For decades, we’ve understood that hormonal processes are largely behind male pattern hair loss. But, a new study has found that some people with male pattern baldness also have inflammation caused by the immune system around their hair follicles. This separate issue could worsen hair loss and reduce the effectiveness of hair loss treatments like finasteride and minoxidil. In this blog, we’ll explain the findings and how this new understanding could help men who haven’t responded well to typical treatments.
What You’ll Learn
Ø Causes of male pattern baldness and established treatments
Ø New research finding signs that inflammation could also cause hair loss
Ø Why this discovery might help explain treatment resistance
Ø How this can help hair loss diagnosis and treatment
What we know about male pattern baldness so far
The long-standing understanding of androgenetic alopecia (AGA), or male pattern baldness to you and me, is that it is caused by hormones. Some men are naturally more sensitive to the hormone dihyrdrotestosterone (DHT), which binds to hair follicles on the scalp and cuts off blood supply, so follicles gradually die and stop growing new hairs. That’s why most treatments work by counteracting these two pathways of hair loss: the reduced blood supply or the excess DHT on the scalp.
The only two licensed treatments for male pattern baldness do exactly that:
Finasteride prevents the conversion of testosterone into DHT, reducing levels to protect the hair follicles from damage.
Minoxidil Spray boosts blood flow to the scalp, delivering blood full of oxygen and nutrients to the follicles so they stay healthy and keep growing new hairs. Most people find that using both finasteride and minoxidil together achieves the best results in stopping hair loss and promoting regrowth.
But new research, published in 2025 in the Journal of Clinical, Cosmetic and Investigational Dermatology, uncovers an explanation for why some people don’t respond well to these clinically-proven treatments.
What the new research found
Researchers found that people with AGA may also have immune inflammation around the hair follicles, a different condition which could contribute towards hair loss and explain a poor response to conventional treatment.
They took skin samples from the scalps of 129 adults with pattern hair loss – one from areas where hair was thinning, and another from unaffected areas. When they looked at the samples under microscopes, they made an interesting discovery: 81% had immune inflammation and early signs of scarring around the hair follicles.
Alopecia, which is an umbrella term for any type of hair loss, can come in many forms including alopecia from stress (telogen effluvium), from certain medications like chemotherapy, and scarring alopecia. The researchers found that a subset of people with AGA may have an overlap of symptoms from a different kind of alopecia (with a rather long and complicated name), called perifollicular infundibulo-isthmic lymphocytic infiltrates and fibrosis (or PIILIF for short).
PIILIF was more common in men aged 44 or older, with advanced hair loss rated 5 or more on the Norwood Scale, who had previously not responded well to treatment. The study showed that treating these people with a combination of AGA-specific treatments, like DHT blockers, plus anti-inflammatory treatments, saw much better results than with AGA treatments alone. With this combination therapy, 67% improved and only 2% had a poor response.
What this means for hair loss treatments
Taking a small sample of scalp skin (a biopsy) can help doctors confirm whether someone has PIILIF, especially if they already show signs that suggest this condition. This is useful for figuring out early on if typical pattern hair loss (androgenetic alopecia) might be happening alongside PIILIF. Knowing this helps patients get treatment that targets both causes of hair loss, which can lead to better results.
Researchers also point out that if a person’s hair follicles are already inflamed, the physical trauma from a hair transplant could make the inflammation worse. Because of this, they recommend doing a biopsy before surgery if the scalp exam looks unusual.
All of our blog articles are reviewed by our Medical Director before publication.
