Why Hair Falls Out More After Stopping Hair-Loss Medication [Kim Jin-oh’s Escape from Hair Loss]

[Financial News]  Anyone who takes hair-loss medication for several years and then stops would be thrown into considerable confusion if their hair began falling out at an unmanageable rate. Recently, a plausible-sounding theory about this phenomenon has been circulating in domestic and international hair-loss communities. It holds that suppressing male hormones (dihydrotestosterone, DHT) with medication causes scalp follicles to respond to the hormone deficiency by abnormally increasing androgen receptor (AR) levels, and that once the medication is discontinued, the hair becomes hypersensitive to the hormones and falls out as though it were melting away—a so-called theory of "receptor upregulation." This hypothesis has fueled widespread anxiety in these communities that the medication makes the follicles inherently vulnerable. However, it is far from medical fact.

The background to this claim lies in the treatment mechanisms used for prostate cancer. Human cells tend to increase the number of receptors when stimulation by a particular hormone decreases, allowing them to receive more signals. In fact, when prostate cancer patients undergo treatment that depletes male hormones, cancer cells amplify androgen receptor genes or develop mutations in order to survive. Some people with hair loss have inappropriately extrapolated this mechanism from advanced oncology to scalp follicles. Because 5-alpha-reductase inhibitors lower DHT, the argument makes the logical leap that dermal papilla cells will increase their receptors and resist treatment like cancer cells.
However, normal scalp follicles are not malignant tumors that mutate their genes to survive. More importantly, this theory directly conflicts with extensive long-term clinical data. If receptor upregulation made follicles hypersensitive to hormones, patients who stopped taking the medication would have to experience continued excess hair loss far beyond that seen in people who had never taken it. Yet in a five-year finasteride clinical trial, patients who took the medication for one year and then switched to a placebo were followed over time. Their hair counts fell sharply after discontinuation, but the decline stopped at exactly the point where it matched the hair-count curve of the placebo control group, which had taken no medication for two full years. The medication did not damage the follicles; rather, hair simply returned to the natural genetic progression it would have followed without treatment.

Why, then, does the person believe that their hair is falling out abnormally? The source of that anxiety is not runaway receptors but "synchronization of the hair cycle" and "time compression." While taking hair-loss medication, hairs that would have gradually thinned and fallen out remained artificially attached to the scalp thanks to the drug’s effects. When the medication is stopped and DHT returns to its natural level, these hairs lose their individual cycles and simultaneously enter the resting phase. Hairs that should have fallen out gradually over three or five years are compressed into a period of several months and shed all at once. 
Studies tracking patients for more than 10 years have also found no receptor resistance or irreversible hypersensitivity caused by hair-loss medication. The perception that the medication’s effectiveness has waned during long-term use is likewise not due to receptor changes. Rather, the natural aging of the follicles and the genetic pressure that progresses with age gradually outpace the medication’s ability to sustain them. Therefore, there is no need to search for unverified hormone-blocking methods or folk remedies simply because hair pours out after stopping the medication. The follicles’ receptors have not been damaged; it is a temporary overlap in shedding caused by delayed hair cycles. I hope this does not create unnecessary anxiety that prevents people from even trying the medication.

/Kim Jin-oh, Chief Director of Kim Jin-oh New Hair Hair Transplant Clinic
[email protected] Kim Hyeon-seon Reporter