Introduction This document is a clinical trial protocol. This research will be conducted based on the standards of the Good Clinical Trial Method and regulations from the relevant institutions and ethics committees.

Background Acne vulgaris (AV) is a chronic inflammatory disease with multifactorial causes in the skin's pilosebaceous follicular units, with clinical manifestations in the form of comedones, papules, pustules, nodes, and pseudocysts. The following factors are considered important for the etiology of AV: increased rate of sebum excretion, endocrinological factors such as androgens, abnormal keratinization of the follicular infundibulum, the proliferation of Cutibacterium acnes (C. acnes), and inflammation. Recent studies at the molecular and cellular levels have clarified how these factors interact and the role of the innate immune system. Inflammatory processes have been demonstrated in all types of lesions - preclinical microcomedones, comedones, inflammatory lesions, 'post inflammatory' erythema or hyperpigmentation, and scarring. Inflammation localized to the pilosebaceous can be considered a hallmark of acne and should be managed through several therapeutic routes. Clinicians tend to think that oral antibiotics should be used to treat inflammation in acne. However, this treatment are associated with resistance and low outcome due to its adverse events such as erythema, desquamation, and dry skin. There is evidence of the use and opportunity of vitamin D as a novelty treatment influencing the immune system. 25OHD and 1,25(OH)2D are both catabolized by CYP24A1. 1,25(OH)2D is a ligand for the vitamin D receptor (VDR), a transcription factor that binds to sites in DNA called vitamin D response elements (VDRE). Thousands of these binding sites regulate hundreds of genes through several signaling pathways in different cell types, including their regulation in immune cells by toll-like receptors (TLRs), the primary signaling nucleus of C. acnes that interacts with the innate immune system, causing acute and chronic inflammation.

Study Objectives Primary Objective The primary objective of this study is to evaluate the efficacy and safety of combination topical vitamin D and supplementation as adjuvant therapy in acne vulgaris compared to placebo and topical vitamin D monotherapy.

Secondary Objective(s) To assess Vitamin D Receptor (VDR) expression on acne lesion and blood sample To assess the effect of combination topical vitamin D and supplementation on IL-1β expression on acne lesion To assess the effect of combination topical vitamin D and supplementation on IL-6 expression on acne lesion To assess the effect of combination topical vitamin D and supplementation on IL-10 expression on acne lesion To assess the effect of combination topical vitamin D and supplementation on IL-17 expression on acne lesion

Inclusion Criteria:

• Men and women diagnosed with moderate or severe acne vulgaris
• Aged over 18-50 years.
• During the study, were willing not to use skin care products either in oral and/or topical form on the face, as well as other treatments outside of standard AV treatment.
• Willing to take part in the examination and treatment in accordance with the provisions of the study and follow the control time schedule in accordance with the predetermined research plan also willing to sign the informed consent form.

Exclusion Criteria:

• Women who are pregnant and breastfeeding.
• Have history using topical antibiotics in the past 2 weeks.
• Have history using topical corticosteroids in the past 2 weeks.
• Have history taking vitamin D supplements in the last 1 month.
• Have history taking oral antibiotics in the last 1 month.
• Have history using oral corticosteroid use in the last 1 month.
• Have history using oral and topical retinoid use in the last 3 months.
• Have history using topical BPO in the last 1 month.
• Using hormonal contraception for women.
• Have history of drug allergies or skin disorders due to side effects of first-line therapy drugs for moderate/severe acne vulgaris.
• Impaired liver and kidney function.