Siloxanes in Cosmetics: India’s Beauty Safety Blind Spot

A hair serum can feel weightless without disappearing without a trace.

Some of the ingredients that help it spread and dry evaporate into the surrounding air. Others can enter wastewater when products are washed away. What feels pleasant on hair or skin is only one part of a chemical's story.

That is why research from India's CSIR National Environmental Engineering Research Institute, or NEERI, deserves attention. It asks what is in beauty products, how people may be exposed and where those substances go after use.

The findings concern particular volatile siloxanes. They do not justify treating every silicone ingredient as dangerous.

What did the Indian cosmetics study find?

Researchers Ishan Singh, Gajanan Sitaramji Kanade and Asirvatham Ramesh Kumar examined 174 beauty and personal care products sold in India for cyclic and linear volatile methylsiloxanes. Their paper appeared in Science of the Total Environment in 2025.

In its public summary of the research, NEERI reported that approximately 40% of samples exceeded the 0.1% European benchmark used in the comparison.

The paper's exposure assessment also estimated inhalation exposure to combined D4 and D5 above the chronic reference dose used by the researchers.

These are signals for further investigation, not evidence that 40% of Indian cosmetics are unsafe, that sampled products violated Indian law, or that any consumer developed illness.

A product survey and an exposure model answer different questions from a clinical study.

Which silicones are we talking about?

Silicones are a broad group of materials. The small cyclic molecules D4, D5 and D6 should not be treated as interchangeable with silicone polymers such as dimethicone.

The names shoppers are likely to encounter on an ingredient list are:

Health Canada describes cyclomethicone as a material of variable composition primarily comprising D4, D5 and D6. You can look up any unfamiliar name in The Clean Sheet's ingredient glossary.

These ingredients are not obscure. At the time of review, L'Oréal Paris's Indian webpage for Extraordinary Oil Hair Serum listed cyclopentasiloxane first.

That establishes a declared ingredient, not its exact concentration or a finding of harm. It does not establish that the product was sampled by NEERI. Formulations can also change, so the current pack matters.

What the findings mean for a buyer

What Europe's 0.1% restriction actually means

Under REACH Regulation (EU) 2024/1328, the restriction applies at 0.1% or more by weight of each covered substance, with different application dates.

D4 and D5 in cosmetics washed off with water were already covered from 31 January 2020. The expanded restriction covering the other cosmetic uses applies after 6 June 2027. As of this article's publication, that cosmetics transition date is still ahead.

There is also a separate rule: D4 was added to the EU Cosmetics Regulation's prohibited substances list by Regulation (EU) 2019/831. The 2027 date should not be read as general permission to formulate with D4 until then.

The REACH restriction addresses environmental releases and persistence and bioaccumulation concerns. Its concentration limit is not a clinical threshold at which a product suddenly becomes toxic to its user.

Nor does an EU benchmark establish whether a product complies with Indian requirements. That needs a separate assessment against the applicable Indian rules and standards.

Does using D5 mean putting your health at risk?

The answer depends on the exposure being assessed.

In its 2016 opinion on D5, the European Scientific Committee on Consumer Safety considered cosmetic use safe at the reported concentrations, except for hair styling aerosols and sun care sprays under the assessed conditions. In those cases, inhalation was a concern. Oral care was outside the opinion's scope.

The committee also recommended keeping D4 impurities in D5 as low as possible. Crucially, its opinion did not assess environmental impact.

Health Canada's published assessment summary records conclusions that D5 and D6 were not harmful to human health at the exposures assessed. Its environmental conclusions also differ from the European position.

These assessments are not unlimited assurances for every formulation and usage pattern. They show why a statement about environmental persistence cannot simply be substituted for a conclusion about harm from skin contact.

The Indian exposure estimate deserves follow-up through measurements of actual use, indoor concentrations and relevant populations. An estimated exceedance is a reason to investigate the assumptions and exposure more closely, not a count of injured consumers.

Hair styling brings indoor air into the discussion

A Purdue University research study published in 2023 measured emissions during realistic hair care routines. D5 contributed most to the cyclic siloxanes emitted. Total cyclic siloxane emissions ranged from approximately 110 to 1,500 milligrams per person across the experiments, depending on products, styling tools, temperatures and hair length.

Those numbers describe emissions into the room. They are not the amount absorbed into a person's body.

The study found that heating could increase emissions and examined ventilation as a way to reduce inhalation exposure. Its findings support using effective ventilation during styling, while leaving open questions about exposure in Indian homes and salons.

For India, research should examine small bathrooms, different ventilation arrangements and repeated professional use. A stylist's working day is not equivalent to one customer's short routine.

Ventilation also moves chemicals outdoors. Reducing indoor exposure and reducing total environmental release are separate objectives.

The environmental concern is already measurable in India

A subsequent NEERI paper in Environmental Pollution, published in the January 2026 volume, examined the Nag and Pili rivers in Nagpur.

Researchers sampled water and sediment at 33 locations during January and May 2024. D4 and D5 were prominent, and the estimated annual riverine input of total volatile methylsiloxanes was 1.29 tonnes. Calculated hazard quotients indicated potential ecological risk.

