Phthalates — Why They Are Avoided in Modern Cosmetics

Overview

Phthalates are a family of small synthetic molecules historically used in cosmetics as fragrance fixatives (helping scent last longer), solvents (carrying other ingredients), and plasticizers (keeping plastics flexible — relevant to packaging rather than to formulation). Three phthalates have appeared in cosmetic ingredients over the years: diethyl phthalate (DEP), dibutyl phthalate (DBP), and dimethyl phthalate (DMP). DEP has been the most common in fragrance applications.

Over the past 25 years, growing concerns about possible endocrine-disrupting effects of certain phthalates have led to regulatory restrictions in many countries, particularly in the EU. The current consensus in cosmetic regulation is that:

• DBP and DMP are restricted or banned in cosmetics in most major markets (EU, US, Canada, Australia).
• DEP has been the subject of more ongoing discussion. It remains in use as a denaturant for alcohol in some markets, but most modern fragrance houses have moved away from it as a fixative.

For DIY formulators in 2026, the practical position is straightforward: phthalates have no useful role in DIY cosmetics, and the family is best avoided entirely. There are alternative fragrance fixatives and solvents that do the same jobs without the regulatory and safety concerns.

This entry is educational rather than describing a specific ingredient to use — the purpose is to address the question that comes up often in DIY formulation, “are there phthalates in this fragrance oil?” and to offer practical alternatives.

Why concerns exist

Several phthalates have been shown in laboratory and animal studies to interfere with hormone signaling, particularly testosterone and thyroid hormones. The strength of these effects varies dramatically between specific phthalates — DBP and DEHP (a non-cosmetic phthalate used in plastics) are the most concerning; DEP appears to have weaker effects but is not entirely clear of concern.

Human epidemiological data is suggestive rather than definitive. Several studies have linked higher urinary phthalate levels with various reproductive and developmental effects, but disentangling cause from correlation is difficult.

The regulatory response has been to apply the precautionary principle: where alternatives are available and the safety picture is unclear, restrict use. This is reasonable for cosmetic applications because alternatives genuinely exist.

What to use instead

For DIY formulators wanting the functions that phthalates historically provided:

For fragrance fixation (longer-lasting scent):

• Benzyl Benzoate (low percentages, IFRA-compliant)
• Benzyl Salicylate (IFRA-compliant)
• Iso E Super (synthetic fixative, well-tolerated)
• Ambroxide / amber fragrance materials
• Natural fixatives: vetiver oil, sandalwood essential oil, vanilla absolute

For ingredient solubilization in formulas:

• Caprylyl Glycol
• Propanediol
• Butylene Glycol
• Dipropylene Glycol
• Isopropyl Myristate (for oil-phase solubilization)

For alcohol denaturation:

• Bitterants (denatonium benzoate) — though usage depends on jurisdiction.
• Other denaturants approved in the local market.

Practical guidance for DIY formulators

When buying fragrance oils, request a certificate from the supplier confirming the absence of phthalates (specifically DEP, DBP, DMP). Reputable fragrance suppliers serving the cosmetic industry typically provide phthalate-free certifications.

When buying essential oils, phthalates are not a typical concern — they are not naturally present in essential oils. But poor-quality essential oils may have been adulterated with carrier solvents that could include questionable additives. Buy from suppliers with clear specifications.

For packaging, modern cosmetic packaging plastics (polypropylene, polyethylene, PET) do not typically contain phthalates. PVC-based packaging may contain phthalate plasticizers and is best avoided for cosmetic products.

Common pitfalls

Assuming “natural” or “vegan” labels mean phthalate-free. Natural certifications do not always cover phthalates explicitly. Ask the supplier.

Confusing different phthalates. DEP, DBP, DEHP, DiNP, and others have very different safety profiles and very different use cases. They are not all equally concerning. But for DIY cosmetic use, avoiding all of them is the simpler position.

Overlooking secondary phthalate exposure from packaging. PVC tubes and certain printing inks can leach phthalates into the product. Use polypropylene or HDPE packaging where possible.

Treating regulatory restrictions as the only safety signal. Different markets have restricted different phthalates at different times. The conservative DIY approach is to avoid the family entirely.

Confusing phthalates with parabens or other unrelated families. Phthalates and parabens are completely different chemical families with completely different safety conversations. Do not conflate them.

Substitutes — for the family

• For fragrance use: any phthalate-free fragrance oil from a reputable cosmetic supplier.
• For solubilization: propanediol, butylene glycol, caprylyl glycol.
• For long-lasting scent: natural fixatives or modern synthetic alternatives.
• For packaging: polypropylene, HDPE, or PET. Avoid PVC.