About the author: John Su is an established skin care expert and aspiring dermatologist. He also runs a blog, The Triple Helix Liaison, dedicated to providing unbiased, meaningful, and insightful information about skin care. For his full bio, please visit our About page.
Fragrances are to topical products, as computers are to the world: they are everywhere. I’d imagine that I’d be difficult to compile a list of people who completely ignore computers. Like so, one has to scour the market to find products that are truly fragrance-free. But should the average consumer be wary of fragrances in skin care?
The Typical Response to Fragrance
The most common responses to fragrances manifest as mild forms of allergic reactions ranging from dermatitis to hives. Anaphylaxis is rarely seen. Therefore, while the dangers of having an allergic reaction to fragrances are low, studies indicate that a significant margin of the general population is at risk (estimated to be 1%) (1). That was from a study done in 1997, and given the upward trend of allergic reactions and autoimmune diseases seen in subjects of civilized nations, that number is likely even higher (estimated to be 1.7%-4.1% in 2003) (2). In case you’ve lived in another dimension for the past few years, it’s 2012.
Different Types of Fragrances
Now, there are three main groups of fragrances: Fragrance Mix I, II, and the Others. Note that these groups are categorized by time of discovery, rather than structural similarities.
- Fragrance Mix I (FM I) includes, from most likely to least likely to trigger a reaction: oak moss, isoeugenol, eugenol, cinnamic aldehyde, geraniol, hydroxycitronellal, cinnamic alcohol, and Alpha-amyl cinnamic aldehyde. These were introduced in 1977 and have been acknowledged and accepted by the community at large (3).
- Fragrance Mix II (FM II) includes, (in the same order as FM I): Lyral, citral, farnesol, coumarin, citronellol, and Alpha-hexyl cinnamal. These were introduced in 2002 after the compounds found in FM I only accounted for approximately 70% of the symptoms reported by those known to have fragrance allergies (4).
- The Others (which is just an arbitrary name that I made up) consists of 26 total fragrances (including some of those found in FM I and II) that have been further identified and analyzed, resulting in regulatory actions pertaining to package labeling. I won’t list them all because that would take forever, but some commonly used ones include: benzoyl alcohol, limonene, and linalool. The seventh mandate of the EU Cosmetic Directive(March 2005) legally requires that all cosmetic products sold in Europe containing any of these 26 fragrances at concentrations > 10 ppm for leave-on products, and > 100 ppm in rinse-off products (5), must be included in ingredient lists.
I’m obviously not going profile each ingredient and analyze them because again, that would take forever and a day.
Take Away Notes
So what’s the most important thing to take away from all this technical terminology?
- If you’re prone to allergic reactions to fragrances, now you know that there are lists of well-documented compounds to watch out for when shopping for skin care. You won’t have to go through that annoying and even painful trial-and-error stage.
- But keep in mind that just because you don’t see a fragrance listed on the packaging, doesn’t mean that one or more aren’t present at concentrations < 10 ppm or < 100 ppm respectively, for leave-on or rinse-off products.
After reading this, if you’re thinking that from now on, you’re only going to use fragrance-free products, consider the flip side:
Studies indicate that a few commonly-used fragrances are some of most gentle and effective penetration enhancers available on the market (6). The cited study (6) indicates that limonene has the highest ER/IP ratio (ER/IP = 22.32/5.92 = 3.77; rank 1) of the 102 chemical penetration enhancers tested. ER stands for Enhancement Ratio and that was measured by stratum corneum disruption and therefore, permeability enhancement (7). IP stands for Irritation Potential, which was measured by estimating cell viability of normal human-derived epidermal keratinocytes in a methyl thiazol tetrazolium (MTT) assay, using Epiderm, which is described in the same study (7).
In layman’s terms, MTT assays measure the activities of specific enzymes, many of which are found in living human skin cells. Unfortunately both linalool (ER/IP = 24.52/50.63 = .484; rank 72) and geraniol (ER/IP = 32.74/47.53 = .689; rank 53), which are even more commonly used than limonene; don’t fare nearly as well. So take that with a grain of salt. Limonene is excellent, while others are not so much. Note that menthol, a commonly used compound known for its minty smell and “tingly” sensation, has a rank of 99. But I’ll be going into detail about this specific ingredient next week because it’s so widely used and misunderstood.
Finally, consider this last concept as you deliberate over fragrances in skin care. Certain fragrances like lavender, which relies primarily on linalool, has been known to induce feelings of relaxation (8). While I don’t believe that aromatherapy has any tangible or measurable benefit for the skin, if a certain scent can help you relax, that’s good news!
From numerous posts on FutureDerm and many medical studies, stress is not good for your skin. If you can relieve some of that stress with a refreshing lavender-scented moisturizer, go for it!
With everything in mind, I think it’s safe to say that:
- If you are prone to allergic reactions, use FM I, II, and the Others to avoid such reactions. Furthermore, those who are not prone to allergic reactions, but would still like to avoid fragrances, can do the same.
- If you are not prone to allergic reactions, and believe that fragrances help enrich your life through either penetration enhancement or olfactory bliss, fragrances may be a positive characteristic in your skin care routine.
Now I know I’m going to be asked what my personal choice on this matter is, so I’ll just jump the gun: Unless it’s limonene, I avoid all fragrances in my skin care because they bother my sense of smell, and because they have no real benefit. I do enjoy fragrances however. But I rely on things like Bath & Body Works candles to create that “ambience of serenity.” Did I actually type that?!
If you have any questions, please post either down below in the comments section, or on my blog. Stay tuned for next week as we unravel menthol and its derivatives!
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