I want to start this post with a confession.
Before I started making candles, I burned conventional scented candles at home regularly. I loved them. I never once questioned what was in them or whether they were affecting my health. Even when I started noticing the headaches, nausea, dizziness and breathing issues, I put it down to other things.
Then I started making candles professionally and everything changed.
Within months of working with conventional fragrance ingredients, I became seriously unwell. I was eventually diagnosed with severe lung inflammation (chemical pneumonia) that lasted for months. As someone already living with asthma, allergic asthma and chemical sensitivities, this was a serious wake-up call. I spent a lot of time in and out of doctors’ appointments and hospital visits, underwent multiple rounds of antibiotics as a ‘just in case it should turn bacterial and faced the very real possibility that I might have to give up on my business and the very thing I loved doing most.
I'm sharing this not for sympathy but because it's the entire reason, I can answer the question "are candles bad for you?" honestly and from a place of genuine, hard-won experience. I spent the better part of a year researching candle ingredients in what some would call forensic detail 😊 because I had no choice. And what I found changed how I make candles and the trajectory of my business for the better.
So here is my honest answer.
Do scented candles cause headaches?
If you've ever lit a scented candle and found yourself with a headache within the hour, you are absolutely not not alone.
The reason this happens comes down to two main factors: the wax and the fragrance.
Many mass-produced candles are made with paraffin wax which is a petroleum-derived by-product. When paraffin burns it can release volatile organic compounds including benzene and toluene into the air. These are known irritants that can affect the respiratory system and nervous system, and in sensitive individuals can trigger headaches within minutes of lighting a candle.
The fragrance is often the bigger culprit though. Many conventional fragrance oils contain phthalates. These are chemical compounds used as a quick fix to help scent throw further and faster. When burned, phthalates are released into the air where they can be inhaled. Research has linked phthalate exposure to headaches, respiratory symptoms and hormonal disruption.
Overly strong scents like those made with cheap fragrance oils and surplus additives, can overstimulate the olfactory system and in migraine sufferers can activate the trigeminal nerve, which is directly linked to headaches.
My take as a candle maker: I've always been reactive to traditional fragrance (very strong perfumes, air fresheners, heavily scented products.) When I started developing headaches and respiratory symptoms in my studio,I started tracking which ingredients I was working with that day. The correlation was clear and it drove my entire decision to reformulate. I now make candles that I can burn in my own home without symptoms. That's the standard I hold myself to.
Can scented candles cause breathing problems and trigger asthma?
This is something I feel very strongly about and want to address honestly.
The short answer is yes! for people with asthma, the wrong candle can absolutely trigger or worsen symptoms.
The American College of Allergy, Asthma and Immunology advises people with asthma to consider avoiding scented candles and air fresheners altogether. That's a significant position from a major medical body and it reflects the reality that for sensitive airways, fragrance chemicals act as direct irritants - narrowing airways, increasing mucus production and causing breathing difficulty.
Research has found that roughly a third of people with asthma have chemical hypersensitivity, and more than a third report irritation from scented products specifically.
The VOCs released from paraffin candles, including benzene and toluene are particularly problematic for sensitive airways. Phthalates in fragrance oils can also enter the bloodstream through inhalation and have been shown to exacerbate asthma symptoms and allergic responses.
My personal experience: I have asthma and in particular allergic asthma meaning my asthma is triggered by allergens and chemical sensitivities rather than just physical exertion. Before I reformulated my candles, I was experiencing respiratory flare-ups, headaches and sometimes dizziness when working with certain fragrance ingredients. At my worst I developed severe lung inflammation that required months of recovery, multiple doctor visits and antibiotics. Part of my recovery involved removing every conventional fragranced product from my home and studio and starting completely from scratch with ingredients I had researched and verified myself. It was slow, frustrating and at times disheartening but it worked. And it completely changed the way I approach candle making.
Understanding fragrance sensitivities - why some people react to candles and others don't!
Something that puzzled me for a long time was why some people seem completely unaffected by conventional candles while others like me react quite strongly.
The answer lies in something called chemical sensitivity, and it exists on a spectrum.
For most people, occasional exposure to conventional candle chemicals at the levels typically involved in burning one candle at home doesn't cause noticeable symptoms. Their bodies process the irritants without obvious reaction.
For people with asthma (in particular allergic asthma), allergies, chronic sinusitis or multiple chemical sensitivities, the picture is very different. Their airways are already more reactive and less resilient to irritant exposure. What registers as background noise to someone without sensitivities can trigger a significant response in someone whose system is already on high alert.
It's also worth understanding that candle sensitivity isn't always a true allergy in the clinical sense. A genuine allergy involves the immune system identifying a substance as a threat and releasing histamine. What most people experience with candles is actually a direct chemical irritation of the nasal passages and airways, which produces very similar symptoms but through a different mechanism. This distinction matters because antihistamines, which are designed to block histamine, often provide little relief for candle-triggered symptoms for exactly this reason.
