Tests have shown infections drain about 30 percent of male hospital patients' testosterone levels, according to the study.
Experts said this robbed them of their sex drives and increased their risk of falling seriously ill.
Lead author Professor Selahittin Çayan said: "In our study, the mean total testosterone decreased, as the severity of the Covid-19 increased.
"Testosterone is associated with the immune system of respiratory organs, and low levels of testosterone might increase the risk of respiratory infections."
Researchers in Turkey found 51 per cent of men in hospital after testing positive for Covid-19 developed hypogonadism – a condition where their bodies don't produce enough testosterone.
On average, the participants' levels were drained by 30 per cent post-infection to borderline unhealthy levels.
There are fears that it could also be affecting asymptomatic men after two-thirds reported low sex drive – a sign of flagging levels of the hormone.
As well as being key in the development of sex organs and muscle growth, testosterone also helps regulate the immune responses, including fighting viral infections.
The University of Mersin scientists have claimed there is a direct correlation between severe illness and lower testosterone levels.
They believe Covid-19 makes men more vulnerable to its nastier symptoms by hampering their immune systems.
Previous studies have linked low levels to an increased risk of dying from the flu, as well as inflammation, heart disease and high blood pressure.
The new study, published in the journal The Aging Male, looked at 232 male patients who tested positive for coronavirus.
They were divided into three groups - intensive care patients, asymptomatic patients and those who needed standard hospital care.
Prof Cayan added: "The mean total testosterone level was significantly lower in the ICU group than in the asymptomatic group.
"In addition, the mean total testosterone level was significantly lower in the ICU group than in the standard care group.
"Low testosterone is also associated with infection-related hospitalisation and all-cause mortality in male in ICU patients, so testosterone treatment may also have benefits beyond improving outcomes for Covid-19."
Hypogonadism – a condition in which the body doesn’t produce enough testosterone – was found in 113 of the patients.
Pre-coronavirus testosterone levels were only available for 24 of the participants.
But results showed these patients saw their levels drop by a third on average.
The researchers are now calling for all men hospitalised with Covid-19 to have their testosterone levels checked upon admission and say testosterone replacement therapy may be a treatment option for the virus.
Professor Çayan added: "It could be recommended that at the time of Covid-19 diagnosis, testosterone levels are also tested.
"In men with low levels of sex hormones who test positive for Covid-19, testosterone treatment could improve their prognosis. More research is needed on this."
The academic admits the team's study was limited because it did not include a control group of patients with conditions other than Covid-19 to compare with.
This was due to the restrictions placed on the hospital that they were monitoring the patients in, she said.
It comes after a study in May found men with low testosterone levels who contract Covid-19 are at far greater risk of dying from the virus.
Medics at the University Medical Center Hamburg-Eppendorf in Germany looked at 45 laboratory-confirmed COVID-19 patients admitted to ICU.
Thirty-five were men and 10 were women, with seven patients requiring oxygen and 33 of them needing ventilation. Nine men and three women died.
Hormone levels of each patient were assessed on their first day in ICU, before they had received any invasive procedures.
Samples from the COVID-19 patients were tested for 12 hormones, including testosterone and dihydrotestosterone.
Of the male COVID-19 patients sent to ICU at the German hospital, more than two thirds (68.6 per cent) recorded low levels of testosterone.
In contrast, the majority of female patients (60 per cent) had elevated testosterone levels.