Do Self-Selected Fragranced Products Preserve an Individual Scent?

Do differences between people’s odors remain when they use fragranced deodorant? In a 2015 study, people could distinguish individuals’ odors better than chance overall, both without a product and when fragranced products were used. Samples collected with donors’ usual, self-selected products were also easier to distinguish than samples collected with products assigned by the researchers.

However, the no-product condition was the easiest to distinguish overall. This is not a simple story in which a self-selected scent invariably enhances someone’s individuality. The study examined differences between people when body odor and fragranced products are combined.

Comparing odors from people who use the same product

The odor donors were six men and six women. All were nonsmokers who regularly used deodorant, and the women used hormonal contraception. All the men normally used the same commercially available body spray. The women were selected in three pairs, with each pair using the same one of three antiperspirant deodorants.

There was a reason for this arrangement. If everyone used completely different fragrances, participants might simply identify different products rather than different people’s odors. Comparing people who used the same product reduced this problem.

On three consecutive days, donors washed with fragrance-free soap and then wore cotton pads in their armpits for 24 hours. On day one they used no deodorant, on day two their usual product, and on day three a previously unused product assigned by the researchers. They applied their usual amount and were instructed to avoid other fragranced products, strong-smelling foods, alcohol, exercise, and similar sources of interference.

The assigned product was the same body spray for all men and the same antiperspirant deodorant for all women. This was not a test of adding fragrance alone, but a comparison of real products that also contained odor-suppressing ingredients and, in the women’s products, sweat-suppressing ingredients.

Which of three samples comes from a different person?

The raters were 427 visitors to a science center in the United Kingdom: 296 women and 131 men. Of these, 238 smelled samples from male donors, while a separate group of 189 smelled samples from female donors.

In each task, two samples from one person and one sample from another were presented in flasks, and participants selected the odd one out. Within each task, all donors were of the same sex and all samples came from the same product condition. The chance success rate was about 33%.

Each rater completed one task in each of the three conditions: no product, the usual product, and the assigned product. Different donor pairs were used for each condition, and the pairings and conditions were rotated across testing sessions. Participants also completed a 12-item test in which they identified familiar odors by choosing among four names.

Overall, usual products allowed better discrimination than assigned products

Pooling everyone’s results, correct responses were significantly above the 33% chance level in all three conditions. Thus, in these samples, cues that distinguished individuals were not completely lost after fragranced products were used.

In an analysis including age, rater and donor sex, odor-identification scores, and other factors, correct responses were more likely with no product than in the two fragranced conditions combined. They were also more likely with the usual product than with the assigned product.

The authors interpreted this as suggesting that a person’s chosen fragrance combined with their body odor may preserve individual differences better than a combination assigned by someone else. However, the overall findings did not support the initial possibility that adding fragrance would make individual differences stand out more than they did without a product.

Male and female samples did not follow the same pattern

Importantly, this overall picture did not apply unchanged to every combination. Female donors’ samples were easier to distinguish without a product, and accuracy fell with fragranced products. Looking specifically at the difference between the usual and assigned products for female samples, there was no clear statistically significant difference.

For male donors’ samples, pooling all raters showed above-chance discrimination in all three conditions, with no clear differences between conditions. When the results were further divided by rater sex, some combinations did not exceed chance. For example, male raters correctly identified the odd sample only 30% of the time when smelling female samples with the assigned product.

These differences cannot be explained solely by biological sex differences. Men and women used different products, including differences in antiperspirant action, and differed in how they managed their underarm hair. Fragrance and body-odor intensity were not measured. Whether male samples were stronger and more distinctive, or whether product differences mattered, remained questions the authors identified for further study.

The smeller’s identification ability also mattered

People who scored higher on the familiar-odor identification test were more likely to answer the body-odor triangle test correctly. Across all conditions, accuracy was 57% among female raters and 48% among male raters, and the analysis also found higher performance among women.

Age itself was not clearly associated with triangle-test performance in the analysis that included the other factors. However, older age was associated with lower scores on the odor-naming test. This does not mean that age has no relationship with olfaction; rather, performance on this task needs to be considered alongside identification ability.

How people choose a personally fitting scent remains unclear

Although there were many raters, there were only six odor donors of each sex. The product order was also fixed: none, usual product, then assigned product. The study did not standardize product ingredients and application amounts to compare fragrance alone. These points matter when trying to explain why usual products performed better.

The authors described the findings as supporting the possibility that fragrance preferences reflect compatibility with one’s own body odor. However, the study tested discrimination between samples from different people. Whether attractiveness, emotions, health status, or genetic characteristics can still be accurately inferred after fragrance is added requires separate investigation.

Summary

Even with fragranced deodorant, individual odors could be distinguished better than chance overall. Samples without a product were the easiest to distinguish; among fragranced samples, correct responses were more likely with donors’ usual, self-selected products than with researcher-assigned products.

However, condition differences varied according to donor sex. Both the combination of body odor and product and the smeller’s ability were related to how individual odor differences were perceived. The experiment illustrates the value of studying these combinations, rather than fragrance or body odor alone.

The paper reports Czech Science Foundation support for one author, and the authors declare no conflicts of interest.

References

Allen C, Havlíček J, Roberts SC. Effect of fragrance use on discrimination of individual body odor. Frontiers in Psychology. 2015;6:1115. doi:10.3389/fpsyg.2015.01115