Capsaicin Glands

Capsaicin is known for being the substance responsible for the heat in chili peppers. But what IS capsaicin, and what does it look it? Also, does it have any other uses besides turning your mouth into a blazing inferno? These are questions I sought to answer for a recent illustration project about capsaicin glands, during which I got medieval on several jalapeño peppers while setting my face on fire in the process.

What is Capsaicin?

Capsaicin is a pungent, crystalline compound derived from the glands of Capsicum (pepper) plants. Capsicum is a large genus of flowering plants in the Solanceae (nightshade) family, which is native to the Americas. Other common names for Capsicum include – bell peppers, green peppers, sweet peppers, chili peppers, hot peppers, jalapeño peppers, Tabasco peppers, red peppers, and cayenne peppers.

Capsaicin is concentrated in glands located within the pepper’s placenta and inner membranes. Contrary to popular belief, pepper seeds do not contain any capsaicin. Their reputation of being the hottest part of the pepper is due to their attachment to the pepper’s placenta and inner wall. When the pepper is sliced some of the capsaicin glands are also severed so they drench all surrounding structures, i.e. the seeds, in capsaicin.

Placenta and Inner Membranes of a Jalapeño Pepper

Peppers have their own dedicated hotness meter, the Scoville Scale, which is named after its creator, American pharmacist Wilbur Scoville. The Scoville scale is a measurement of capsaicin concentration reported in Scoville heat units (SHU) ranging from 0 (zero heat) to 16,000,000, the hottest, which is pure capsaicin. Bell peppers register on the lowest end of the scale at 0 units, while Jalapeños, which have a reputation for high heat, hit a mere 10,000. If you really to burn check out the Ghost and Carolina Reaper peppers, clocking in at 1,000, 000 and 2,000,000, respectively.

Capsaicin Uses 

As anyone who has cut up a pepper scoring high on Scoville scale can attest, capsaicin is strong irritant to the skin and mucous membranesIn spite of this, when used in a properly formulated topical cream, it has been purported to help relieve pain associated with neuralgia (shingles), rheumatoid arthritis, and muscle sprains or strains. Other uses for capsaicin include self-defense pepper spray,  pesticides, and nutritional supplements. 


My objective for this project was to create an infographic illustrating the location of the capsaicin glands on a hotter capsicum pepper and to showing a microscopic view of its capsaicin glands. I also wanted to list a few medicinal and non-medicinal uses of capsaicin as discussed above.

Research Process 

In summary, my research process was to dissect a bunch of jalapeño peppers, remove their placentas  attempt to locate the pepper’s capsaicin glands under a microscope, and sketch them.

Pretty straightforward, however, keep in mind that once you start cutting through placenta and inner membranes of the pepper capsaicin is released. I wore a long-sleeved shirt, latex gloves and glasses to shield my eyes, however, my exposed cheeks and lips quickly “caught fire”. In retrospect, I probably should have wrapped my face in a bandanna.

After about an hour of carefully shaving off thinner and thinner slices of placenta and membrane, I was finally able to locate a few glands under the microscope. The color of capsaicin has variously been described clear, yellow, orange, and reddish-orange. As you can see in this iPhone shot of jalapeño capsaicin glands at 10x magnification, these were a yellowish-orange.

Capsaicin Glands of a Jalapeño Pepper at 10x Magnification


The final illustration is a digital composition containing informative text with manually rendered sections including: capsicum pepper anatomy (gross and dissected), and a 10x cross section of a pepper showing the capsaicin glands.


The individual illustrations were rendered in a combination of watercolor, colored pencil, and pen and ink. I had trouble deciding how to render the microscopic image and ended up using this article as a guide.

Future Research 

I would love to create more illustrations related to capsaicin, by conducting future research such as:

  • Examining capsaicin glands under a higher-powered microscope to see if there are any structures within them.
  • Examining the capsaicin glands of different pepper varietals under a microscope to see if there are color differences.
  • Creating a medical illustration showing how capsaicin affects the human body.
  • Visiting a Capsicum pepper farm.
  • Exploring the culinary uses of peppers by visiting a hot sauce manufacturing plant to observe the creation process.


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Capsicum. (n.d.). In Wikipedia. Retrieved August 1, 2018, from

Cayenne Diane. (n.d.). Scoville scale [Web log post]. Retrieved August 1, 2018, from

Cayenne Diane. (n.d.). The Scoville scale [Web log post]. Retrieved August 1, 2018, from

Mayo Clinic. (2017, March 01). Capsaicin (Topical Route). Retrieved August 1, 2018, from

Microscope Master. (n.d.). How to sketch a microscope slide [Web log post]. Retrieved August 1, 2018, from

Pubchem. (n.d.). Capsaicin. Retrieved August 1, 2018, from

Storl, W.D. (2016). A curious history of vegetables. Berkeley: North Atlantic Books.




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