This study is exploring if a nasal spray called sodium citrate can help people who lost their sense of smell after having COVID-19. Sometimes, people lose their sense of smell because of a virus, and this can cause problems like not being able to smell things like gas leaks or spoiled food. The study will see if using sodium citrate spray, along with a special smell training, can help improve their sense of smell.

Sodium citrate is a compound that may help by affecting how smell signals work in the nose. Participants will use either sodium citrate spray or a regular saltwater spray (called normal saline) twice a day and do smell training for 12 weeks. Smell training involves sniffing certain scents like lavender and lemon.

• This study lasts for 12 weeks, with follow-ups using "Sniffin' Sticks" to test smell.
• Nasal sprays will be provided, and participants' use will be checked monthly.
• You must be over 18, have had COVID-19, and lost your sense of smell for over three months to participate.