How We Calculate NOI

The Natural Origin Index (NOI) is an internationally standardised, mass-fraction-based measure of how much of a cosmetic ingredient comes from renewable biological sources versus petroleum chemistry.

What is the Natural Origin Index?

The Natural Origin Index (NOI) is defined by the ISO 16128 standard — Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients and products (Parts 1 & 2, published 2016–2017). It provides a scientifically reproducible method for quantifying the proportion of an ingredient's molecular mass that is traceable back to a natural, renewable feedstock.

NOI is expressed as a dimensionless number between 0 (wholly petroleum-derived) and 1 (wholly natural-origin). It is calculated by tracing every structural fragment of a molecule back to its industrial feedstock, assigning each fragment a natural-origin fraction (nj), and then computing a mass-weighted average across the whole molecule.

NOI = Σ (mj × nj) / Mtotal

mj = mass of structural fragment j  |  nj = natural-origin fraction of fragment j (0 or 1)  |  Mtotal = total molecular mass of the ingredient

Each fragment receives nj = 1.0 if it originates from a renewable biological or mineral source (plant, animal, microbial, or inorganic mineral), or nj = 0.0 if it originates from petrochemistry. Where a synthetic transformation step adds petroleum-derived mass to an otherwise natural molecule — for example, ethoxylation using ethylene oxide from cracked petroleum — the added petrochemical mass reduces the overall NOI proportionally.

About ISO 16128

ISO 16128 defines "natural origin" as any ingredient derived from plant, animal, microbial, or mineral material using only physical, microbiological, or permitted chemical processes. Chemical transformations that do not substantially alter the natural-origin character (hydrolysis, esterification, fermentation, simple oxidation) are permitted. Transformations that introduce petrochemical-origin atoms into the molecule reduce the natural-origin fraction. We follow the standard's most conservative interpretation, citing publicly available process chemistry and peer-reviewed literature for every ingredient in our database.

A Worked Example: Polysorbate 20

Polysorbate 20 — chemically polyoxyethylene (20) sorbitan monolaurate — is one of the most widely used emulsifiers in cosmetics and personal care. It is an ideal teaching example because it contains both a substantial natural-origin fraction and a large petroleum-derived fraction, making its NOI calculation non-trivial.

The molecule is assembled from three distinct structural regions, each with a different origin:

  • Sorbitan ring — a dehydrated sorbitol (sugar alcohol) backbone, derived from corn or wheat starch. Natural origin (nj = 1.0).
  • Lauric acid tail — a 12-carbon fatty acid from coconut or palm kernel oil, attached via an ester bond. Natural origin (nj = 1.0).
  • Polyethylene glycol (PEG) chains — 20 ethylene oxide (EO) units shared between four polyoxyethylene arms on the sorbitan core (w + x + y + z = 20); the lauric acid is attached as an ester at the end of one arm. Ethylene oxide is produced by oxidation of ethylene from steam-cracked petroleum. Petroleum origin (nj = 0.0).

Polysorbate 20 — Structural Map

NOI ≈ 0.28
Polysorbate 20: sorbitan core and lauric acid tail (natural origin) with four polyoxyethylene arms (petroleum origin) Four polyoxyethylene arms — petroleum origin w + x + y + z = 20 ethylene oxide units · 881 Da Sorbitan monolaurate core — natural origin sorbitan 163 Da + lauroyl 183 Da = 346 Da O C C C C Sorbitan core from corn sorbitol · 163 Da (OCH₂CH₂)w–OH (OCH₂CH₂)x–OH (OCH₂CH₂)y–OH (OCH₂CH₂)z–O– C O CH₃ Lauric acid tail (C₁₂) from coconut / palm kernel oil · 183 Da Natural origin 346 Da ÷ total 1 227 Da = NOI 0.28 · the 881 Da of ethylene oxide counts as petroleum
Natural origin — sorbitan ring (corn sorbitol) + lauric acid tail (coconut/palm)
Petroleum origin — polyoxyethylene chains (ethylene oxide from petroleum)

Fragment-by-fragment mass calculation

Fragment Industrial feedstock Mass (Da) nj mj × nj
Sorbitan core (C₆H₁₁O₅ residue of sorbitol, four O-linkages) Sorbitol from corn or wheat starch, dehydrated 163 1.0 163
Lauroyl acyl chain (C₁₂H₂₃O) Lauric acid from coconut or palm kernel oil 183 1.0 183
20 × ethylene oxide units, (–CH₂CH₂O–)₂₀, in four arms Ethylene oxide from steam-cracked petroleum ethylene 881 0.0 0
Total 1 227 Da — 346 Da
NOI = 346 / 1 227 ≈ 0.28

Only ~28% of Polysorbate 20's molecular mass is natural-origin. The polyoxyethylene arms (881 Da, about 72% of the mass) are petroleum-derived, which pulls the NOI below 0.5 even though the sorbitan and laurate parts are fully natural.

Petroleum (0)Fully Natural (1.0)
NOI = 0.28

Further Examples

Glycerin — NOI = 1.0 (Fully Natural)

Glycerin (glycerol, C₃H₈O₃, MW 92 Da) is produced industrially by saponification or hydrolysis of triglycerides from vegetable oils — palm, soy, coconut — or as a co-product of biodiesel production via transesterification. All three carbons and all three hydroxyl groups are directly traceable to renewable triglyceride feedstocks. No petrochemical atoms are introduced at any step, and the transformations (hydrolysis, simple separation) are ISO-permitted. NOI = 1.0.

