A tsawon tarihi, an danganta asalin namiji da babban sinadarin testosterone na namiji. A lokacin da yake da shekaru kusan 30, matakan testosterone suna fara raguwa kuma wannan na iya haifar da wasu canje-canje mara kyau ga lafiyarsa da walwalarsa: raguwar aikin jima'i, ƙarancin kuzari, raguwar tsoka da ƙaruwar kitse, da sauransu.
Ka haɗa wannan da gurɓatattun muhalli marasa iyaka, damuwa da rashin abinci mai gina jiki wanda ya zama ruwan dare a yawancin rayuwarmu kuma ba abin mamaki ba ne cewa muna ganin annobar ƙarancin sinadarin testosterone a cikin maza a duk faɗin duniya.
A shekarar 2013, wani gungun masu bincike na Koriya sun yi nazari kan tasirin fallasa ga ƙwai ga mazakutaHasken laser ja (670nm) da infrared (808nm).
Masana kimiyyar sun raba beraye maza 30 zuwa rukuni uku: ƙungiyar masu kula da beraye da kuma ƙungiyoyi biyu da aka fallasa ga hasken ja ko infrared. A ƙarshen gwajin na tsawon kwanaki 5 inda aka fallasa beraye ga magani na minti 30 a rana, ƙungiyar masu kula da beraye ba ta ga wani ƙaruwa a cikin testosterone ba kuma an gano cewa matakan testosterone a cikin beraye masu fallasa ja da infrared sun ƙaru sosai:
"...Matsayin T na jini ya ƙaru sosai a cikin rukunin raƙuman ruwa na 808nm. A cikin rukunin raƙuman ruwa na 670nm, matakin T na jini ya kuma ƙaru sosai a matakan testosterone a daidai wannan ƙarfin na 360 J/cm2/rana."