Ilcsi Sulphuric Serum

Xanthan gum is a pretty common and great ingredient. It is a natural, non-toxic, non-irritating ingredient that is also commonly used in food products.

Furanocoumarins bind and destabilize your DNA to increase the rate of sunburn.

Most reputable companies will remove furanocoumarins from their formulations.

At higher doses or for those with sensitive skin, methol-type cooling can quickly turn into burning/irritation. It can also trigger irritant dermatitis or even allergic contact dermatitis. In a large patch-test dataset, peppermint oil had a low but positive rate for this.

In cosmetics, Cosmetic Safety Reviews (CIR) concludes that peppermint oil is safe to use when formulated to be non-sensitizing with some restrictions; for instance, pulegone, a naturally occurring component of peppermint oil, should not exceed 1%.

Since peppermint oil contains fragrance allergens such as limonene, linalool, and menthol, it can be sensitizing for those with rosacea, eczema, a broken skin barrier, or just sensitive skin in general.

In Japan, this ingredient is known as Hakka Yu.

The antioxidant activity comes from its flavonoid, polyphenol, and sterol content.

Studies show low concentrations of this ingredient did not cause skin irritation:

Capsicum Frutescens Fruit Extract is often used in the same studies due to their similarities. However, a study found Capsicum Annuum to have higher antibacterial activity.

Another study found Capsicum Annuum to absorb a tiny bit of UV, but this should not replace your sunscreen.

When sulfur touches skin, it reacts with an amino acid in skin cells (called cysteine) to create cystine and hydrogen sulfide.

That hydrogen sulfide helps loosen dead skin cells to exfoliate. And here's a geeky detail: the smaller the Sulfur particles, the more they interact with skin and the better they work.

Sulfur also has antifungal and antibacterial activity, which is why you'll see it in both acne treatments and dandruff shampoos.

In the US, acne products can use 3-10% sulfur while dandruff products use 2-5%. It's also often paired with Sodium Sulfacetamide, and using that combo twice daily for 12 weeks reduced inflammatory acne spots by about 80%.

The most common complains are the smell and dryness. Otherwise, side effects are uncommon.

If you have a "sulfa" allergy, that's an allergy to sulfonamide drugs and this doesn't mean you'll react to elemental sulfur.

A 1972 study suggested sulfur might clog pores. Elemental sulfur caused some clogged pores on rabbit ears and human backs (though the researchers noted the effect was mild).

A 1978 follow-up tested this on 52 people. After six weeks of patches with 5% Sulfur, skin biopsies showed no link between Sulfur and clogged pores. The surprise? The base the Sulfur was mixed into was what caused clogged pores. Later reviewers also noted that other studies couldn't repeat the 1972 results.

So why does Sulfur have a comedogenic rating of 3?

That number comes from a 1989 rabbit ear study by dermatologist James Fulton, which gave a 3 to water-soluble sulfur specifically. Even so, a 3 isn't a big red flag. Fulton's own scale treats 2 to 3 as borderline.

Human testing has also proved that any finished product with a comedogenic ingredient won't automatically make you break out; it really comes down to concentration, formula, and your skin.

You should know this ingredient is a known EU fragrance allergen.

Animal studies classifies this ingredient as a weak-to-moderate skin sensitizer and clinical patch testing on eczema patients confirmed it to be both a contact allergen and irritant.

The term 'citral' is a collective term for two geometric isomers: geranial/Citral A and neral/Citral B.

The term 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term. For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance.

You'll typically see this ingredient used in very small amounts; anything above 0.001% in a leave-on product or 0.01% in a rinse-off has to be named on the label in the EU. The citrus oils that carry it sit around 0.5-1% in a finished formula.

Fresh limonene is a weak allergen; the real issue is that it slowly reacts with air and then breaks down from oxidation to create hydroperoxides (which are strong sensitizers). This is why suppliers are required to keep the peroxide value below 20 mmol.

Positive reactions in people being investigated for eczema vary:

It's worth skipping if you have a known fragrance allergy or a compromised barrier, but the risk is low for most people.

Older or long-opened products are also more likely to bother you than fresh ones due to oxidation.

Geraniol can be found in many essential oils including Rose Oil and Citronella Oil. The scent of Geraniol is often described as "rose-like". Many foods also contain Geraniol for fruit flavoring.

Geraniol can irritate the skin when exposed to air. However, irritation depends on the ability of geraniol to penetrate into the skin. In general, geraniol is not able to penetrate skin easily.

Geraniol is colorless and has low water-solubility. However, it is soluble in common organic solvents.

Like citronellol, it is a natural insect repellent.

2,6-Octadien-1-ol, 3,7-dimethyl-, (2E)-

The EU requires it to be named on the label above 0.001% in leave-on and 0.01% in rinse-off products.

Fresh linalool is a weak sensitizer but air exposure turns some of it into hydroperoxides, which are strong sensitizers. Those oxidation products are the actual allergy concern.

Patch-test clinics see positive reactions to linalool hydroperoxides in about 4% to 12% of dermatitis patients depending on country and test concentration.

Resassuringly, one analytical study found hydroperoxide levels in real fragranced products to be orders of magnitude below what induced sensitization in animal studies with no evidence of oxidation building up during normal storage.

The practical takeaway is that linalool is fine for most people but worth avoiding if you have a confirmed fragrance contact allergy or a badly compromised barrier.

Products stored a long time after opening are also the high-risk scenario since that is when oxidation happens.

The scent of linalool is described as floral, spicy tropical, and citrus-like.

Citronellol is a modified terpene. Terpenes are unsaturated hydrocarbons found in plants. They make up the primary part of essential oils.

Citronellol is not able to be absorbed into deeper layers of the skin. It has low permeability,

Citronellol is also a natural insect repellent.