在人體貼膚測試前，先利用5位受測者做貼布測試合成酯濃度對於人體皮膚傷害的閾值，將30%、15%、7.5%和0%的十六酸異丙酯(Isopropyl Palmitate, 以下簡稱IPP)用礦物油稀釋，再將0.2g沾於貼布，且貼於上背部7天，並同時額外調配30%的IPP與3%的香桃木精油，觀察是否有抑制面皰的功效。結果可發現，在15%以下的濃度作用於皮膚時，皮膚所受到的發炎損傷較不明顯，故後續實驗的油脂濃度將會以15%來配方。
In this study, human skin was exposed to three kinds of vegetable oils and one kind of synthetic ester to emulsions for a long time to observe the changes in skin characterization. For understanding whether or not cosmetic formulations using natural vegetable oils and synthetic esters have distinct and immediate reactions to human skin and comedogenic. At the same time, use the myrtle essential oil to test whether it has a good inhibition of acne for human skin.
Prior to the human body patch test, 5 test subjects were used to test the synthetic ester concentration threshold for human skin damage. 30%, 15%, 7.5% and 0% of Isopropyl Palmitate was diluted with mineral oil, and then 0.2g was applied to the patch and attached to the upper back for 7 days. A portion of 3% of the essential oil was used to observe the effect of inhibiting of acne. As a result, it was found that when the concentration is less than 15% on the skin, the inflammatory lesions on the skin are less noticeable, so the lipid concentration in subsequent experiments will be formulated at 15%.
Because the skin of the subject will be strongly stimulated by the patch test, and this is not a normal way of using cosmetics, there may be differences in the use characteristics of the actual product, so the next step is to use a cotton pad with 2g reagent. Applied for 20 minutes daily for 14 consecutive days to upper back of volunteers, and observed changes in skin texture: surface sebum measurements, surface hydration measurements, skin color measurements and skin condition photos. The emulsion was prepared using 15% Isopropyl Palmitate and 3 vegetable oils: olive oil, grape seed oil, and macadamia oil. And the emulsion prepared from isopropyl palmitate was containing 1.5% myrtle essential oil. And use water in the blank group. Therefore, prepare six kinds of reagents for this experiment.
The results of the experiment showed that after 6 consecutive application of reagents for 20 minutes in 14 days, skin surface sebum content, surface hydrotion content, and changes in skin erythema and melanin were still not significantly changed. Photographs taken from zoom in skin can reveal that some areas have caused redness or slight inflammation, but no acne has been produced. And compare test groups with blank group there didn’t increase comedones with naked eyes.