Tamanu oil: a thick, dark, strong smelling oil with a real tradition behind it

Tamanu oil is 35 to 50 percent oleic with an iodine value of 82 to 98, a heavy viscosity and a nutty smell. Use at 1 to 10 percent, plus the allergy caution.

Tamanu is one of the few carrier oils that announces itself. At 5 percent it visibly greens a pale balm, thickens the pour and puts a nutty, resinous smell into a product that was meant to be unscented. That is not a fault in the oil, it is the same resin fraction that carries the compounds people buy it for. This page gives the composition with its methods, weighs the calophyllolide evidence honestly, and sets a working range that accounts for what your customers will actually notice.

• INCI: Calophyllum Inophyllum Seed Oil
• Iodine value 82-98
• Unsaponifiables 2-7%
• Use at 1-10%
• Strong odour and colour

What tamanu oil is, and why the kernels are cured

Calophyllum inophyllum is a coastal tree of the Indian and Pacific Ocean tropics, known as tamanu in Polynesia, foraha in Madagascar, kamani in Hawaii and punnai in southern India. It fruits heavily, producing a round green drupe with a single large kernel inside a woody shell. The oil comes from that kernel.

The processing step that makes tamanu unlike other seed oils is curing. A freshly opened kernel is pale, damp and yields very little oil. Traditionally the kernels are cracked out and left to dry in shade for several weeks, commonly four to eight, during which they darken, become sticky and turn oily to the touch. Only after curing does pressing give a usable yield, and cured kernels are commonly quoted at somewhere between 50 and 70 percent oil by weight.

Two consequences follow that you will meet on the specification sheet. Curing lets the kernel's own lipases work on the triglycerides, so crude cold pressed tamanu carries a much higher free fatty acid content than an ordinary pressed seed oil: acid values in the tens of milligrams of potassium hydroxide per gram are normal where a refined oil would be under 2. And the long cure develops the dark resin that gives the oil its colour, its viscosity and its smell. Neither is a sign of a badly handled batch. Both are what the material is.

Fatty acid profile and identity values

The fatty acid composition is unremarkable on its own. It is roughly what you would expect from a mid-oleic tropical seed oil, and it is not the reason anyone buys tamanu.

With a quarter to a third linoleic acid and almost no linolenic, tamanu belongs in the same oxidative band as high oleic oils and sweet almond, not with the fragile drying oils. Expect 12 to 24 months unopened in a cool dark place. It shows its age by thickening and by the nutty note turning sharp rather than by the paint smell that gives away a linolenic oil, and the general mechanism is in rancidity and oxidation. Against three dozen other oils it sits in the oil comparison table.

The resin, the unsaponifiables, and why it is so thick

The fatty acid profile predicts an oil of unremarkable viscosity. Tamanu is not that. Crude cold pressed oil pours like thin honey at room temperature and drags noticeably between the fingers, and the reason is the fraction that is not triglyceride at all.

Unsaponifiable matter in most seed oils runs 0.5 to 2 percent. In tamanu it is commonly reported at 2 to 7 percent, and in crude, unfiltered oil the total non-glyceride fraction, counting the dark resin developed during the cure, is higher again. That resin is a mixture of coumarin derivatives, triterpenes, sterols and polyphenolic material. It is polar, it is high molecular weight, and it thickens the oil out of proportion to its mass in the way a small amount of dissolved polymer thickens a solvent.

Practically, tamanu behaves as though it were part liquid oil and part soft butter. Ten percent in the oil phase measurably slows spread and adds cling, which is useful in a heavy hand or foot product and unwelcome in anything meant to sink quickly. If you are building a light face balm, the drag is a real cost, and you would do better with a small percentage carried in a wider oil blend. The trade-offs across the whole liquid phase are set out in carrier oils compared.

Calophyllolide and the neoflavonoids, assessed honestly

The resin fraction carries a group of 4-phenylcoumarins, or neoflavonoids, that are close to unique to the genus. Calophyllolide is the best known, alongside inophyllolide, the inophyllums and calophyllic acid. These are real, well characterised compounds and their isolation from Calophyllum inophyllum is not in question.

What is in question is what they do on human skin in a cosmetic product. The published work falls into three groups. In vitro assays show antibacterial activity against skin organisms including Cutibacterium acnes and Staphylococcus aureus, and antioxidant activity in standard chemical assays. Rodent studies report reduced oedema in inflammation models and faster closure in wound models. And separately, the inophyllums have attracted pharmacological interest as enzyme inhibitors in work that has nothing to do with skin and should not be quoted in a cosmetic context at all.

What does not exist, as far as the published literature goes, is an adequately controlled human trial of tamanu oil on skin at a cosmetic inclusion level. Every step in the chain from a petri dish to a rodent flank to a 5 percent inclusion in a balm on a person costs you certainty, and the last step costs the most. There is a plausible mechanism and a long ethnobotanical record. There is not clinical evidence, and a page that told you otherwise would be selling you something.

What 5 percent does to a pale balm

Crude tamanu is dark green to greenish brown, and it is a strong colourant by accident. A shea and beeswax balm that was ivory becomes visibly olive at a few percent, and because the colour comes from dissolved plant material rather than from a dispersed pigment it goes in evenly and cannot be filtered out of the finished product. In a tin this reads as herbal and deliberate. In a white-labelled lip balm it reads as a fault.

Plan the colour rather than discovering it. If a green cast is wrong for the product, either drop to 1 or 2 percent, use a refined grade and accept what you lose with it, or lean into the colour and let the balm be visibly botanical. Adding a pigment on top to correct a tint rarely works, because you are trying to cover a transparent dye with an opaque powder, and colourants and tints explains why that fight is usually lost.

Use levels and the smell threshold

One to ten percent of the finished formula is the honest working range, and most products should sit at the bottom of it.

