A Whiff of Genius: Simple Fragrance Method Boosts Cognitive Capacity by 226%

Old Man Inhaling Scent

Research found that senior citizens exposed to specific scents nightly showed a 226% memory boost. This highlights the potent link between smell and memory, presenting a potential tool against dementia. A related product is launching this fall.

Sweet Smell of Success: Simple Fragrance Method Produces Major Memory Boost

When a fragrance wafted through the bedrooms of older adults for two hours every night for six months, memories skyrocketed. In fact, participants in this study by neuroscientists from the University of California, Irvine (UCI), reaped a 226% increase in cognitive capacity compared to the control group. The researchers say the finding transforms the long-known tie between smell and memory into an easy, non-invasive technique for strengthening memory and potentially deterring dementia.

The team’s study was published recently in the journal Frontiers in Neuroscience.

Study Details and Results

The research project was conducted through the UCI Center for the Neurobiology of Learning & Memory. It involved men and women aged 60 to 85 without memory impairment. All were given a diffuser and seven cartridges, each containing a single and different natural oil. People in the enriched group received full-strength cartridges. Control group participants were given the oils in tiny amounts. Participants put a different cartridge into their diffuser each evening prior to going to bed, and it activated for two hours as they slept.

People in the enriched group showed a 226% increase in cognitive performance compared to the control group, as measured by a word list test commonly used to evaluate memory. Imaging revealed better integrity in the brain pathway called the left uncinate fasciculus. This pathway, which connects the medial temporal lobe to the decision-making prefrontal cortex, becomes less robust with age. Participants also reported sleeping more soundly.

The Power of Smell and Memory

Scientists have long known that the loss of olfactory capacity, or ability to smell, can predict the development of nearly 70 neurological and psychiatric diseases. These include Alzheimer’s and other dementias, Parkinson’s, schizophrenia, and alcoholism. Evidence is emerging about a link between smell loss due to COVID and ensuing cognitive decrease. Researchers have previously found that exposing people with moderate dementia to up to 40 different odors twice a day over a period of time boosted their memories and language skills, eased depression, and improved their olfactory capacities. The UCI team decided to try turning this knowledge into an easy and non-invasive dementia-fighting tool.

“The reality is that over the age of 60, the olfactory sense and cognition starts to fall off a cliff,” said Michael Leon, professor of neurobiology & behavior and a CNLM fellow. “But it’s not realistic to think people with cognitive impairment could open, sniff, and close 80 odorant bottles daily. This would be difficult even for those without dementia.”

The study’s first author, project scientist Cynthia Woo, said: “That’s why we reduced the number of scents to just seven, exposing participants to just one each time, rather than the multiple aromas used simultaneously in previous research projects. By making it possible for people to experience the odors while sleeping, we eliminated the need to set aside time for this during waking hours every day.”

The researchers say the results from their study bear out what scientists learned about the connection between smell and memory.

The Unique Role of Olfactory Sense

“The olfactory sense has the special privilege of being directly connected to the brain’s memory circuits,” said Michael Yassa, professor and James L. McGaugh Chair in the Neurobiology of Learning & Memory. The director of CNLM, he served as collaborating investigator. “All the other senses are routed first through the thalamus. Everyone has experienced how powerful aromas are in evoking recollections, even from very long ago. However, unlike with vision changes that we treat with glasses and hearing aids for hearing impairment, there has been no intervention for the loss of smell.”

The team would next like to study the technique’s impact on people with diagnosed cognitive loss. The researchers also say they hope the finding will lead to more investigations into olfactory therapies for memory impairment. A product based on their study and designed for people to use at home is expected to come onto the market this fall.

Reference: “Overnight olfactory enrichment using an odorant diffuser improves memory and modifies the uncinate fasciculus in older adults” by Cynthia C. Woo, Blake Miranda, Mithra Sathishkumar, Farideh Dehkordi-Vakil, Michael A. Yassa and Michael Leon, 24 July 2023, Frontiers in Neuroscience.
DOI: 10.3389/fnins.2023.1200448

The study was supported by Procter & Gamble.

