If your fragrance oil smells of lavender, bergamot, neroli, coriander or "fresh linen", its safety data sheet almost certainly lists linalool. It's one of the most used molecules in perfumery, and one of the most common names in a candle's allergen line. Here's what it smells like, why its allergy story is really about oxidation, and how its EU classification plays out in a candle at a normal fragrance load.

One molecule, two smells

Linalool (CAS 78-70-6, EC 201-134-4) is a small terpene alcohol with a fresh, floral, slightly woody smell. It's chiral: it exists as two mirror-image forms, and your nose can tell them apart.

(R)-(−)-linalool, also called licareol, is the woodier, more lavender-like form. It's the one in lavender, rose, neroli and sweet basil.
(S)-(+)-linalool, or coriandrol, is sweeter and more citrus-floral. It dominates coriander seed oil and sweet orange.

A sensory study in Chemical Senses (Sugawara et al., 2000) found that people perceive and respond to the two forms differently. Synthetic linalool is usually close to a 50:50 mix of both.

Natural sources can be rich in it. The ISO specification for coriander seed oil (ISO 3516) sets linalool at 65 to 78%, and lavender oil typically contains a quarter or more. Bergamot, ho wood and rosewood are other big natural sources. So "all natural" doesn't mean linalool-free, and an essential oil can deliver more linalool than a synthetic fragrance oil.

Fresh linalool barely sensitises. Oxidised linalool does.

Linalool has a double bond that reacts slowly with oxygen in the air. The first products are hydroperoxides, and they're the real allergens:

Swedish researchers showed that high-purity linalool gave no reactions in guinea pig sensitisation tests, while linalool left exposed to air for 10 weeks did (Sköld et al., Contact Dermatitis, 2002).
A follow-up study identified the hydroperoxides and found them to be the strongest sensitisers among the oxidation products, while pure linalool showed no sensitising potential in the local lymph node assay (Sköld et al., Chemical Research in Toxicology, 2004).
In people, oxidised linalool is a common allergen. An international study patch-tested 2,900 consecutive dermatitis patients in six countries and found 6.9% reacted to it (Bråred Christensson et al., Contact Dermatitis, 2012).

This is why the fragrance industry's own standard focuses on freshness. The IFRA Standard for linalool says it should only be used with peroxides kept to the lowest practical level, for example by adding an antioxidant such as 0.1% BHT or alpha-tocopherol at production, and it sets a peroxide value below 20 millimoles per litre.

What ECHA records for linalool

We checked ECHA's database on 29 September 2026:

Harmonised classification (index 603-235-00-2, added by the 10th adaptation to technical progress): Skin Sens. 1B, H317 "May cause an allergic skin reaction", exclamation mark pictogram, signal word "Warning". No specific concentration limit, so the generic limits apply.
Self-classifications: industry has notified 20 variants. The REACH registrants' joint entry, covering over half of all notifications, adds Skin Irrit. 2 (H315) and Eye Irrit. 2 (H319) to Skin Sens. 1B. A minority of notifiers also add STOT SE 3 (H335).

The harmonised Skin Sens. 1B is the one that matters for a candle label. Linalool is also one of the fragrance allergens named in EU cosmetics law, and it stays on the longer allergen list from Regulation 2023/1545. But a candle isn't a cosmetic, so its label follows CLP thresholds, not the much lower cosmetic ones.

The thresholds that apply in your candle

For a Skin Sens. 1B substance with no specific limit, CLP checks its concentration in the finished candle:

1% or more: the candle is classified H317, with the exclamation mark and "Warning".
0.1% to under 1%: no pictogram, but the label needs the EUH208 line, "Contains linalool. May produce an allergic reaction."
Under 0.1%: nothing on the label for linalool.

The irritation classes rarely matter. Skin Irrit. 2 and Eye Irrit. 2 only classify a mixture from 10% of such ingredients combined, and at a 10% load your whole fragrance is only 10% of the candle.

A worked example: a lavender candle

Take a hypothetical lavender fragrance oil whose SDS lists 20% linalool. The linalool in the candle is simply that 20% times your load:

10% load: 2.0% linalool. Over 1%, so the candle gets H317, the exclamation mark and "Warning".
5% load: 1.0% linalool. Exactly on the line, and the limit is "1% or more", so H317 still applies.
4% load: 0.8% linalool. The pictogram goes, and linalool moves to the EUH208 "Contains linalool" line.

Now swap in pure coriander seed oil at 10%. With around 70% linalool it puts about 7% linalool in the candle, seven times the H317 limit. A fragrance with just 1% linalool, by contrast, gives 0.1% at a 10% load and already needs the EUH208 line. That's why linalool shows up on so many candle labels, and why the load you choose often decides between a pictogram and a one-line mention. Real fragrances contain other sensitisers too, each checked against its own limit, as we explain in our guide to candle hazard pictograms.

Keep your linalool fresh

The label is calculated from the SDS composition, so oxidation won't change it. It can change how allergenic your product really is. A few habits help:

Buy from suppliers who stabilise. Ask whether linalool-rich oils contain an antioxidant and whether they meet the IFRA peroxide specification.
Store cool, dark and closed. Heat, light and air all speed up oxidation. Keep caps tight and don't leave oil standing in an open pouring jug.
Limit headspace. Decant a half-empty large bottle into smaller full ones.
Use it within its shelf life. Buy quantities you'll use, and date bottles when you open them.

Molekule reads the linalool percentage from your fragrance's SDS, checks it against ECHA's live classification and works out, for your candle and load, whether you need H317, an EUH208 line or nothing. Check your linalool-rich fragrances in Molekule.

Linalool in candles: scent, oxidation and the CLP label