How We Calculate NOI

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 (n_j), and then computing a mass-weighted average across the whole molecule.

Each fragment receives n_j = 1.0 if it originates from a renewable biological or mineral source (plant, animal, microbial, or inorganic mineral), or n_j = 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.

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 (n_j = 1.0).
• Lauric acid tail — a 12-carbon fatty acid from coconut or palm kernel oil, attached via an ester bond. Natural origin (n_j = 1.0).
• Polyethylene glycol (PEG) chains — 20 ethylene oxide (EO) units distributed across three oxyethylene chains on the sorbitan ring. Ethylene oxide is produced by oxidation of ethylene from steam-cracked petroleum. Petroleum origin (n_j = 0.0).

Fragment-by-fragment mass calculation

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.

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.

The NOI Scale

We group ingredients into four tiers based on their NOI value. These tiers are displayed as colour-coded badges throughout the ingredient database.

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.

Common route-dependent ingredients in cosmetics and personal care:

• Panthenol (Provitamin B5) — Bio-fermentation route from glucose (NOI ≈ 1.0) or petrochemical synthesis from isobutyraldehyde (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)
• Sorbitol — Catalytic hydrogenation of glucose from corn or wheat (NOI ≈ 0.97) or synthesis from furfural derived from petroleum (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 ~0.25.
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.