Evaluation of skin irritation and hypoallergenic potential of Venusia Cleanser using the human repeat insult patch test

INTRODUCTION

The skin barrier serves as the body’s primary defense against environmental insults, pathogens, and chemical irritants, yet it remains vulnerable to disruption through daily exposures and improper skincare practices. Facial skin faces constant challenge from cosmetics, pollutants, and ultraviolet (UV) radiation, making it especially susceptible to irritation and sensitization reactions. Skin irritation, characterized by inflammation, erythema, and compromised barrier function, affects a substantial portion of the population, with studies indicating that up to 50% of individuals report experiencing sensitive skin at some point in their lives.^[1,2]

Among the various products used on facial skin, cleansers play a critical role in dermatological care. Although they are crucial for eliminating dirt, sebum, and potential irritants, they can also compromise the stratum corneum’s integrity and trigger inflammatory cascades.^[3,4] Using harsh or inappropriate cleansers can remove natural lipids, disrupt the skin’s natural moisturizing factor, and disturb the delicate pH balance essential for maintaining an effective barrier.^[5] As a result, cleansers must be formulated with mild, hypoallergenic ingredients to minimize the risk of irritation and adverse reactions. Dermatologists are increasingly advising the use of cleansers and moisturizers that are not only gentle and dermatologically approved but also particularly appropriate for sensitive skin.^[6,7] Sensitive skin is a clinical condition characterized by the self-reported sensory symptoms that include tightness, stinging, burning, tingling, pain, and pruritus.^[1] Such heightened cutaneous reactivity necessitates the use of well-tolerated skincare products that minimize irritation. This, in turn, enhances patient adherence and consequently improves patient outcomes, as people will be more inclined to stick to regular skincare routines when the products are well-tolerated and do not cause adverse effects.^[8]

Given the significant proportion of the population affected by skin sensitivity and the recognized need for gentle yet effective cleansing solutions, rigorous evaluation of new formulations is essential. The present study aims to evaluate the skin irritation and hypoallergenic (skin sensitization) potential of Venusia Cleanser by employing standardized dermatological testing methods.

MATERIALS AND METHODS

RESULTS

A total of 220 participants were recruited, of whom 218 participants completed the study. Two participants were lost to follow-up.

Challenge phase

Challenge phase reactions were scored using the ICDRG scale [Table 6]. No strong positive reactions (++) or higher were observed at any time point for Venusia Cleanser. A few (n = 38, 17%) participants showed doubtful and weak-positive reactions at 48 h, which were resolved by 72 and 96 h, indicating transient and mild skin responses. The challenge phase thus demonstrated no meaningful sensitization.

Table 6: Scores for the challenge phase for the test product and saline.

Reaction category	48 h (n=218 participants)	72 h (n=218 participants)	96 h (n=218 participants)
0.9% Isotonic saline solution	218 had negative reactions	218 had negative reactions	218 had negative reactions
Venusia Cleanser
Negative reaction (–)	180	217	218
Doubtful reaction (?)	37	1	0
Weak positive (+)	1	0	0
Strong positive (++)	0	0	0
Extreme positive (+++)	0	0	0
Irritant (Ir)	0	0	0

Representative HRIPT images from participants with normal skin [Figure 1] and sensitive skin [Figure 2] show no visible reactions for Venusia Cleanser versus negative control during induction (patch application at visit 1 and scoring after 9^th application) and challenge (application and 96-h scoring) phases. Images were captured only for reactions with Grade ++ or higher.

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Figure 1:

Representative human repeat insult patch test images on normal skin showing no irritation or sensitization from Venusia Cleanser versus negative control during induction (9^th application) and challenge (96 h score) phases.

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Figure 2:

Representative human repeat insult patch test images on sensitive skin showing no irritation or sensitization from Venusia Cleanser versus negative control during induction (9^th application) and challenge (96 h score) phases.

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DISCUSSION

This study demonstrates that Venusia Cleanser is non-irritant even after nine induction applications and a challenge exposure and is hypoallergenic, with no strong positive skin reactions or adverse events observed. This suggests that there is no significant sensitization potential in a diverse population, including individuals with sensitive skin. The mean cumulative irritation score of 0.08 recorded for Venusia Cleanser during the induction phase was significantly below the non-irritant threshold of 2.0, as specified by the BIS - IS 4011: 2018 Methods of Test for Safety Evaluation of Cosmetics (Third Revision) guidelines. This suggests that repeated occlusive application of the cleanser did not result in clinically significant irritation.

