Guaiacwood: a thick oil with the scent of rose and smoke from an endangered tree

In brief: Guaiacwood oil (Bulnesia sarmientoi) is a thick, almost solid oil with a sweet, rosy-woody and smoky scent. It suits mainly an oil burner and as a fixative in natural perfumes, on the skin diluted to 1–2%. The tree is endangered and protected by the CITES convention, so origin matters.

Guaiacwood is rather a rarity in aromatherapy, but in perfumery it is a classic. Its oil smells like something between rose, wood and a faintly smoked tea, and in a perfume it lasts for hours. When you open the bottle for the first time, you may be surprised that nothing flows out of it: the oil is so thick that it solidifies in the cold.

In this article you will find how to handle such an oil, what it suits and why, with guaiacwood more than with other oils, it matters where it comes from.

Guaiacwood or palo santo? Beware of the name

The guaiacwood tree in Paraguay and Argentina is also called "palo santo", like the Ecuadorian Bursera graveolens. These are, however, two unrelated trees with a different scent. Our BIO guaiacwood oil is Bulnesia sarmientoi from Paraguay. We sell the oil from Bursera graveolens as BIO Palo Santo. Always look for the Latin name on the label; "palo santo" alone is not enough.

An endangered tree: what it means for the oil

Bulnesia sarmientoi grows in the Gran Chaco region on the borders of Paraguay, Argentina and Bolivia. Since 2010 it has been in Appendix II of the CITES convention, so international trade in its wood and products is subject to permits. The IUCN Red List placed it among endangered species in 2018 because of deforestation of the Gran Chaco and great demand for wood, extracts and oil.

According to researchers from the University of Nice, the oil is distilled from the heartwood as a by-product of the timber industry, that is, from sawdust and offcuts. That does not automatically mean the harvesting is sustainable, however. For you this gives a simple rule: buy guaiacwood only with the Latin name and country of origin stated, from a seller who knows the supplier, and do not use up the oil needlessly by the dozen drops. Very little of it is enough for scent.

How to work with a thick oil

Guaiacwood oil is semi-solid at room temperature, caramel to pale amber. On its own it is not suited to an ultrasonic diffuser, because it would clog the membrane and does not form a fine mist on water. Proceed like this:

1. Immerse the bottle for a few minutes in a mug of warm (not hot) water, or hold it in the palm of your hand; the oil will thin.
2. If you want the oil in a blend, drip it straight into an empty bottle with thinner oils, for example orange or lavender. In a blend it stays liquid.
3. In an oil burner you can use it even on its own: 1–2 drops per dish of water; the warmth dissolves it.
4. For a diffuser use only a ready blend in which guaiacwood makes up at most a quarter, and wipe out the tank after use.

Scent and blends

The scent is sweet, creamy and balsamic with a rosy note that is compared in perfumery to a tea rose. The smoky undertone is delicate in a good oil. The perfumer Steffen Arctander describes that a markedly "smoked" scent recalling ham tends to be a defect from overly aggressive distillation. Guaiacwood is a base note; it lasts long and slows the fading of lighter scents. It goes with:

• rose and geranium – they emphasise its rosy note,
• orange and bergamot – they lighten it,
• frankincense and Himalayan cedar – a deep woody composition.

Recipes

• Evening oil burner: 1 drop of guaiacwood, 2 drops of frankincense.
• Rosewood (oil burner): 1 drop of guaiacwood, 3 drops of rose.
• Orange salon (blend for the diffuser): in a bottle mix 5 drops of guaiacwood, 10 drops of orange and 5 drops of cedar; for the diffuser use 3–4 drops of the blend.
• Oil perfume 10 ml: into 10 ml of jojoba put 1 drop of guaiacwood, 1 drop of rose and 2 drops of orange (2%). Apply to the wrists and behind the ears. Do not put bergamot in here; it is phototoxic on skin exposed to the sun.

Detailed dosing for the diffuser and oil burner by room size is in the article how many drops for a diffuser and oil burner, and the principles of composing scents in the article how to combine essential oils.

On the skin and in cosmetics

For guaiacwood oil, Tisserand and Young state no special restrictions or dermal maximum. Even so, use it diluted on the skin: 1% for the face (2 drops per 10 ml, 6 drops per 30 ml), 2% for the body (4 drops per 10 ml, 12 drops per 30 ml). For a bath, add it only dissolved in a spoonful of carrier oil. General principles can be found in the article essential oils for the complexion.

Thanks to its sesquiterpene alcohols (bulnesol, guaiol), the oil is stable and lasts several years. Store it closed in the cool and dark; thickening in the cold is not a defect.

Tradition and research

Guaiacwood is very hard and is traded as "Paraguayan lignum vitae". The oil is used mainly in perfumery and in soaps. There are no reliable studies on health effects, and manufacturers sometimes mention azulene, but it is not documented in the oil in any significant amount naturally. Take it as a scent, not as a product for the skin or against pain, and never swallow it.

What to watch out for

• Pregnancy and breastfeeding: the product page recommends avoiding guaiacwood during this period. Keep to that, even though Tisserand and Young state no special contraindication.
• Children: not under 2 years. For older children 1 drop in a blend in an oil burner is enough, and on the skin only dilution according to age (2–6 years 0.5–1%, from 6 years up to 1%). More in the article essential oils and children.
• Cats and dogs: do not apply the oil to animals, and do not run an oil burner in a room the cat cannot leave. See essential oils and pets.
• Open flame: do not heat the oil on a hob or over a candle directly in the bottle, only in a water bath.

Frequently asked questions

Why is guaiacwood oil solid?

It contains a lot of sesquiterpene alcohols, which crystallise at room temperature. It is enough to warm the bottle in the palm of your hand or in warm water; the oil thins and its properties do not change.

Can I put guaiacwood in a diffuser?

Not on its own; it would clog an ultrasonic diffuser. Use an oil burner, or mix it beforehand with thinner oils, where it makes up at most a quarter of the blend.

Is guaiacwood the same as palo santo?

It is sometimes called that colloquially, but botanically it is a different tree from the Palo Santo of Ecuador (Bursera graveolens). They differ in scent and in protection; guaiacwood is protected by the CITES convention.

What does guaiacwood smell like?

Sweet, creamy and woody, with a rosy note and a delicately smoky undertone. In perfumes it is used as a long-lasting base.

Recommended products

• BIO Guaiacwood, essential oil 10 ml – Bulnesia sarmientoi from Paraguay, a rosy-woody base scent.
• BIO Rose, essential oil 10 ml – with guaiacwood it makes an elegant "rosewood".
• BIO Orange, essential oil 10 ml – a thin citrus in which guaiacwood dissolves well.
• BIO Jojoba 10 ml – a carrier for an oil perfume.
• Ceramic oil burner 9 × 7.5 cm – a better choice than an ultrasonic diffuser for thick guaiacwood.

Sources

• Tissandié L. et al.: Towards a complete characterisation of guaiacwood oil, Phytochemistry 2018 – PubMed
• AromaWeb: Guaiacwood Essential Oil, composition, consistency and IUCN threat status – aromaweb.com
• Tisserand R., Young R.: Essential Oil Safety, 2nd edition, Churchill Livingstone 2014 (Guaiacwood profile, pp. 298–299).
• CITES: Appendices I, II and III (Bulnesia sarmientoi, Appendix II) – cites.org

Updated: 27 September 2026