Sweetener molecule suppresses hair follicles in lab test

New research published in the British Journal of Dermatology has found that applying a common food additive to hair follicles can activate taste receptors and prevent hair growth in lab tests.

While taste receptors are usually associated with tastebuds in the mouth, they are found throughout the body and perform various functions. Although taste receptors have previously been found in the skin, their function is unknown.

In this study, researchers from the U.S. and Germany found that human scalp follicles have a bitter taste receptor called TAS2R4. When stimulated with a natural, stevia-like sweetener, rebaudioside A (or Reb-A), the taste receptor sends signals to the follicles that suppress hair growth.

The signals from TAS2R4 do two things; reduce cell division in the hair follicle and start production of a growth factor, TGF-β2, known to stop hair growth.

In a press release from the journal, Professor John McGrath, Editor-in-Chief of the British Journal of Dermatology, said:

“Activating taste receptors in hair follicles with natural sweetener to prevent unwanted hair growth is not a combination of words I necessarily expected to see before reading this research, and yet here we are. We don’t know for sure that activating these taste receptors in hair follicles could reduce hair growth in people—but it’s the type of research that could one day lead to a new type of hair removal product.

“The concept is that activating the receptors alters the way a hair cycles through its growth phases, promoting what is known as ‘apoptosis’, where the hair follicles start to die, stopping hair growth in its tracks.

“So far, the research has been conducted on donated human scalp skin from hair transplant and facelift patients – an important step will be to see if the findings can be repeated in clinical trials on humans rather than just isolated hair follicles.”

The researchers carefully isolated healthy hair follicles from donated scalp skin, keeping them functioning in a controlled environment, designed to prevent other sources of stimulation which could impact the research. The follicles were then treated with either a high dose of Reb-A, which is known to activate TAS2R4, or a control substance every other day for six days.

By analyzing hair follicles donated by males and females separately, the researchers confirmed that Reb-A works regardless of sex.

The researchers also tested whether carefully blocking TAS2R4 signals would stop the sweetener from preventing hair growth, and it did. This provides further evidence that Reb-A is preventing hair growth by activating TAS2R4, as described by the researchers, rather than by some other unforeseen mechanism.

“Despite the name, and their historical association with tastebuds, taste receptors crop up in unexpected places,” said the study’s lead author Ralf Paus, MD, DSc, in the release. “These findings identify specific taste receptors in human hair follicles, demonstrate they are active, and that they can be triggered to control hair growth. Given that, paradoxically, a sweetener can tickle bitter taste receptors so that they send signals which halt hair growth makes one wonder: Is this ‘the bitter-sweet end of unwanted hair?”

Dr. Paus is a Research Professor of Dermatology and Cutaneous Surgery at the University of Miami.

“Beyond the obvious clinical relevance of our findings, this line of research also poses two intriguing questions,” he said. “We know that these taste receptors can be found in many parts of the body, such as the airways and the gut. If we can regulate TGF-β2, a powerful growth factor, simply by triggering taste receptor signaling, what other processes could be controlled in this way? And since, in real life, we don’t have much natural sweeteners floating through our tissues: which substances do these taste receptors recognize 24/7 in the real life of a hair follicle?”