89 Comments on "A Whiff of Genius: Simple Fragrance Method Boosts Cognitive Capacity by 226%"

  1. This is very exciting. I’m 80, and I’ve definitely experienced a decrease in my memory over the last few years. It’s hard to imagine a more pleasant treatment. I’m looking forward to experiencing it!

  2. Can anything be done if a person must use a C-PAP? Especially when that same person, decades ago, lost most of their sense of smell due to a severe sinus infection.

    • I use a bipap machine but I would think you would still get benefits of it because it uses the air in your room. I can’t smell or taste either but i assume it is getting to me through machine

      • I’m reading the same information you all are and there isn’t any mention of the specific oils used. I personally like peppermint eucalyptus, francensence, mandarin, and tea tree

        • Yeah, I noticed that as well and I’m sure it was intentional for the specific purpose of garnering interest from people so that huge profits can be made in the future.
          The sad truth in today’s world is that no information which could instantly improve people’s health and happiness is just shared to help everyone but instead is marketed in a way to maximize the profits and feed someboy’s greed.
          If you want to know why a person or company is doing something just follow the money and it will tell you why.

    • It may not be getting through the CPAP machine due to the filtration. However, if this study proves correct then CPAP device design can easily be changed to allow the use of scent. It’s just a matter of manufacturer engineering. Now whether it will or not be changed is a different matter.

  3. Geoffrey Bryant | September 3, 2023 at 4:29 am | Reply

    What are the effective substances and where can I obtain them and the diffuser?

    • Amazon sells oils and diffusers.

      • I think she was asking for clarification since they didn’t give any particular information as to what scent work best

        • Neither this article or the linked research article list the actual oils used. The research is funded by Protor and Gamble, so I can imagine the actual oils will either be only described once P&G patents and markets their diffuser oils. Time will tell if they will actually list the oils, or just proprietary blends. Science at work folks, totally ethical and unbiased. /s

          • Thanks Josh. I kept reading, saying to myself ‘get to the scents already’.Good to know I didn’t miss them.

          • Please keep me posted on this research
            I want to sell this new product and use it myself
            thank you

          • Robert Uomini | May 23, 2024 at 8:49 am |

            No secret. The article didn’t post the scents, but the researchers did in their paper: https://www.frontiers in.org/journals/neuroscience/articles/10.3389/fnins.2023.1200448/full
            As you can see, the scents are indeed listed.

        • I was able to find the abstract. I’ve included links to the abstract and products used as well as the relevant passage as to specific scents used and how and where they were obtained. My understanding, however, is that they are basic essential oils, which could be purchased anywhere (provided they are of comparable quality):
          “Individuals assigned to the olfactory enrichment group were provided with an odorant diffuser (Diffuser World) and 7 essential oil odorants (rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender; from The Essential Oil Company, Portland, OR) in identical glass vials that each fit into the diffuser. They were asked to turn on the diffuser when they went to bed, and the odorant was released into the air during the night for 2 h when they first went to sleep. They rotated through the different odorants each night.”

          • Thank you for doing the research and sharing it. I’m passing it onto to all friends and family. May your life be blessed as much as possible!

          • Robert Uomini | May 23, 2024 at 8:52 am |

            Right. Unfortunately, the diffuser used in the study has been back ordered by Diffuser World for at least 6 months now.

    • Lemon essential oil is a powerful one.

      • Be careful of Tea tree oil. Very strong! My dog and I cough as soon as I sprayed diluted tea tree oil. I also get a instant headache when I smell strong Tea Tree Oil

    • It would be best to look into naturally sourced oils. The effects of aromatherapy have long been known dating further back than Egyptian times. There’s a lot of oils that contain toxins. Be mindful of this in your search.