The smell is the binding constraint far more often than the skin feel. Tamanu is nutty and resinous with a faintly medicinal edge, and it is persistent: it does not flash off the way a top note does, so it sits underneath everything you put on top of it. In an unfragranced product, most testers notice it from around 3 percent. In a lightly fragranced one you can hide 5 percent under a resinous or herbal scent profile, and you will struggle to hide it under a clean floral or a citrus at any level. If a product has come back smelling of something other than what you intended, balm smells too strong works through the options, most of which are cheaper than reformulating.

The products where 5 to 10 percent genuinely earns its place are the heavy, deliberately herbal ones: a gardener's or a mechanic's hand salve, a foot balm, a cuticle balm, anything where a dark green colour and a botanical smell are the point. The gardener's hand salve formula is the obvious home for it, and tamanu combines naturally with an infused oil base of the kind described in herbal infused oils, where the colour and scent are already going in that direction.

Allergy, latex and the tree nut question

Two cautions circulate about tamanu, and they deserve to be separated because one is better founded than the other.

The first is tree nut allergy. Botanically the tamanu kernel is a drupe seed, not a true tree nut, and Calophyllaceae is unrelated to the families that produce almonds, walnuts or cashews, so there is no reason from taxonomy to expect cross reactivity. That is not the same as a safety clearance. A cold pressed, unrefined oil carries protein residues in a way a refined one does not, and a customer with a nut allergy reading an ingredient list will make their own judgement about a seed oil pressed from something that looks like a nut. Declare it plainly, do not put it in a product positioned as allergen aware, and see nut oil allergy for how the protein residue question works across pressed oils generally. If you need a formula with none of this ambiguity, nut free balm starts from a different set of oils.

The second is the latex caution, which is repeated widely in trade material. Calophyllum species do exude a latex-like sap, and the caution is precautionary reasoning from that fact. It is not backed by the kind of published cross reactivity data that exists for natural rubber latex and foods such as banana and avocado. Treat it as an unquantified caution rather than a known risk, and treat it as one more reason to patch test.

Individual sensitisation to tamanu is reported at case level rather than in population studies, which means it exists and nobody knows the rate. For a new ingredient with a rich unsaponifiable fraction, a 48 hour patch test is the sensible default, and how to patch test a balm sets out the method for a finished product rather than a raw material.

Grades, sediment and filtration

Three grades are sold and the gap between them is larger than for most oils.

Crude oil drops a dark sludge over weeks in the bottle. That sediment is resin and fine kernel solids coming out of a saturated solution, not spoilage, and it is not mould. It also does not disperse evenly if you tip the bottle straight into a melt, so a batch made from the last third of a bottle can differ visibly from one made from the first. If you want consistency, warm the whole bottle to about 40 C, mix it thoroughly and either use it all or filter it: a warm pass through a coffee filter or a fine muslin removes the solids without stripping the dissolved resin. Filtering cold is slow and clogs. Keeping batch to batch appearance stable is one of the reasons to record which grade and which lot went into which pour, as in sourcing ingredients.

Cold pressed grades also vary with origin and cure practice more than most oils, so a certificate of analysis showing acid value, peroxide value and refractive index is worth asking for, and worth reading rather than filing. A peroxide value quoted as a specification ceiling tells you nothing; ask for the measured figure and its date.

What you can and cannot say about it

Tamanu attracts drug-adjacent claims more than almost any other carrier oil, and the regulatory line does not care how old the tradition is.

In the UK and the EU, a cosmetic product is defined by its purpose: cleaning, perfuming, changing appearance, protecting, keeping in good condition or correcting body odours. A product presented as treating, preventing or curing a disease is a medicine, and presentation includes what you say on your website and your market stall as well as the label. Claims must also meet the common criteria for cosmetic claims, which require evidential support proportionate to the claim.

So "heals wounds", "treats acne", "removes scars", "anti-inflammatory" and "regenerates skin" are all outside what a tamanu balm can be sold on, and the last two are outside it even though there is in vitro and animal work behind them, because the claim as a consumer reads it is a medicinal one. What is available is narrower and duller: an oil rich in a distinctive unsaponifiable fraction, used in a balm that helps skin feel comfortable and look conditioned. The boundary and the evidence standard are set out in cosmetic versus drug claims, and where a product is aimed at people with a diagnosed skin condition, balm for eczema evidence shows how far the honest version of that conversation goes.

Aftercare is the other trap. Tamanu appears constantly in tattoo and post-procedure balms on the strength of its traditional use. A practitioner's aftercare instructions come first, always, and a balm sold into that gap should say so rather than imply a therapeutic role, as balms and tattoo aftercare explains.

Where tamanu does not belong

The decision is not whether tamanu is a good oil. It is whether its three costs, colour, smell and price, buy you anything in the specific product in front of you.

Leave it out of pale or delicately fragranced products, out of anything sold on a clean or minimal aesthetic, and out of lip products, where the taste and the colour are both against you. Leave it out of a formula whose selling point is a light, fast sinking finish, because the resin fraction works directly against that. And leave it out when the only reason it is on the list is the ingredient deck, because at 0.5 percent it does nothing measurable and the label claim is doing all the work.

Put it in when the product is already dark, heavy and botanical, when a nutty resinous smell is consistent with what you are making, and when the customer is buying a herbal salve rather than a moisturiser. At 3 to 8 percent in a hand or foot salve it is a genuinely characterful ingredient with a long record of use, and it holds up better in storage than the fragile oils it is often shelved beside. Just do not expect it to do more than that, and do not build a product's entire proposition on a coumarin fraction that has never been tested on skin in a controlled trial.

Reviewed and updated 6 September 2026. Spotted an error? Tell us and we will fix and log it.