My take: I think a lot of people who are sensitive to fragrance and candles have simply normalised their symptoms without ever connecting them to what they're burning at home. Headaches that appear after a relaxing evening in. Stuffiness that seems like a cold but clears quickly. A vague sense of nausea after burning a particularly strong candle. These things are easy to dismiss or attribute to something else. I know because I did exactly that for years before I started making candles and had no choice but to pay attention.
Why do some candles cause nausea?
Nausea from candles is less talked about than headaches but it's genuinely something people experience and I've also experienced it myself.
The mechanism is similar to headache triggering but tends to happen with particularly heavy, sweet or overpowering scents in enclosed or poorly ventilated spaces. Very strong fragrance concentration can overwhelm the olfactory system and trigger a physical response that includes nausea and dizziness. This is particularly common with heavily sweet or musky scent profiles and in people who are already sensitive to fragrance.
VOCs from paraffin wax burning at high levels in a small unventilated space can also contribute to this. In the same way that you might feel unwell sitting in a room with fresh paint, concentrated chemical compounds in the air can cause nausea in sensitive individuals.
My take: This was actually one of my own symptoms when working with certain fragrance ingredients all day. Once I identified which compounds were causing it and removed them from my formulations completely it stopped. The experience made me very deliberate about fragrance concentration in my own candles - I want a beautiful scent throw but I never want anyone to feel unwell after burning one of my candles.
What I now do differently as a candlemaker and why
After months of research, lived experience and working through Safety Data Sheets, European Chemicals Agency documentation and hundreds of pages of chemical classification guidelines, I arrived at a set of non-negotiables for every candle I make.
Every fragrance oil I choose must be classified free from:
• Phthalates - linked to headaches, respiratory symptoms and hormone disruption.
• CMR substances - carcinogens, mutagens and reprotoxins.
• Parabens and silicones - questioned for their effects on hormonal health
• PEG and acrylates - additional chemical compounds I researched and chose to eliminate
• Hormone Disruptors – chemicals that can interfere with the body's endocrine system.
• Additives - a broader category covering dyes, stabilisers and other compounds sometimes added to fragrance oils or waxes to improve colour, appearance or performance.
I use 100% natural and biodegradable soy wax rather than paraffin - it burns more cleanly, produces less soot and has been the better choice for my own respiratory health working with it every day.
I also want to be transparent about something: reformulating without certain conventional fragrance ingredients is genuinely a lot harder. Many of the ingredients I avoid are used precisely because they create a strong scent throw. Working without them means I have had to adapt and honestly why it took me so long to finally launch my business it meant testing a lot more (many of the fragrances just didn’t work as well and didn’t meet my standards for scent throw and so had to be eliminated after testing) formulating more carefully to ensure that the heat and depth of my melt pool is able to disperse the scent to achieve a good scent throw without overpowering a space and I think that's the right trade-off. A beautifully scented space that doesn’t overwhelm and also a bonus is that I have been told on many occasions that my candles smell way less artificial and have a more true to life scent experience. I've had so many customers tell me my candles are the first ones they've been able to burn without a headache, nausea or asthma symptoms and that feedback honestly means everything to me.
Practical candle care tips and things you can do, that make a real difference.
Whether you burn my candles or anyone else's, these simple habits can make a genuine difference especially if you have asthma or sensitivities:
Trim your wick to around 4mm before every burn. A longer wick creates a larger, less controlled flame which produces more soot. A trimmed wick burns cleaner and more evenly.
Burn in a ventilated space. Opening a window slightly even just a crack, allows the air to circulate and disperses any compounds released during burning without putting the candle in a direct draught.
Use a candle snuffer rather than blowing out. Blowing out a candle creates a puff of smoke and soot as the flame extinguishes. A snuffer cuts off the oxygen supply cleanly and avoids that final burst of particles.
Don't burn for more than 4 hours at a time. This is general safety guidance to prevent the flame from becoming too big and too hot, but it can also mean that the fragrance particles and combustion compounds build up way faster and become more concentrated, especially in a smaller space. Giving your space a chance to ventilate between burns makes a real difference to air quality.
Choose candles with ingredient transparency. If a brand is proud of what's in their fragrance oils they will tell you. If they list only "fragrance" with no further information, it's worth asking what that means. Please also be aware of greenwashing and do as much research as you can in to the ethics of the brand and their ingredients if you can.
My honest bottom line
Candles are not inherently bad for you but the ingredients matter enormously, and people with asthma, allergies or fragrance sensitivities deserve to know that the candle they're choosing to burn in their home has been made with that in mind.
I didn't start The Scented Essence Candle Co. because I think candles are dangerous. However, through lived experience and a massive amount of research and passion, it’s evolved into something beautiful that means cleaner scented candles are within reach.
I believe everyone should be able to have a beautiful, genuinely fragrant candle in your home without it affecting your health. That belief came directly from my own experiences, and it drives every ingredient and business decision that I make.
If you want to read more about my personal journey as a candlemaker, then you can read more about it here.
And if you're looking for beautiful scented candles, made with genuinely clean ingredients that you can burn with confidence, even with sensitivities then you can explore our full non toxic candle collection here