This was a study of one urban river system, not a national contamination estimate. The annual flux was estimated, and the work does not establish that cosmetics supplied all of it. Siloxanes have other applications.

Nevertheless, it adds a different kind of evidence: environmental measurements alongside consumer product research. That supports investigating sources, wastewater pathways and treatment performance.

India should not need proof of human disease before examining a credible environmental contamination signal.

Small packs should not mean less ingredient transparency

Consumers cannot independently assess what they cannot identify.

Under Rule 34(7) of India's Cosmetics Rules, 2020, ingredients above 1% are generally listed in descending order, followed by those at 1% or below in any order. The ingredient statement is exempted for packs containing 60 ml or less of liquid, or 30 g or less of solid or semisolid cosmetic.

That can include the small concealers, primers and serums people use regularly. An absent ingredient list on an exempt pack does not, on its own, establish a legal breach. Equally, compliance with that exemption does not give a shopper the information needed to choose. Our guide to five red flags worth checking in an ingredient list covers the wider labelling gaps buyers run into.

The Clean Sheet's proposal is simple: complete ingredient information should be accessible for every product size. Space constraints could be addressed through a product webpage or QR code, with an accessible alternative for shoppers without smartphones.

This means disclosing ingredient names, not publishing a proprietary manufacturing recipe. Concentration and impurity records would still need to be available for qualified assessment.

What should shoppers do now?

There is no basis in these studies for declaring every silicone product unsafe or discarding an entire routine.

Read the full ingredient list. If your concern is specifically D4, D5 or D6, look for their names rather than treating every silicone as the same substance. Cyclomethicone may require clarification from the manufacturer.

Follow product instructions, avoid deliberately breathing sprays and use effective ventilation when styling. Do not assume that a product marketed for heat protection has also been shown to minimise airborne emissions.

If choosing an alternative, evaluate the replacement formula. “Silicone free” does not demonstrate better preservation, lower irritation, better performance or a smaller environmental footprint.

The Clean Sheet's Claims Library explains the broader principle: an ingredient absence claim cannot carry every other promise a buyer might attach to it.

What India should ask of regulators and brands

• Measure the categories that matter. A wider surveillance programme should quantify D4, D5 and D6 in products with substantial use or exposure potential, across brands, batches and price points. Publishing the sampling method would help readers understand what the findings represent.
• Review restrictions against Indian evidence. Evaluate current ingredient controls alongside environmental releases, local use patterns and inhalation exposure. The EU's reasoning is useful evidence, but its number should not be copied without explaining the policy objective. Our wider comparison of cosmetic regulations across India, the EU and the US covers how these frameworks diverge.
• Make disclosure useful. Require accessible ingredient lists across pack sizes and keep online information aligned with the formula being sold.
• Assess replacements as carefully as existing ingredients. Reformulation should examine performance, human exposure and environmental effects together. Removing a scrutinised ingredient is not enough if its replacement is poorly understood.

For brands, the question is whether they can explain the function, concentration, impurity control and exposure assessment behind a formula. For regulators, it is whether product oversight adequately considers what happens during use and after disposal.

The Clean Sheet's perspective is that skin tolerance, inhalation exposure, environmental fate and disclosure deserve separate evidence. A reassuring answer to one cannot settle the others.

India's beauty market can grow while asking harder questions about its ingredients. The NEERI findings give it a concrete place to begin.

Sources and further reading

1. 1Singh, I., Kanade, G.S. and Kumar, A.R. (2025), volatile methylsiloxanes in personal care products sold in India, Science of the Total Environment (PubMed abstract). View source
2. 2CSIR-NEERI, public summary of the cosmetics siloxane survey. View source
3. 3Health Canada, Siloxanes Group: chemicals management plan substance information, including the description of cyclomethicone. View source
4. 4European Commission, REACH Regulation (EU) 2024/1328 restricting D4, D5 and D6. View source
5. 5European Commission, Regulation (EU) 2019/831 adding D4 to the EU Cosmetics Regulation's prohibited substances list. View source
6. 6European Scientific Committee on Consumer Safety (SCCS), 2016 opinion on Cyclopentasiloxane (D5) in cosmetic products. View source
7. 7Health Canada, Siloxanes Group fact sheet summarising human health and environmental assessment conclusions. View source
8. 8Purdue University (2023), study of cyclic volatile methylsiloxane emissions during hair care routines (PubMed). View source
9. 9NEERI (2026), volatile methylsiloxanes in the Nag and Pili rivers, Nagpur, Environmental Pollution (ScienceDirect). View source
10. 10CDSCO, Cosmetics Rules, 2020 (India). Rule 34(7) covers ingredient labelling order and the small-pack exemption. View source
11. 11L'Oréal Paris India, Extraordinary Oil Hair Serum product page (ingredient list reference). View source

This is a consumer guide, not legal or medical advice. Regulatory references are summarised from the published sources above and should be confirmed against the originals. Product sample counts and findings are not presented as representative of the whole Indian market. Images courtesy of Pexels and their photographers, used under the Pexels License.