One of the weirder symptoms of COVID-19 (hair loss and Covid penis aside) is the disease's ability to take away your sense of smell. Fittingly, there's a weird way to get that sense of smell back: having a big sniff of your own blood.

Around one in five people who get COVID-19 report some level of loss of smell, about eight weeks after being infected. Smell training – sniffing strong smells several times a day over the course of several months – has shown some effectiveness in restoring smell. However, according to otolaryngologist David Rosen of Thomas Jefferson University, even the most effective smell retraining therapies only restore patients' sense of smell by around 35 percent. 

For another potential treatment – being studied at the moment – it's time to snort your own platelets.

Platelet-rich plasma therapy, Rosen explains to Drug Discovery News, has been around for about 40 years. The treatment works by encouraging nerves in the olfactory system to heal themselves.

"If a nerve that goes to the finger and allows it to move gets cut, it probably won’t work again if we put it back together because these nerves can’t regenerate very well," Rosen told Drug Discovery News. 

"But we can regenerate olfactory neurons by jumpstarting the body’s own ability to repair itself with plasma. Platelets have a lot of growth factors that tell the body, 'okay, start making stem cells and start differentiating those into neurons.' Damaged neural tissue is not easy to repair, but in this instance, we get away with it because of the neuroplasticity already in this system."

The treatment takes little widgets made from cellulose and soaks them in the patient's own plasma. The widget is then packed into the back of the nose, as high as possible, where it will reside for some time. In the first minute after this, 80 percent of the platelet-rich plasma is absorbed, while the rest gets slurped up over the next few days.

Rosen is having success with the treatment of COVID-19 patients in a pilot study involving several dozen patients. However, he is aware he needs more data to back up the results he's seen so far, comparing the treatment with those who have undergone smell retraining. His team will soon begin a placebo-controlled study, and hopes to go through a phase II trial soon after that. 

"I saw a patient yesterday who had only received two treatments so far, and she told me that grass smelled like grass to her again and chocolate tasted like chocolate," he added. "I’m excited to see people getting back to their normal lives."