“Nicotine-free” is a fact. “Completely safe” would be a promise.
Nobody in this category can make that promise yet. Including us. Here's what we can tell you, what our lab test covered, and what's still unknown.
Short answer
Flavoured air avoids the biggest known harms of smoking and vaping: nothing is burned or heated, and there's no nicotine. But nicotine-free isn't the same as proven safe. Breathing small amounts of essential oils every day has barely been studied. An independent lab analysed the air drawn through a Lio and confirmed nothing burns or heats up; it did not assess health effects.
What we know for sure
Most of the harm from smoking comes from burning tobacco. Most of the open questions about vaping come from heating a liquid and breathing in the result.
Flavoured air does neither. A Lio has no battery, no coil, no heating element. Air passes over a fibre core at room temperature, and that's it.1
Much of the research on inhaled flavourings is about heated e-liquids. A 2022 review found clear evidence of harm from diacetyl and cinnamaldehyde in e-liquids, and too little data on most other flavours.4 Air drawn over an unheated core is a different and much smaller exposure. It has also been studied far less.
What our lab test covered
We asked an independent laboratory to analyse the air you actually breathe through a Lio. Here's what they did:
- Simulated about four days of normal use with a Minty Magic core.
- Analysed the air drawn through the device with gas chromatography mass spectrometry, a standard way to identify what's in air.
- Found the compounds you'd expect from mint oil: natural essential-oil and botanical constituents carried in the airstream.
- Confirmed how Lio works: no combustion, no heating, no smoke, no vapour.
And here's what the lab did not do: it did not assess health effects, and it did not say Lio is safe. We won't say it either.
What nobody can tell you yet
- Long-term human data. There isn't any, for Lio or any other flavoured air device.
- Every flavour. Our test covered Minty Magic.
- How you personally react. People respond differently to essential oils, the same way they do to foods or cosmetics.5
What independent experts say
In 2022, researchers writing in Toxicological Sciences flagged inhaled essential oil devices like Füm and Monq as a new category worth watching. They pointed out that manufacturing isn't strictly regulated, and that the known benefits of aromatherapy come from very low doses, like room diffusers.2
McGill University's Office for Science and Society looked at Füm and reported an estimate of less than a microlitre of essential oil per draw. Their verdict: not necessarily unsafe, but not proven risk-free either.3
Who should check first
- Pregnant or breastfeeding, asthma, on medication, or a known allergy? Ask your doctor first.6
- If anything irritates, stop.
- Lio is for adults only.
- Cores aren't food. Keep them away from children and pets; swallowing essential oils can make people ill.2
What we're doing about the unknowns
Keeping ingredient lists short, so there's less to wonder about. Updating this page, with the date at the top, whenever new research comes out.
Remember this
Frequently asked questions
Is it safe to inhale essential oils?
Low doses, such as from room diffusers, are common. Regular inhalation through a device has not been well studied, and people react differently. Stop if anything irritates.
Is flavoured air safer than vaping?
Flavoured air heats nothing and contains no nicotine, which removes the main concerns about vaping. That doesn't make it proven safe, and no long term studies exist yet.
Can you get lipoid pneumonia from flavoured air?
That risk is discussed for oil based diffusers and nebulisers. It hasn't been reported for unheated flavoured air devices, but research on them is limited.
Sources
- Lio. Science and safety. breathelio.com
- Tackett AP, Rebuli ME. Alternative flavored inhalable products: a new respiratory hazard? Toxicological Sciences. 2022;187(1):1 to 2. pmc.ncbi.nlm.nih.gov
- McGill University Office for Science and Society. Are Füm's essential oils safe to inhale? www.mcgill.ca
- Review of 38 reports on flavoured e-liquids and the respiratory system, 2006 to 2021. PubMed Central PMC9590402. pmc.ncbi.nlm.nih.gov
- American Lung Association. Essential oils: harmful or helpful? www.lung.org
- Lio. Ingredients, flavour by flavour. breathelio.com
Founder of Lio. Writes about habits and the products Lio makes. Has a commercial interest in this topic, which is why every claim here is sourced.
Lio is not a medical device, a smoking cessation aid or a treatment, and makes no health claims. This guide is general information, not medical advice. If you want help with nicotine dependence, speak to a pharmacist, GP or your national quit service.
