Harmful Skincare Ingredients to Avoid

by Rodrigo Diaz
December 15, 2025
6 min read

Mechanism: Hormonal disruption, cellular toxicity, carcinogenic or allergenic potential, and environmental accumulation | Target: Skin barrier, hormone receptors, mitochondria, immune signaling | Exclusion Rationale: Compounds with poor biocompatibility or long-term safety risks are excluded from high-performance longevity skincare.

Executive Summary

In performance-led skincare ingredient integrity is king. The following report identifies chemical compounds, preservatives, and novel bio-additives commonly found in the market that present known toxicological, hormonal, or cellular risks. These include parabens, phthalates, sulfates, synthetic fragrances, formaldehyde-releasing agents, PEGs, and unregulated exosome derivatives. While often included for aesthetics or trend value, these ingredients introduce unacceptable variables: endocrine disruption, carcinogenicity, irritancy, and in some cases, unproven or biologically unstable biotechnology. This research supports the exclusion-first approach behind GOA’s formulation strategy: omit what harms, deliver what works.

Even high-end skincare brands sometimes include ingredients that science-driven consumers might question. Below we break down some controversial additives, from cutting-edge technologies to common “dirty” chemicals, and why a performance-focused skincare line might exclude them.

Executive Highlights

Exosomes and similar biotech actives in cosmetics currently lack standardized quality control, transparent sourcing, and robust long-term safety data.
Legacy ingredients such as parabens, phthalates, sulfates, formaldehyde-releasing preservatives, PEGs, and undisclosed fragrance mixes carry documented endocrine, irritant, carcinogenic, or ecological concerns.
GOA Skincare follows an exclusion-first standard that removes compounds with credible concerns around long-term toxicity, biological disruption, or environmental accumulation.

Exosomes in Skincare: High-Tech Hype with Safety Concerns

Exosomes are tiny vesicles (cell messengers) being marketed as next-gen anti-aging actives. They sound cutting-edge, but experts urge caution. In research, exosomes can carry powerful signals between cells, yet in cosmetics they often amount to hype with unproven benefits and unclear safety. Key issues include:

Unstandardized Quality

Unlike medical-grade exosomes, which are rigorously characterized for size, purity, and contents, cosmetic exosome products lack transparency. Companies rarely disclose their source or test for markers of purity. In short, a vague “cell culture extract” may appear on labels with no guarantee of intact, functional exosomes.

Biological Risks

Exosomes can carry unpredictable cargo, including proteins or microRNAs that might trigger cell proliferation or inflammation. Without strict screening, a skincare serum’s exosomes could theoretically send the wrong signals, even potentially oncogenic ones. Regulators have warned that unapproved exosome therapies pose risks of infection or immune reactions.

Ethical and Source Issues

Some lab-made exosomes come from human or animal cell lines (for example, neonatal foreskin fibroblasts). Brands often do not disclose this, raising ethical questions about sourcing. “Plant-based” exosome claims also lack clarity, as there is no standard defining what these are.

Stability and Delivery

True exosomes are fragile. Without special handling, such as frozen storage, they degrade quickly. Because they are relatively large (30–150 nm), they also struggle to penetrate an intact skin barrier. Current data suggest that topically applied exosomes are unlikely to reach living skin cells in meaningful amounts, so any anti-aging claims remain speculative.

Overall, exosomes in skincare are exciting in theory but currently unsupported by robust evidence and safety data. Dermatology reviews note a lack of clinical studies and substantial safety concerns, including risks of unwanted inflammation or stimulation of malignancy. Until independent research and regulations catch up, many science-led brands avoid exosomes as too high-risk and unproven.

Common Harmful Ingredients to Avoid

Beyond new fads like exosomes, many long-established chemicals in skincare have toxic or irritating effects. A clean, high-performance formulation steers clear of the following groups.

