Room fragrance and relaxation: what scents really do

What a scent does in your head

Smell is a very direct sense. Signals from the nose travel with few detours into brain regions involved in emotion and memory.

For relaxation, this link matters more than any single ingredient. A scent you notice every time you wind down gradually becomes a signal in its own right that the working day is over. That works with lavender just as well as with vanilla or lemongrass. It only works, though, if you like the scent. A smell you find intrusive will not relax you, whatever has been written about it.

A second effect is often overlooked: your nose adapts. After a few minutes in the same room you perceive a scent far more weakly, even though just as much of it is still in the air. Topping up at that point means overdosing. Check the strength when you come back into the room from outside.

What studies show and what they do not

The most thorough analysis of lavender comes from Italy. The authors screened 65 randomised trials with almost 8,000 participants, plus 25 further studies without random allocation. Inhaling lavender lowered momentary anxiety by around six points on average, on a common scale that runs from 20 to 80. The scent had no measurable effect on blood pressure.

The authors clearly qualify their own result. Most trials carried a high risk of bias, and their designs varied widely. For inhalation they therefore speak only of an indication of an effect. The finding was clearer for lavender oil in capsules, taken as a medicine for at least six weeks. That is something different from a scent in the living room. Massages with lavender oil also lowered anxiety scores. Whether that was down to the lavender or to the massage itself could not be separated from the data.

Seen more broadly, the picture is more sober. An overview of ten systematic reviews on aromatherapy found work on high blood pressure, depression, anxiety, pain and dementia. Most were methodologically weak, and in none of these areas did the authors consider the evidence convincing. A Cochrane review on people living with dementia reached a similar conclusion in 2020: across 13 trials with 708 participants, eight of them using lavender, there was no convincing benefit. Sleep and mood showed no advantage either, though based on no more than two trials per question.

For vanilla or woody notes, which are common in living rooms, there is no comparable body of research. Anyone buying a room fragrance is therefore buying atmosphere. That is a good reason, as long as nobody promises more.

Which scents suit the evening

The studies do not support a ranking. Practice does suggest a rough order:

• Lavender: the best studied scent for calm, herbal and lightly floral.
• Warm, soft notes such as vanilla: popular in the living room and in winter. Proof of an effect is missing, yet many people find them cosy.
• Fresh notes such as lemon or lemongrass: better suited to the daytime. Many find them invigorating; late in the evening they fit less well.

The NAIPO fragrance range follows the same logic. It was developed over two years from the feedback of more than 5,000 guests who choose a scent before their appointment in the Relax Lounge. Vital Essence with lemongrass is meant for the day, Calm Essence for the evening, Golden Comfort with vanilla as a warm scent for the living room. We promise no effect on stress or sleep for any of them. The scents currently available are shown in the room fragrance collection.

Diffuser, reed sticks or spray

• Reed sticks (reed diffuser): rattan reeds draw the fragrance oil up from the bottle and release it evenly. No power, no water, hardly any upkeep. The scent gets stronger when you turn the reeds over or add more of them. Vital Essence comes in this form, with 200 ml and eight rattan reeds.
• Room spray: works instantly and only briefly. Good for scenting a room before the evening without the fragrance lingering all day. Golden Comfort comes as a set of a 200 ml room spray and a 100 ml diffuser.
• Electric diffuser: disperses essential oil with water as a fine mist, often on a timer. This is the easiest way to control strength. The water tank has to be cleaned regularly, however, otherwise germs can multiply.
• Scented candles and incense: atmospheric, but they release smoke and fine particles. In small rooms and for sensitive airways they are the poorer choice.

For the bedroom: use little, and before bedtime rather than all night. A diffuser on a timer or a single spray half an hour beforehand is enough. What else makes a calm evening ritual is covered in Massage before bed. Warmth intensifies any scent. If you combine scent with warm towels, the right dosage is explained in Scented oshibori: what works.

Safety: when scent is a bad idea

Essential oils are concentrated plant substances. A systematic review of case reports found 71 people with adverse effects, ranging from mild to severe. The most common was skin inflammation, and lavender was among the oils most often involved. How often such reactions occur overall is unknown. A few rules follow from this:

• Never neat on the skin: essential oils belong heavily diluted in a carrier oil, or not on the skin at all. Fragrance oil from a diffuser is not made for skin.
• Asthma and sensitive airways: strong scents can trigger symptoms. Try a new scent carefully, ventilate well, and stop entirely if symptoms appear.
• Pets: cats are considered particularly sensitive because they break down some components of essential oils poorly. Dogs and birds react to scent too. Keep diffusers out of reach, leave your animal a room without fragrance, and if in doubt ask your vet.
• Pregnancy, breastfeeding and young children: the data here are thin. Talk to your doctor or midwife before use. Keep fragrance oil out of reach of children, because it can be dangerous if swallowed.

See a doctor if a rash, shortness of breath or wheezing appears after contact with a scent. If a child has drunk fragrance oil, call a poison control centre straight away. And if stress, anxiety or sleep problems persist for weeks, have them checked by a doctor. A room fragrance is no substitute for treatment.

Frequently asked questions

Does lavender help you fall asleep?

That is not reliably proven. Lavender studies mainly measure anxiety and tension, and even there their quality is mostly low. As a fixed ritual before sleep, a subtle scent can help you switch off. Do not leave a diffuser running all night, though.

Are natural essential oils safer than synthetic fragrances?

Not automatically. Natural oils can irritate the skin and trigger allergies as well. What matters is dosage, ventilation and how well you personally tolerate them.

How strong should a room fragrance be?

Faint enough that you notice it on entering the room and barely at all a few minutes later. If you can clearly smell it the whole time, there is too much. With reed sticks, fewer reeds help; with an electric diffuser, a shorter running time.

Sources

• Donelli D, Antonelli M, Bellinazzi C, Gensini GF, Firenzuoli F (2019): Effects of lavender on anxiety: a systematic review and meta-analysis. Phytomedicine. doi:10.1016/j.phymed.2019.153099
• Lee MS, Choi J, Posadzki P, Ernst E (2012): Aromatherapy for health care: an overview of systematic reviews. Maturitas. doi:10.1016/j.maturitas.2011.12.018
• Ball EL, Owen-Booth B, Gray A et al. (2020): Aromatherapy for dementia. Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD003150.pub3
• Posadzki P, Alotaibi A, Ernst E (2012): Adverse effects of aromatherapy: a systematic review of case reports and case series. International Journal of Risk and Safety in Medicine. doi:10.3233/JRS-2012-0568

This article is no substitute for medical advice.