The non-irritant profile of Venusia Cleanser is particularly important for patients with sensitive skin, who constituted 36% of the study cohort. Sensitive skin poses distinct challenges due to complex interactions between climate, lifestyle, and traditional skincare practices.^[6] Dermatologists and cosmetic scientists define “sensitive skin” as skin that is more prone to contact irritants or allergic reactions compared to the general population.^[17] In an Indian survey involving 3012 participants, 27.9% of men and 36.7% of women reported having “sensitive” or “very sensitive” skin.^[18] The underlying causes of sensitive skin are not well understood and may involve neurosensory dysfunction or a compromised skin barrier.^[19]

The lactic acid sting test in this study identifies sensitive skin through a rigorous methodological approach to selecting at-risk individuals.^[9] Lactic acid sting test identifies those with compromised skin barriers rather than relying on self-reporting alone. By ensuring the study included participants who were identified as having sensitive skin through this validated test, the design provided the framework to confirm that the test product does not compromise barrier function in individuals with this pre-existing vulnerability.

Ensuring that facial cleansers are hypoallergenic is an essential safety feature, as cosmetics and personal care items are increasingly identified as significant triggers of allergic contact dermatitis. Common cosmetic allergens include fragrances, preservatives, and certain surfactants, which can cause delayed-type (type IV) hypersensitivity reactions, particularly in people with sensitive or compromised skin. Therefore, cosmetic products designed for dry sensitive skin should be subjected to thorough testing to confirm their hypoallergenic properties.^[6]

The assessment of potential sensitization through the HRIPT is an important component of this study’s safety evaluation. Unlike irritant contact dermatitis, which occurs on first exposure and is dose-dependent, allergic contact dermatitis develops only in individuals who have been previously sensitized.^[20] The HRIPT is considered the gold-standard clinical method for evaluating sensitization potential^[21] because it encompasses the two critical stages necessary for the development of allergic contact dermatitis: The induction phase (where the immune system becomes sensitized to potential allergens through repeated exposure) and the challenge phase (where sensitized individuals exhibit visible allergic reactions upon re-exposure). In this study, the absence of strong positive reactions to Venusia Cleanser at any assessment timepoint, combined with the rapid resolution of minor doubtful and weak-positive reactions observed in 38 participants at 48 h, strongly indicates that the cleanser does not contain significant sensitizing agents.

Venusia Cleanser contains several complementary ingredients that together promote gentle cleansing, barrier repair, and anti-inflammatory benefits. Sodium cocoyl isethionate, a syndet surfactant, is notably gentler on the skin barrier compared to traditional soaps. An in vitro study has demonstrated that its relatively large micelles have limited penetration into the skin’s aqueous pores, leading to less barrier disruption and irritation.^[22] Allantoin exhibits antioxidant, anti-inflammatory, antimicrobial, and keratolytic properties, aiding the transition of skin from a prolonged inflammatory state to the proliferative phase by promoting extracellular matrix synthesis, granulation tissue formation, and re-epithelialization.^[23] Niacinamide has been clinically proven to enhance barrier function, reduce transepidermal water loss, increase stratum corneum hydration, and decrease inflammation and hyperpigmentation, making it suitable for sensitive and diseased skin.^[24] Panthenol (provitamin B5) improves hydration, supports barrier lipid synthesis, and accelerates recovery of irritated skin. It also shows protective effects against experimentally induced irritation; dexpanthenol cream pretreatment significantly reduces stratum corneum barrier damage compared to untreated skin.^[25] Colloidal oatmeal extract provides antioxidant and anti-inflammatory activity and has demonstrated significant reductions in erythema, itch, and xerosis in patients with eczematous and dry skin.^[26] Finally, topical formulations containing ceramides and HA improve water retention and restore barrier function by replenishing intercellular lipids and binding water within the stratum corneum, which is clinically associated with improved hydration and reduced dryness.^[27]

From a clinical and patient-centered perspective, the daily use of a hypoallergenic, non-irritant facial cleanser is crucial for maintaining skin homeostasis and preventing dermatological complications in real-world settings. Regular cleansing effectively removes excess sebum, environmental pollutants, particulate matter, and residual makeup, thereby reducing the risk of follicular occlusion and subsequent inflammatory conditions such as acne vulgaris.^[17] This practice is particularly relevant in urban environments where exposure to atmospheric pollutants contributes to oxidative stress and accelerated skin aging.^[28] The hypoallergenic and non-irritant formulation minimizes the potential for contact sensitization or exacerbation of sensitive skin conditions, thus encouraging long-term adherence to a cleansing regimen without causing the barrier disruption or dryness often associated with harsher surfactants.^[3]

The present study has several strengths. It used a standardized HRIPT methodology under stringent exposure conditions with evaluator blinding and a negative control. This enhances internal validity and supports robust assessment of the irritation and sensitization potential of the product. The inclusion of participants with sensitive skin, as determined by the lactic acid sting test, further enhances the clinical applicability of the results for real-world users who may be more susceptible to skin reactions.

CONCLUSION

Under HRIPT conditions, Venusia Cleanser exhibited a mean cumulative irritation score well below 2, with no strong positive reactions, no signs of clinically significant sensitization, and no adverse events throughout the study. This evidence supports classifying Venusia Cleanser as a non-irritant, hypoallergenic cleanser suitable for repeated use, even for individuals with sensitive skin.