Parabens

Parabens (for example, methylparaben, propylparaben) are cheap preservatives found in lotions and cleansers. They are known endocrine disruptors that can mimic hormones in the body. Certain parabens, such as propyl- and butylparaben, have shown estrogenic activity linked to breast cell growth and reduced male fertility in studies. Animal research has reported reductions in sperm production and testosterone levels after exposure. These chemicals absorb through skin and can accumulate with daily use, and they have been detected in breast tumor tissue.

Phthalates

Phthalates (for example, DEP, DBP) often hide under the term “fragrance.” They act as plasticizers and scent fixatives but pose serious health concerns. They are strongly linked to endocrine disruption and reproductive toxicity. The EU has banned several phthalates in cosmetics as toxic to reproduction. Studies associate prenatal exposure to phthalates with feminization effects in male infants, and in adults, higher phthalate metabolite levels correlate with lower sperm quality and hormonal changes.

Sulfate Cleansers (SLS/SLES)

Sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES) are detergents used to create lather in face wash, body wash, and shampoo. SLS is a well-known irritant that can strip natural oils and disrupt the skin barrier. SLES is considered milder but can become contaminated during manufacturing with 1,4-dioxane, a byproduct classified as a possible human carcinogen. 1,4-Dioxane is not intentionally added, so it does not appear on labels.

“Fragrance” (Synthetic Perfumes)

The term “fragrance” or “parfum” on an ingredient list can represent dozens of chemicals. Companies aren’t required to disclose these proprietary blends. Many common perfume ingredients are allergens or hormone disruptors, and fragrance mixes have been tied to skin allergies and dermatitis, respiratory issues, and reproductive effects. Compounds such as diethyl phthalate are frequently used in fragrances and can enter the body. Synthetic musk molecules have been found to persist in human fat tissue and may act as endocrine disruptors.

Formaldehyde-Releasing Preservatives

Formaldehyde-releasing preservatives include DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, quaternium-15, and similar compounds. They prevent microbial growth by slowly releasing formaldehyde. Formaldehyde is a known human carcinogen and a potent skin sensitizer. Even low levels can cause allergic reactions. Some of these preservatives, such as quaternium-15, are particularly associated with contact dermatitis.

PEGs (Polyethylene Glycols)

PEGs are petroleum-derived emulsifiers and solvents, often listed as “PEG-” followed by a number or under names like polysorbates. They are produced through ethoxylation, a process that uses ethylene oxide, a carcinogenic gas. This can contaminate PEGs with ethylene oxide and with 1,4-dioxane. These impurities do not appear on ingredient lists. PEGs also act as penetration enhancers, which can make skin more permeable to other chemicals in a formula. Some PEG compounds can irritate skin or have shown genotoxicity in lab models.

Other Notable Ingredients

Triclosan and Triclocarban: Antibacterial additives formerly common in soaps and deodorants. The FDA banned triclosan from hand soaps due to concerns it disrupts hormones and may contribute to antibiotic resistance. Animal studies link triclosan to developmental and immune issues.

Oxybenzone and Octinoxate: Chemical UV filters found in many sunscreens and moisturizers with SPF. They absorb UV light, but also absorb into the body. Oxybenzone in particular is detected in the bloodstream and has been implicated as an endocrine disruptor. These chemicals are also environmentally harmful.

Methylisothiazolinone (MIT): A preservative that effectively kills microbes but is a major allergen. It was widely used in “paraben-free” products until dermatologists saw a spike in severe allergic reactions. MIT is now restricted in leave-on products in the EU.

Heavy Metals: Not intentionally added, but cosmetics can be contaminated with lead, arsenic, cadmium, and similar metals. High-performance skincare involves careful sourcing and testing of raw materials to reduce this risk.

GOA’s Exclusion-First Standard

Each of the ingredients above has documented risks, including hormone disruption, cancer links, allergic potential, or ecological damage. For those who want to dive deeper into ingredient safety, trusted resources like the Environmental Working Group and Campaign for Safe Cosmetics maintain publicly searchable ingredient databases.

GOA Skincare adheres to a stricter internal standard by excluding any compound with credible concerns around long-term toxicity, biological disruption, or ecological harm.

You can view our full formulation standard and safety-first approach on the GOA Skincare Ethos page.