Blending Calendula Oil With Essential Oils: A Dilution Guide

Blending essential oils into calendula oil is a dilution problem first and a scent problem second. Calendula oil is an infused oil, a plant extract in a carrier, so it dilutes the essential oil rather than competing with it, and the safety question is the percentage of essential oil in the finished bottle. We make one oil and do not sell blends, so this article gives you the published dilution ranges and the arithmetic, and no list of "15 combinations", because we found no source showing that any particular combination does anything.

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Decide first whether to blend at all

Skip the blend if the person it is for is any of these: a baby, a pregnant or breastfeeding person, someone with eczema or broken skin (see the NAHA point below), someone allergic to daisy-family plants, or a household with cats. Each has its own reason, drawn from the sources below. For those people, plain calendula oil, a patch test and a conversation with a professional (pediatrician, OB/GYN or midwife, dermatologist, allergist, veterinarian) comes before any essential oil.

The numbers: what dilution for what use

The Tisserand Institute's dilution ranges for adults are: sensitive or impaired skin 0.2-1%, facial products 0.5-1.2%, body oils and lotions 1-3%, bath and wash products 2-4%, and short-term targeted uses 2-10% (Tisserand Institute, Dilution for essential oils). It advises starting low and increasing only if needed, and notes some oils carry specific limits, for example lemon at a 2% maximum for phototoxicity and clove bud at 0.5%. The aromatherapy trade association NAHA says most blends fall between 1% and 5% (NAHA, Safety). Those sources overlap but do not agree at the top: the Institute's age chart lists 2.5-5% for ages 15 and over, higher than its 1-3% body-oil range; they are different Tisserand Institute publications. When sources differ, use the lower figure.

Here is that arithmetic for a 30 mL (about 1 fl oz) bottle, using the percentages directly (volume of essential oil = bottle volume x percentage):

DilutionEssential oil in 30 mLTisserand range it sits in
0.5%0.15 mLSensitive skin up to face
1%0.3 mLTop of sensitive range; face; low body
2%0.6 mLBody oils (also the lemon maximum)
3%0.9 mLTop of body-oil range

We cannot give you a drops-to-percent conversion, because drop size varies by oil and by dropper, and none of the sources we fetched provide one. Measure by mL with a syringe or a graduated pipette, or weigh it. Mix in a clean dark glass bottle and label it with the date and percentage.

Children

The Tisserand Institute's children's chart runs from 0.1-0.2% for babies under 3 months, 0.25-0.5% for 3-24 months, 1-2% for ages 2-6, 1.5-3% for ages 6-15, and states that up to age 6 the figures apply to any topical application (Tisserand Institute). NAHA gives 0.5-2.5% generally for young children. Those percentages are guidelines, and they assume the essential oil is suitable for a child at all, which many are not. The EU monograph says use of calendula on the skin in children under 6 is not recommended because adequate data are lacking. Our recommendation is plain: for a child under 6, ask the pediatrician before blending; do not use a blend as a first step.

Citrus and the sun

If your blend includes citrus, check whether the oil is expressed (pressed from the peel) or distilled. The Tisserand Institute says expressed citrus rind oils can be phototoxic because of furanocoumarins, and distilled citrus oils are not; sweet orange is generally thought not to be phototoxic even when expressed, while expressed grapefruit is slightly phototoxic (Tisserand Institute, Citruses). Note "generally thought" is the Institute's own hedge. A citrus-and-calendula blend belongs under the dilution limit for that oil, and not on skin you are about to put in the sun, if the supplier cannot tell you which type it is. Read the dilution above before copying any ratio from any page, ours included.

Test before you commit to a bottle

A single patch dab is not the dermatology method. In the repeated open application test (ROAT), described in 1986, a product is applied twice daily to the inner forearm for 7 days unless a reaction appears sooner (Hannuksela and Salo, Contact Dermatitis, 1986). A survey of American Contact Dermatitis Society members found no standardized method, with most using one to two weeks (Brown et al., Dermatitis, 2015). It is a clinical protocol, not a consumer instruction, so treat it as a model: test the finished blend, small area, repeated, and stop at any redness, itching or rash. The FDA advises stopping a cosmetic that causes a rash or burn, contacting a healthcare provider, and reporting the reaction (FDA, Using Cosmetics Safely). Allergic rashes can appear hours or days after contact (AAD), so waiting an hour tells you little. Our patch test article covers this in more detail.

NAHA also notes that damaged or inflamed skin is often more permeable to essential oils and sensitization is more likely, and it advises against application to open skin. Keep blends off broken skin and away from the eyes.

What our oil adds to the blend, and what it does not

The one thing we can say from our own process is what is not in the bottle. Our oil has no added preservatives, tocopherol or stabilizers, so every essential oil you add is the only other ingredient and your arithmetic is simple. Which carrier is in a lot is on the batch paperwork (email the lot number to [email protected]). We do not know the carrier's interaction with any particular essential oil, and no source we found tests it. What we cannot offer is evidence that a blend does anything for skin or mood; that is why there are no "therapeutic combos" here.

If you blend, start with the lowest percentage in the table, label it, and keep it for you rather than for a child. For the oil itself, see our calendula oil, and for the difference between infused and distilled oils, calendula infused oil vs essential oil.

Calendula oil bottle

Calendula Oil

Nature's Golden Botanical, bottled: small-batch calendula oil in sizes from 0.5 oz to bulk.

From $13.99

Shop Calendula Oil →

Sources & Further Reading