    • Geoffrey, I did a bit of searching and found this article on frontiers: https://www.frontiersin.org/articles/10.3389/fnins.2023.1200448/full .
      It describes the fragrances used as “four odorants that represented the resinous, flowery, fruity, and aromatic odor groups”. The groups are further described on another site as “rose (representing flowery), lemon (fruity), aromatic (cloves), and resinous (eucalyptus)”. At 60 this technique is something I will be testing myself.

      • Thank you, Blake, for your diligent research. I was shaking my head wondering what they would settle on the use. I expected a lavender too, but those are some of the others I thought of.

    • Donna Robertson | September 5, 2023 at 6:26 am | Reply

      What are the seven oils to be used for this purpose. It is not noted on the web page. Thank you very much

  4. Will try again . . .
    What can be done for someone who must use a C-PAP? That same person lost most of their sense of smell due to a bad sinus infection decades ago?

    • Few drops of ammonia in the lemon oil.

      • Ammonia is very toxic & exposure over time leads to throat,lung,neurological dysfunction by cellular swelling, brain edema & metabolic dysfunction. Eventually death

    • I have family who use C-PAPS & believe the only option is a diffuser in the day. The essential oils need to be something soothing to the person & trigger good memorories. My 88yo Mom & I use eucalyptus, peppermint or wintergreen w/ a few drops of lemon for sinus/breathing. But I would type in this request on websites of Cleveland or Mayo Clinic. Cleveland has Dr Mark Hyman now,who’s written many researched books on healing w food, herbs, natural supplements & products

    • Use it during the day. The article says it’s administered at night for convenience, not necessity.

  5. What can be done for someone who must use a C-PAP? That same person lost most of their sense of smell due to a bad sinus infection decades ago.

    • Michael W. Clark | September 3, 2023 at 7:47 am | Reply

      I had the same problem with c-pap machines, and a sinus infection on one side.

      I stopped using the c-pap machine and learned to sleep only on my side with a ceiling fan on high, and a pillow over my head to lower the sound. A pillow between the knees helps too. The fan keeps changing the air, so the CO2 does not pool around your face.

    • Alison vanZandbergen | September 4, 2023 at 3:12 pm | Reply

      If you read the book Breath by James Nestor you can get lots of insights on all the comorbidities that go along with people on C-Pap and others too. Applying what the author shares has been positively transformational for many of my friends, patients, and myself (even though I wasn’t a snorer).

      • This is just a side note regarding my personal experience that is completely coincidental however I wish that I had realized how potent essential oils can be, prior to using a sinus spray that is made by Vicks. I had used it one time, as directed, after an overly emotional evening. Simply put I had been crying for some length of time and was having a hard time breathing. I was not seeking out any particular essential oil. After falling asleep, I awoke later to a very sore upper lip.In fact, the abrasion was so severe that I wondered if I had fallen asleep while smoking a cigarette. Which is something that had happened years ago, after mixing my medications. My finger was burnt then though. At this rate, I knew that was not what happened. I believe after my sinuses cleared, my nose was running as I slept. Point being – eucalyptus oil, while diluted and used properly- can have side effects for weeks. I was unsure until reading this that was exactly what occurred, but as a woman with no facial hair- I could not hide a huge red burn that lasted weeks. It was the “vapocool” sinus spray, that I would not use directly on skin if looking for relief of any kind. I’m not sure how else to word the incident, and could not be relevant to anyone. I just wish I’d read articles that are both linked above. Benzos specifically are so hard to use and get both instant anxiety relief and be functional. This being a medical blog,I assume others with the same issues or circumstances will take note. After a particularly rough month – I’m reassessing my personal
        treatment. I’m not ok with having such a severe reaction to a combination of circumstances and side effects that I will come upon regularly.

    • Use it during the day. The article says it’s administered at night for convenience, not necessity.


  7. Which essential oil scents are used?


  8. Researching more to find actual strength of oil used. Diffusers and essential oils available on Amazon.
    Please share strengths used.

  9. Just be careful if you have pets! Most cats, as I understand it, have very bad reactions to most oil diffusers.

  10. How do we find this scent? My husband has moderate dementia at 74 and is being treated with oral meds. I am 71 and realize my memory isn’t quite as good as it was a decade ago. I have multiple diffusers waiting!

