Maybelline Baby Lips Balm Versus Burt's Bees Lip Balm

There's some lab work behind its reputation; in one study, it acted as an antioxidant and calmed inflammation in human immune cells. But it also killed skin cells (keratinocytes) in a dish.

It stopped damaging those cells and still reduced swelling in mice when the researchers wrapped it in tiny capsules to slow its release.

One study that is quoted out of context frequently: clove oil killed human skin and blood vessel cells at levels as low as 0.03%, and about 73% of that came down to eugenol. Keep in mind those were bare cells sitting in a dish with no skin barrier in the way (which is a lot harsher than what happens on your actual face).

On concentrations, it is restricted to 0.64% in leave-on products + body products, 0.21% in baby + lip products, 2.5% in fine fragrance and 4.9% in rinse-off. Real formulas usually land far below those caps.

Allergy is the actual story with this ingredient. It is one of the eight markers dermatologists use for allergy testing, and the EU requires it to be named on the label above 0.001% in leave-on and 0.01% in rinse-off products.

It is also a prohapten, meaning it needs enzymatic activation in skin to become allergenic, so sensitivity varies between people.

Rates are modest but not trivial: in a classic EECDRG multicentre study, 13 of about 1,300 patch-tested patients reacted to eugenol, and in eugenol-allergic subjects the lowest positive patch test concentration was 0.031%, with 56% reacting in a 21-day repeated open application test at 0.5% to 2.7%.

Normal use levels are generally fine if you are not already sensitized.

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)-

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.

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.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.