Material guide: bitter almond oil — an empty assay field, a formula reading "unspecified", and a supplier label saying "benzaldehyde >95%"

CAS 8013-76-1, 37 suppliers, FEMA 2046. Its assay field is entirely blank and its formula field reads unspecified, while a supplier entry says "bitter Almond Essential oil Morocco Benzaldehyde (>95%)" — so more than 95% of the oil is a single molecule that has its own record with 108 suppliers. Substantivity reads "< 3 hours", shelf life is only 12 months where most materials say 24, and strength rank is 3. Its oral toxicity field carries an oral-human LDLo of 107 mg/kg, among the lowest of the database's 156 human entries. And Jaswal's 2018 review supplies the mechanism that matters: intravenous administration produces no hydrogen cyanide — it takes gut bacteria hydrolysing amygdalin to make it. Toxicity depends on route.

About 5 minutes.

Short version

Name: bitter almond oil, Prunus amygdalus amara, CAS 8013-76-1
formula: unspecified; assay: blank
Odour type: fruity; odour: fruity, bitter almond, cherry, maraschino cherry, sweet, powdery
Strength: high (smell at 10% or less), rank 3
Substantivity: "< 3 hours"; shelf life only 12 months
Suppliers: 37; FEMA 2046
oral-human LDLo 107 mg/kg; skin-rabbit LD50 1220 mg/kg

Two empty fields

Most records tell you at least a formula and an assay. This one gives neither:

formula: unspecified

assay: (blank)

"Unspecified" appears on 295 records database-wide — the value used for things that are not a single compound. A natural extract has no single molecular formula, so that is reasonable.

A blank assay is not unusual either: of the 3,156 materials with ten or more suppliers, 1,065 (33.7%) have an empty assay field. That is normal at the naturals end.

But this record's situation is particular, because it is very nearly a single substance.

The supplier wrote the purity instead

Two of the supplier entries carried in the solubility field:

Advanced Biotech; BITTER ALMOND OIL NATURAL 98% min. Odor: Cherry almond

Albert Vieille; bitter Almond Essential oil Morocco Benzaldehyde (>95%) Odor: balsamic fragrance that is very almondy and sweet

"Benzaldehyde (>95%)".

And benzaldehyde is its own record in the same database — CAS 100-52-7, 108 suppliers, assay 98.00 to 100.00.

So: one odour, two records. One has a formula, an assay specification and 108 suppliers; the other has "unspecified", a blank assay and 37 suppliers.

Where the specification lives depends on whether you buy the oil or the molecule.

(This is the inverse of pine oil, where the grade is written into the product name. Here the specification never reaches a field at all; it survives only in supplier copy.)

It leaves faster than it smells


Strength	high (rank 3)
Substantivity	under 3 hours
Shelf life	12 months

Rank 3 with under three hours is a steep combination: loud at the start, gone quickly.

And 12 months is short for this series. Most records say 24. Benzaldehyde oxidises readily to benzoic acid, which crystallises, so a short shelf life makes sense.

Note the "<" dropped by the numeric column again — the raw string is "< 3 hour(s) at 100.00 %", and the numeric field keeps 3.0. That is the sixth lost-qualifier case I have collected.

That human figure, and why it belongs to ingestion only

The toxicity_oral field holds three entries, the third human:

oral-rat LD50 960 mg/kg (1979)

oral-rat LD50 > 1490 µL/kg (1979)

oral-human LDLo 107 mg/kg (Food and Cosmetics Toxicology, 1979)

107 mg/kg is among the lowest in the 156 human toxicity records I collected (for comparison: methyl salicylate 355, pine oil 4700).

And there is a specific chemical reason it is low — a reason that only operates when swallowed.

Jaswal and colleagues reviewed amygdalin in Biochemistry and Biophysics Reports in 2018 and set out the mechanism. Amygdalin is a cyanogenic glycoside that hydrolyses to hydrogen cyanide, benzaldehyde and glucose — the almond smell and the toxicity come out of the same reaction. (That reaction itself is in benzaldehyde.)

What matters is who performs the hydrolysis. Their statement:

In-vitro and in-vivo studies using various doses and modes of administration, like IV administration studies that showed no HCN formation, point to the role played by the gut microbiota for the commonly seen poisoning on consumption. The anaerobic Bacteriodetes phylum found in the gut has a high β-glucosidase activity needed for amygdalin hydrolysis to HCN.

Intravenous gives no hydrogen cyanide. Swallowing does, because gut bacteria perform that step.

The implication for a perfumer is direct: that 107 mg/kg is a figure requiring a gut microbiome, and skin does not have one. It cannot be converted into any dermal dose — the general case is in The toxicity field answers the wrong question, and here there is a concrete mechanism for why.

Two things to be clear about, though. Commercial bitter almond oil comes in a "free from prussic acid" (FFPA) grade, and this database's fields do not record it. And the skin-rabbit LD50 of 1220 mg/kg is low for this database, where most read > 5000 — so "a different route" is not "harmless on skin".

Its odour is not only almond

Six words in the odour field, two of them cherry:

fruity, bitter almond, cherry, maraschino cherry, sweet, powdery

Mosciano's description is more precise:

Cherry pit, with a sweet fruity powdery background

"Cherry pit" is the key phrase for this material. Almond, cherry stone, peach stone, apricot kernel — all Rosaceae seeds, all sharing the same cyanogenic glycoside chemistry, and so sharing an odour direction.

The flavour field adds creamy, tropical fruit, rummy and spicy, evaluated at 20 ppm.

How to use it

Evaluate at 10% or less. Rank 3.
It is a top note, and an extreme one. Under three hours; do not expect it to leave anything behind.
Ask about purity and FFPA when buying. The database fields will not tell you; the supplier's specification will.
For stability and a specification, buy benzaldehyde. 108 suppliers, assay 98–100, an actual formula.
Twelve-month shelf life, so buy small. Dark, sealed, cool.
The cherry-pit direction is usable on purpose — it connects to the whole stone-fruit line of cherry, peach and apricot.

What this doesn't establish

I have not smelled it. The whole article is fields, database-wide counts and one paper.
">95% benzaldehyde" is one supplier's product label, not a general rule for the oil. Origin and process move the proportion.
Jaswal's review is about amygdalin as a contested alternative therapy. I quote only its statements on hydrolysis mechanism and route of administration, and do not engage with its efficacy discussion at all.
That review is about amygdalin, not about bitter almond oil. The oil is a distillate; the glycoside is a precursor in the kernel. I use it to explain why ingestion data cannot be extrapolated, not as a claim about this oil's composition.
The FFPA grade is not recorded in this database, and I did not check what any jurisdiction requires of it.
The skin-rabbit LD50 is from 1979, and a dermal acute lethal dose does not answer sensitisation or irritation questions.
I did not check the current IFRA standard for this oil.