  11. Individuals assigned to the olfactory enrichment group were provided with an odorant diffuser (Diffuser World) and 7 essential oil odorants (rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender; from The Essential Oil Company, Portland, OR) in identical glass vials that each fit into the diffuser.


  12. Was it all 7 essential oils put into diffuser? Or one of them that boosts memory?

    • One at a time.

    • I think it’s the variety of scents that challenges/triggers the brain. That’s why they alternate them.

    • Many scents help exercise memory.as does certain types of music. Like the four seasons for example . I use rosemary oil and ylang-ylang and lavender . When relaxed you recall better .really a lot is down to genetics and having a healthy upbringing with healthy foods Brest fed babies are more resilient

  13. Fight Club Meets in the Basement | September 3, 2023 at 6:46 am | Reply

    There was no breakdown showing which, if any, oil was better for memory than the others?

    If they were all equal, then it’s the olfactory sensing itself producing the effect.

  14. Cadmon Edmundsen | September 3, 2023 at 6:53 am | Reply

    The Proctor and Gamble-funded study (N=23 healthy Irvine, CA residents, ages 60-85, average of 16 years of education, with 11 of the 23 as controls) provided “an odorant diffuser (Diffuser World) and 7 essential oil odorants (rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender; from The Essential Oil Company, Portland, OR) …. Participants were instructed to change the odorant bottle daily before they went to bed, and they continued this regimen at home for 6 months.“ Only one of eight outcomes for the Rey Auditory Verbal Learning Test was statistically significant.

  15. Nice to here the news, but the article not complete because it doesn’t supply information on diffuser or scents and fragrances used.

  16. Michael W. Clark | September 3, 2023 at 7:56 am | Reply

    I suspect that dementia is relate to retirement, and isolation from new stimulus related
    to interacting with others. My wife retired before me, and I notice her ability to
    talk, make decisions, and stay focused on tasks has diminished significantly.
    Retirement is a death sentence, just a slow one.

  17. How about the scent of Sweet Caporal or rain…these have brought back powerful pleasant memories. I can not say any of the ‘study’ scents do I recall having returned memories to me.

  18. Which particular oil was used?

  19. Given this study was sponsored by P&G this will result in product development from the company. I believe they even mentioned a release is scheduled for the fall.

  20. more info is needed what scent,brand,how to purchase and more proof of trails.

  21. A smelly story for sure

  22. If only one of 8 outcomes for the Rey test was significant, does this mean that the results were only 12 1/2% successful?

  23. Had the OG Covid in 2020 and had loss of smell and taste for 3 months. In March of 2022 I made a sleepy mistake and used white vinegar in my nasal irrigator. The ER had me sit for 2.5 hours while snotting everywhere. I still don’t have my smell back from that. I’ve tried Peppermint, Tea Tree and Eucalyptus oils. Nothing. Any suggestions?

  24. What is up with the creepy AI photo up top?

  25. I would like to know where to purchase the diffuser with the oils. My friend is in beginning stages of Alzheimer’s.

  26. There is an old saying that “If something sounds too good to be true, then it probably isn’t true.” Who among us wouldn’t want to have an improved memory at any age? We are therefore inclined to believe a quick and easy solution. However, there are many questions left unanswered. Humans can become habituated to bad odors and no longer smell them. Is that why they rotated the different essential oils? Might it be that only one or two odors are effective? Did they look for that? They only used 7 oils. What about the other 60? Or ones that they didn’t try? It has long been known that smells associated with strong emotional experiences will infuse a sense of well being. However, that isn’t the same as being able to remember a forgotten computer password, of the name of someone you haven’t seen in a long time who isn’t associated with a particular smell. This doesn’t quite pass the smell test.

  27. what happens if you dont have sense of smell due to nasal allergies?

  28. This article does little to inform, but is high in hype. I would expect this type of writing from Weekly World News or a similar bird cage liner.

