capsaicin and its potential role in weight loss.

Here’s a breakdown of some key observations and theories regarding what might be happening in our bodies when we consume foods or supplements containing capsaicin:

1. Capsaicin triggers thermogenesis

Thermogenesis, the production of heat in the body, can increase the number of calories burned. And that’s where things get interesting. With hot peppers, it’s all about the perception of heat – and how perception can create reality.

Excess heat activates receptors called TRPV1 (Transient Receptor Potential Cation Channel Subfamily V Member 1); their main function is to help us avoid pain and heat (2). But actual heat isn’t the only trigger. Consuming cayenne, or anything containing enough capsaicin, activates these receptors in your mouth and gut. Your body reacts as if it’s hot: your heart beats faster, your blood flow increases, and you may even start to sweat. And in a strange twist, all this work can increase the heat in your body.

Another mechanism may also be at play. Brown fat cells (technically brown adipose tissue or BAT) burn calories to generate heat and maintain your body temperature, especially when you’re cold. Researchers believe that these cells also pick up the signals from TRPV1, possibly causing an increase in energy expenditure and the potential to “burn” more fat and lose weight.

So what do the studies say? Is this a good way to increase your brown fat and burn more calories?

What does the research say?

In 2016, an 8-week double-blind study looked specifically at the effects of capsinoids on brown fat in 20 volunteers. The results were promising. Those who were given capsinoids had more brown fat at the end of the study than at the start. Unfortunately, the effects disappeared when they were evaluated during the 8-week follow-up. (3) So, eating spicy food for a while might increase your brown fat, which might help you burn more calories. But the effect doesn’t seem to last long after you stop.

Other studies have shown a slight increase in energy expenditure after consuming capsaicin. However, the results overall have been short-lived. (4)

It’s also been shown that TRPV1 receptors build tolerance over time, meaning that those who regularly eat spicy food will eventually tolerate higher levels of heat. This also makes it difficult to establish an effective dose for weight loss.

2. Capsaicin suppresses appetite

Researchers believe that when you eat capsaicin, it interacts with capsaicin-sensitive “visceral afferents” in the stomach and intestines. These are specialized nerves that detect the presence of capsaicin and send signals to the arcuate nucleus, the area in the brain that regulates hunger and satiety. They theorize that this can suppress appetite by stimulating a feeling of fullness.

But when they put their theory to the test, they got quite the surprise.

In a 2106 study, researchers looked at whether capsaicin influences gastrointestinal peptides such as glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) to increase feelings of fullness (satiety). It was a small randomized, double-blind study of 13 healthy participants. (5)

The results were similar to other studies: participants felt more satiated when they took capsaicin. But when they investigated the cause of that satiety, expecting to find evidence, they found something else entirely. Those feelings of fullness were associated with a stressed gut, pain, and nausea.

Not exactly what they were expecting!

3. Capsaicin influences the gut microbiome and obesity

There’s evidence connecting both an unhealthy gut microbiome and a malfunctioning gut-brain axis to obesity (3). Less microbial diversity and an increase in harmful bacteria such as Firmicutes have also been linked to obesity. On the other hand, an abundance of Akkermansia muciniphila (considered to be “good” bacteria) is inversely correlated with obesity and type 1 diabetes in both mice and humans (6).

Capsaicin has been reported to increase the Akkermansia muciniphila population and to reduce the number of Gram-negative lipopolysaccharides (LPS). These polysaccharides have been shown to produce chronic low-grade inflammation, and they’re also linked to obesity (4).

In a recent study on mice, researchers found that capsaicin’s effect on body weight was associated with a modest modulation of gut microbiota. They suggested that changes in the gut microbiome and the increase in the Akkermansia population might play a key role in this effect. However, the authors also pointed out that the mechanisms involved in these changes were not yet clear and that further studies are needed. (6)

In other words, don’t get excited yet. Capsaicin is certainly interesting, but it’s not the answer to weight loss.

Incorporating Cayenne Pepper into Your Diet

Whilst the studies aren’t showing great promise when it comes to weight loss, that doesn’t mean spicy food is without its benefits. And there’s certainly no shortage of ways to incorporate cayenne pepper into your meals.

Whether fresh, dried, or pickled, the possibilities are endless, from salsas and guacamoles to marinades, stews, and curries. A pinch of cayenne can also bring an unexpected kick to cocktails, lemonade, or even chocolate drinks and desserts.

Potential Side Effects and Cautions

Excessive capsaicin intake can cause digestive discomfort, heartburn, and stomach irritation.

Capsaicin can potentially interfere with certain medications. It’s important to be aware of these interactions before consuming large amounts of cayenne pepper or taking capsaicin supplements while on medication or having a pre-existing health condition. It’s always best to consult with your medical professional or pharmacist to be sure.

The Big Picture

Whilst cayenne pepper may have some medicinal value, it’s no magic bullet for weight loss. Sustainable weight loss requires a holistic approach that includes eating a healthy diet, engaging in regular physical activity, and modifying other risk factors such as stress and poor sleep.

References

1. Saleh BK, Omer A, Teweldemedhin B. Medicinal uses and health benefits of chili pepper (Capsicum spp.): a review. MOJ Food Process Technol. 2018;6(4):325-328. DOI: 10.15406/mojfpt.2018.06.00183

2. Azlan A, Sultana S, Huei CS, Razman MR. Antioxidant, Anti-Obesity, Nutritional and Other Beneficial Effects of Different Chili Pepper: A Review. Molecules. 2022 Jan 28;27(3):898. doi: 10.3390/molecules27030898. PMID: 35164163; PMCID: PMC8839052.

3. Nirengi S, Homma T, Inoue N, Sato H, Yoneshiro T, Matsushita M, Kameya T, Sugie H, Tsuzaki K, Saito M, Sakane N, Kurosawa Y, Hamaoka T. Assessment of human brown adipose tissue density during daily ingestion of thermogenic capsinoids using near-infrared time-resolved spectroscopy. J Biomed Opt. 2016 Sep;21(9):091305. doi: 10.1117/1.JBO.21.9.091305. PMID: 27135066.

4. Szallasi, A. Capsaicin for Weight Control: “Exercise in a Pill” (or Just Another Fad)? Pharmaceuticals 2022, 15, 851. https://doi.org/10.3390/ph15070851

5. van Avesaat M, Troost FJ, Westerterp-Plantenga MS, Helyes Z, Le Roux CW, Dekker J, Masclee AA, Keszthelyi D. Capsaicin-induced satiety is associated with gastrointestinal distress but not with the release of satiety hormones. Am J Clin Nutr. 2016 Feb;103(2):305-13. doi: 10.3945/ajcn.115.123414. Epub 2015 Dec 30. PMID: 26718419.

6. Shen W, Shen M, Zhao X, Zhu H, Yang Y, Lu S, Tan Y, Li G, Li M, Wang J, Hu F, Le S. Anti-obesity Effect of Capsaicin in Mice Fed with High-Fat Diet Is Associated with an Increase in Population of the Gut Bacterium Akkermansia muciniphila. Front Microbiol. 2017 Feb 23;8:272. doi: 10.3389/fmicb.2017.00272. PMID: 28280490; PMCID: PMC5322252.