This article launches a new monthly series highlighting important new research on smell loss and smell disorders. I review the scientific literature every week, and the aim of this series is simple: to identify the studies that genuinely matter for people living with smell loss, distorted smell, or changes in how they experience scent, and explain them in clear, plain language.
This month, three very different papers stood out. Together, they help explain how smell can be treated, how recovery might be improved, and why smell plays such a powerful role in our emotional lives.
A promising, but still experimental, treatment: PRP for smell loss
The first paper looks at platelet-rich plasma, or PRP, as a possible treatment for people with long-term smell loss. PRP is made from a person’s own blood and contains growth factors that help support healing. It is already used in other areas of medicine, and researchers are now exploring whether it can help repair the smell system.
This review brought together results from seven studies involving almost 800 adults who had experienced smell loss for more than six months and had not improved with standard treatments such as nasal sprays or smell training. Across the studies, people who received PRP generally showed greater improvement than those who received a placebo or no treatment. Some participants noticed improvement within a month, and in some cases benefits lasted up to a year.
Younger people, particularly those under 40, tended to improve more than older adults. This may be because younger nerves are better able to regenerate. Side effects were usually mild and short-lived, including nasal discomfort or minor nosebleeds.
Despite these encouraging findings, PRP is not a guaranteed solution. The studies varied widely in how PRP was prepared and delivered, and most participants had COVID-related smell loss. For now, PRP should be viewed as promising but still experimental, and generally considered only after standard treatments have not helped.
Smell training works, and there may be a smarter way to do it
The second study focused on smell training, which remains the most widely recommended therapy for smell loss.
Participants with post-viral smell loss were divided into groups. Some trained with the same four scents for six months, some switched to new scents halfway through, and one group combined smell training with visual cues by looking at images of what they were smelling. A control group sniffed an odourless substance.
All of the smell-training groups improved more than the control group, confirming that smell training does help. The group that combined smelling with looking showed the strongest and fastest improvement. Adding visual cues likely helps by engaging more parts of the brain during learning.
Interestingly, using a larger number of scents did not lead to better final outcomes. Women and people with higher levels of education tended to improve more, suggesting that attention, memory, and learning style play a role. Mood and quality-of-life scores did not change much during the study, which is a reminder that emotional recovery often lags behind sensory recovery.
Why smell is so emotional, and why losing it hurts
The third paper takes a broader view and asks why smell feels so deeply emotional.
The author argues that smell and emotion are closely linked, perhaps even inseparable. Smell is processed in brain areas directly connected to emotion and memory, which helps explain why a single scent can instantly trigger comfort, joy, sadness, or grief.
Our responses to smell are highly individual. Genetics influence what we can smell and how strongly, while life experiences and culture shape what those smells mean to us. This helps explain why the same scent can feel comforting to one person and unpleasant to another.
The paper also sheds light on why smell loss can be emotionally distressing. Smell loss is associated with higher rates of depression, anxiety, and social withdrawal. At the same time, emotional states such as anxiety and low mood can affect how well we smell. Smell and emotional health influence each other more than many people realise.
You can read more about the connection between smell loss and mental health here.
Key takeaway
Taken together, these studies reinforce a clear message: smell matters. It can be treated, trained, and better understood, and doing so has real implications for quality of life and mental wellbeing.
In future editions of this series, I will continue reviewing new research on smell loss to highlight what is emerging, what looks promising, and what people living with smell disorders need to know.