  29. Link to the study:

    Quote from the study:
    “Individuals assigned to the olfactory enrichment group were provided with an odorant diffuser (Diffuser World) and 7 essential oil odorants (rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender; from The Essential Oil Company, Portland, OR) in identical glass vials that each fit into the diffuser. They were asked to turn on the diffuser when they went to bed, and the odorant was released into the air during the night for 2 h when they first went to sleep.”

    I hope this helps!

  30. rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender

  31. rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender
    Those are the oils used in the study.

  32. I went to the research article itself. Stated using the defuse for 2 hours per night right at bed time and rotating: rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender; from The Essential Oil Company, Portland, OR

  33. Clifford A Johnson | September 4, 2023 at 8:09 am | Reply

    So- which scent is it?? All that hype,bla bla bla.

  34. It amounts to a P&G ad. While we’re waiting for the magic scent to be revealed, maybe this’ll help somebody: growing a garden can awaken all the senses. Today, I smelled petunias, basil, lemon balm, bee balm, agastache, and butterfly bush. I heard all manner of birdsong, and I listened and watched a cicada stridulate. I saw tadpoles swimming in the wee ponds and had a baby frog jump onto my hand. Gardening can tone and strengthen muscles, expand one’s dose of fresh air, improve balance, and boost one’s vitamin D intake. It doesn’t take but a $1 pot and some seeds, and you will find some healing and help the earth heal as well…while you wait for P&G to figure out a way to monetize your life.

  35. It has been said many times before. “Stop and Smell the Rose’s”. I’m paying attention this time.

  36. Everyone wants to know what the smell is but the article keeps it a secret, so my best guess for one for everyone to try is rosemary oil.
    Rosemary is well known as the herb of remembrance.
    Sniffing freshly crushed rosemary leaves before taking a test for example can help with recall during the test.

  37. All that and no actual list of which scents they were

    • C Michael Brannan | September 4, 2023 at 1:59 pm | Reply

      It would be an observation if people whose career involves use of scents on a daily basis (e.g., cooks or flourists) have a significantly lower rate of dementia or other cognitive decline than the general population.

    • Robert Uomini | May 23, 2024 at 8:29 am | Reply

      The list of scents was given in the research paper: Rose, Orange, Eucalyptus, Peppermint, Rosemary, Lemon and Lavender.

  38. 226% of people who fall for this should save their money.

  39. What was in the diffuser, what was the smell they were getting?


  40. Unfortunately and hopefully I’m wrong but it looks like P&G will monetize this and all oils and diffuser used will suddenly become way more expensive. Such is the world we live in.

  41. Essential oils have been used for centuries. While P & G are going to make a fortune from this, there still might be something to it. But, I think the gardener has the right idea!

  42. Dr. Kerry Meltzer | September 5, 2023 at 6:00 am | Reply

    P&G produces the top three laundry brands containing the most toxic chemical fragrances (Tide, Gain, Bounce). These products cause mental impairment, asthma and worse. (Check EWG’s website ranking). If they would only use a hint of actual, natural EOs instead, the world would be a better place. Unfortunately I think they have something else up their sleeves.

  43. To those who have read this article, you need to go to the address that Munirih provided and read the study. It’s written in an easy to read format. The info. provided in this study will blow you away, with the scary seriousness that olfactory loss (that loss of smell) causes. It appears this has been known for quite awhile. There does appear to be encouragement from olfactory stimulation from odors (although inhaled OIL odorants may have some risk, depending on the type of oil used, because certain oils can deposit in the lung alveoli and can’t be broken down by the body, resulting in a potential chemical emphysema. Talk to your doctor about this – preferably a pulmonologist – lung doctor) that the study speaks about. You really need to read this study for yourself and share it. Don’t ignore it.
    Concernedfdb 9-5-23

  44. The http address that I listed, from Munirih, was removed form my original posted note. Go to the 3rd, or last address that Munirih listed and look it up and read it.
    Concernedfdb 9-5-23

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