Stevioside microneedle patches could boost minoxidil for androgenetic alopecia (AGA)

Minoxidil, one of the best-known treatments for androgenetic alopecia (AGA) – the typical pattern hair loss – may be made more effective by adding stevioside, a natural sweetener taken from the stevia plant (Stevia rebaudiana).

Why minoxidil treatment for androgenetic alopecia (AGA) can be limited

Minoxidil is commonly applied by rubbing it into the scalp. It is thought to help re-energise hair follicles by improving blood flow, yet only a relatively small amount is absorbed through the skin. To increase how much reaches its target, researchers have been exploring different types of microneedle patches to improve penetration.

Stevioside microneedle patches to improve minoxidil delivery

In a new study, scientists in China and Australia paired microneedle patches with stevioside, largely because stevioside allows minoxidil to dissolve far more readily in water. With better solubility, the technique is expected to deliver substantially more minoxidil beneath the skin and down to the hair follicles.

Results from genetically engineered mice

The team tested the strategy in mice that had been genetically engineered to lose hair. The findings were encouraging: a much larger amount of minoxidil entered the skin, and hair regrowth increased.

"There is a significant increase in hair follicle transition to the growth phase, which resulted in 67.5 percent coverage of the treatment area by day 35," write the researchers in their paper.

"Collectively, the results highlight the potential of the stevioside microneedle delivery system for the treatment of AGA."

By contrast, mice given a standard minoxidil solution reached just 25.7 percent coverage by day 35. The researchers also observed that regrowth began roughly a week sooner with the microneedle approach.

Next steps before use in people

Despite the positive outcome, the work relates to mouse hair rather than human hair. The researchers are continuing to refine both the microneedle delivery system and the minoxidil formulation to determine the most effective way to administer it.

"The benefits and drawbacks of various technical methods, such as metal or soluble microneedles and sustained-release systems, should be evaluated in conjunction with specific clinical scenarios," write the researchers.

Before any human clinical trials can begin, the method will need to be tested in larger animals. Only then can scientists judge how these microneedle patches might perform in people, while also assessing potential side effects or other complications.

Long-term practicality will also require investigation. Current minoxidil regimens typically require application at least once a day; microneedle delivery could alter that, but it must still be appropriate for repeated, regular use.

"Using stevioside to enhance minoxidil delivery represents a promising step toward more effective and natural treatments for hair loss, potentially benefiting millions worldwide," says pharmacologist Lifeng Kang, from the University of Sydney in Australia.

The research has been published in Advanced Healthcare Materials.