Glycerin (Glycerol)

NOI = 1.0
OH OH OH H₂ H H₂ C1 C2 C3 Glycerol · C₃H₈O₃ · MW = 92 Da · NOI = 1.0 All carbons from vegetable-oil triglycerides (palm / soy / coconut)
All atoms natural origin — 100% traceable to vegetable-oil triglycerides

Dimethicone — NOI = 0.0 (Fully Petroleum-Derived)

Dimethicone is polydimethylsiloxane (PDMS) — a silicone polymer with a backbone of alternating silicon and oxygen atoms bearing methyl groups. Although silicon and oxygen are abundant minerals, industrial dimethicone production involves no genuinely natural-origin feedstocks under ISO 16128 criteria:

  • Silicon metal is produced by carbothermal reduction of quartz with petroleum coke in an electric arc furnace.
  • Methyl chloride (CH₃Cl), used to make dimethyldichlorosilane via the Müller-Rochow process, is synthesised from methanol and HCl — both petroleum-derived in industrial-scale production.
  • The resulting chlorosilane is hydrolysed and polymerised to give PDMS.

Because no structural fragment of the final polymer is traceable to a biological or permitted mineral-origin feedstock by the ISO method, NOI = 0.0.

Dimethicone (Polydimethylsiloxane, PDMS)

NOI = 0.0
[ O O O Si CH₃ CH₃ Si CH₃ CH₃ Si CH₃ CH₃ Si CH₃ CH₃ ] n —[Si(CH₃)₂—O]ₙ— · NOI = 0.0 Fully synthetic — silicone polymer from petroleum-derived chlorosilanes
Wholly petroleum-derived — synthetic silicone polymer from petroleum-origin chlorosilanes

The NOI Scale

We group ingredients into five tiers by NOI value, plus a route-dependent flag. The same bands and labels are used everywhere on the site.

100% natural origin

1.00

Every atom from plant, animal, microbial or mineral feedstock. E.g. glycerin, shea butter, copper tripeptide-1, zinc oxide.

Mostly natural

0.51–0.99

A natural core with a petrochemical fragment. E.g. isopropyl myristate 0.78, sodium cocoyl isethionate 0.87.

Half & half

0.50

Exactly half the mass from each origin; rare in practice.

Mostly petroleum

0.01–0.49

A petrochemical backbone carrying a natural fragment. E.g. polysorbate 20 0.28, steareth-20 0.23.

100% petroleum

0.00

Wholly synthetic. E.g. carbomer, phenoxyethanol, dimethicone.

Route-Dependent Ingredients

Some ingredients can be manufactured commercially by either a fully renewable biological route or a conventional petrochemical route. In these cases the NOI is not a fixed property of the molecule — it depends entirely on which manufacturing process was actually used for a given batch.

⚠ We flag these as "Route Dependent"

For route-dependent ingredients we display the full NOI range (often 0.0–1.0) and document each available commercial route. Without a supplier-issued certificate of origin or bio-based content certification (e.g. USDA BioPreferred, DIN CERTCO), the NOI of a specific batch cannot be confirmed. Brands should request feedstock documentation from their raw-material supplier.

Common route-dependent ingredients in cosmetics and personal care:

  • Tocopheryl Acetate (Vitamin E acetate) — Natural-source d-alpha tocopherol from soy or sunflower distillate, acetylated (NOI = 0.91) or fully synthetic dl-alpha from trimethylhydroquinone and isophytol (NOI = 0.0)
  • Lactic Acid — Microbial fermentation of corn/sugarcane sugars (NOI = 1.0) or synthesis from acetaldehyde or lactonitrile, both petroleum-derived (NOI = 0.0)
  • 1,3-Propanediol — DuPont Tate & Lyle bio-route from corn-derived glucose via engineered E. coli (NOI = 1.0) or hydroformylation of ethylene oxide (NOI = 0.0)
  • Caprylyl Glycol — Reduction of coconut caprylic acid (NOI = 1.0) or epoxidation of petrochemical 1-octene (NOI = 0.0)
  • Niacinamide (Vitamin B3) — Fermentation from bio-based glucose (NOI = 1.0) or hydrolysis of 3-cyanopyridine from petroleum-derived pyridine (NOI = 0.0)

Important Caveats & Limitations

NOI is a powerful and standardised tool, but it has clear limitations. Understanding them is essential for interpreting scores correctly.

  1. NOI is not a safety score. A high NOI does not imply that an ingredient is safe, non-irritating, or beneficial. Urushiol (poison ivy oil) has NOI = 1.0. Many petrochemical-derived silicones have an excellent safety record. Always consult toxicological data separately from the NOI.
  2. NOI is not a sustainability score. Palm-derived ingredients can have NOI = 1.0 yet carry serious deforestation risk. The ISO 16128 standard does not account for land use, water consumption, carbon footprint, biodiversity impact, or fair trade practices.
  3. Chemical transformation can dilute NOI. When a natural feedstock undergoes ethoxylation — reacting with petroleum-derived ethylene oxide — the petrochemical mass is added to the molecule, reducing the NOI of the final ingredient even if the starting material was 100% natural. This is why polysorbate 20, despite its natural sorbitan-laurate core, has an NOI of only ~0.28.
  4. "Natural" does not mean "organic". Organic certification requires additional criteria relating to agricultural practices and prohibited pesticide use. An ingredient can be 100% natural-origin (NOI = 1.0) while still not qualifying for an organic certification scheme.
  5. Mineral-origin ingredients are a special case. ISO 16128 treats certain minerals (e.g. zinc oxide, titanium dioxide from natural ore) as natural-origin. However, highly purified synthetic mineral variants may be treated differently. We note the production route where it affects classification.
  6. The standard continues to evolve. ISO 16128 Parts 1 and 2 were published in 2016–2017. Regional interpretations and certifying-body guidelines vary. We update our database as the science and standards evolve, and we cite our sources transparently for every ingredient entry.

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