How to Add Clary Sage Oil to Shampoo: Drops and Percent

A 250 ml bottle of shampoo at 1% clary sage oil holds 2.5 ml of oil, about 50 drops, and a 5 ml squirt of it contains roughly one drop. Those two numbers are the whole case for adding the oil to the bottle and against dropping it into your palm. We sell the oil only, not shampoo, and we have not mixed or tested any shampoo ourselves, so what follows is arithmetic and reasoning from cited guidance, with a patch test as the first step.

Clary Sage Essential Oil bottle

Clary Sage Essential Oil

Our own Clary Sage Essential Oil, in sizes from 0.5 oz to bulk.

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Do the arithmetic before you open the bottle

Our two oils, Botanical and Purity (Salvia sclarea with a published Certificate of Analysis), come undiluted. Our product pages say to dilute to 0.5% to 2% before the oil touches skin. In shampoo, the "carrier" is the shampoo, and the percentage is oil volume over total volume. Using the common convention of 20 drops to the millilitre (the Tisserand Institute notes that drop conversions are always approximate because no two drops are the same, so treat these as round numbers):

Shampoo volume0.5%1%2%
100 ml0.5 ml, 10 drops1 ml, 20 drops2 ml, 40 drops
250 ml1.25 ml, 25 drops2.5 ml, 50 drops5 ml, 100 drops
500 ml2.5 ml, 50 drops5 ml, 100 drops10 ml, 200 drops

Now the per-wash view. If you use 5 ml of shampoo (about a teaspoon), the oil in it is 0.025 ml at 0.5%, 0.05 ml at 1% and 0.1 ml at 2%: one-half, one, and two drops. That is why the common instruction "add a few drops to your palm" is a poor way to hit a percentage. One drop in a palm of shampoo equals 1% only if it is spread evenly through the 5 ml; a drop that stays undispersed is concentrated oil against scalp skin. Mix the bottle once, shake, and let the percentage do the work.

Which percentage: why we stay at the low end

Rinse-off products are usually allowed a higher dilution than leave-on ones because they do not stay on skin. The Tisserand Institute's dilution article by Robert Tisserand says so directly: its bath and wash-off range, which it describes as including soap and body wash, is 2% to 4%, because wash-off products "don't linger on our skin." The article does not mention shampoo. Putting shampoo in that band is an inference, and it is the one we would not lean on, for three reasons.

Reasoning from those sources, the practical consequence is a ladder: begin at 0.5%, stay there for a few washes, and move to 1% only if you want a stronger scent and the scalp has stayed calm. We would not go above 1% in shampoo without a reason, and we would not use the 2% column at all for a first bottle. For wider dilution background, see how to dilute clary sage oil.

What you are actually adding it to

We do not sell shampoo, carrier oils or any other base, so you are choosing one, and its formula is not ours. Two practical points follow.

Separation. Essential oils are oils, and oil does not dissolve in water. A shampoo base contains surfactants that may hold small amounts dispersed, but we have not tested how any base takes clary sage oil, so we cannot say how long it stays mixed. Reasoning from that: make a small batch, shake before each use, and treat a visible film or oily beads as a sign the oil is not distributed, in which case the percentage on the scalp is not the percentage you calculated. A bottle you will use within a few weeks is easier to get right than a litre.

Preservation. A shampoo is mostly water, and a review of cosmetic preservation by Halla et al., Molecules, 2018 says that water is "an ideal growth factor for microorganisms" and that water-containing cosmetics need preservation. The same review lists reasons essential oils are often discouraged as a preservative on their own, including loss of activity on dilution, pH dependence, volatility and strong odour. So adding clary sage oil to a finished, already preserved shampoo is one thing; trying to build your own shampoo and counting on the oil to keep it from spoiling is another. We would only do the first, and we do not know how an added oil changes the base's own preservative system, which is another reason to keep the amount small and the batch small.

Check before you commit

  1. Patch test the finished mix, not just the oil. Follow our patch test guide, using the diluted shampoo and not the neat oil. Wait for the result before putting it on your scalp.
  2. First washes. Use the bottle on a small number of washes. Stop if there is itching, redness, stinging or a rash, and rinse thoroughly.
  3. Keep it out of eyes. If it gets in, rinse with plenty of water, and see a doctor if irritation continues.
  4. Store the oil right. Keep the undiluted bottle capped, in a cool dark place, away from children and pets (our own pages).

What this will not do, and who should skip it

We make no claim that clary sage oil in shampoo changes hair growth, shedding, dandruff or scalp condition. We found no trial that tested it on hair; for what has and has not been tested, see our rosemary comparison. Add it for the scent, if you like it.

For a leave-on alternative where the arithmetic is easier to control, see our scalp oil post. A shampoo is a perfectly good way to enjoy the oil's scent if you keep the percentage low, mix it evenly, and patch test first.

Clary Sage Essential Oil bottle

Clary Sage Essential Oil

Clary Sage Essential Oil from our own shop, in sizes from 0.5 oz to bulk.

From $19.99

Shop Now →

Sources & Further Reading