A guest asks for "something with lemon in it" before a day on the water, and mentions in passing that she is fourteen weeks pregnant. Two decisions have just been made for you, and both of them are about safety, not scent. Essential oils are the part of spa work most casually handled and most capable of causing real harm.
Carrier oils
Essential oils are never applied neat. They are diluted into a carrier — a plain vegetable oil that provides slip and delivers the blend.
| Carrier | Character | Notes |
|---|---|---|
| Grapeseed | Light, low odour, absorbs well | The reliable default onboard |
| Sweet almond | Medium weight, good slip | Nut allergy risk — always ask |
| Fractionated coconut | Very light, long shelf life, washes out | Excellent for yacht linens |
| Jojoba | Technically a wax, close to skin sebum | Good for facials; expensive |
| Wheatgerm | Heavy, vitamin E rich | Contains gluten proteins — avoid |
Buy small, store cool and dark, and rotate stock — oils go rancid, and rancid oil smells like an amateur.
Dilution
| Use | Dilution | Roughly |
|---|---|---|
| Full body massage, healthy adult | 2% | 12 drops per 30 ml carrier |
| Face | 1% | 6 drops per 30 ml |
| Pregnancy (2nd/3rd trimester, if trained) | 1% max | 6 drops per 30 ml |
| Children, elderly, sensitive skin | 0.5–1% | 3–6 drops per 30 ml |
If in doubt, go weaker. Nobody has ever complained that a massage was insufficiently fragrant.
The safety rules that matter
- Photosensitivity. Citrus oils, above all bergamot, and also lemon, lime, grapefruit and orange, can cause severe phototoxic burns on sun-exposed skin. On a yacht this is the single most likely oil injury. Do not use citrus oils on skin that will see the sun within 12–18 hours. Use furocoumarin-free (FCF) bergamot if you must.
- Pregnancy. Do not blend for pregnant guests unless you hold pregnancy massage training. Avoid clary sage, rosemary, juniper, fennel, basil and jasmine. When unsure, use a plain unscented carrier oil — it is a perfectly good massage.
- Allergies. Ask about nut allergies before choosing a carrier, and about fragrance and plant allergies before blending. Patch test any new product 24 hours ahead where possible.
- Epilepsy. Avoid rosemary, fennel, sage and camphor-rich oils.
- High blood pressure, anticoagulants, cancer, children under 5: default to a plain carrier and refer any doubt to a doctor.
- Never let a guest ingest essential oils, and never advise them to. That is not your scope, in any country.
- Keep oils away from eyes, and keep an unscented carrier oil to hand as the dilutant if oil gets somewhere it should not.
Onboard Notes
- Neat essential oil never touches a guest.
- Citrus plus sun equals burns — the classic yacht mistake.
- Nut allergy question before the almond oil comes out, every time.
- Pregnant, unwell, medicated or unsure? Plain carrier oil, and a lovely massage anyway.
- Preparatory study only. Nothing here qualifies you to treat. Massage requires an accredited vocational qualification (for example ITEC, CIBTAC or VTCT) and professional insurance.