## 1 Introduction  
Skin injuries are the most commonly found injury caused by blisters, burns, cuts, and ulcers of various severities [1]. If left untreated, any skin injury can interfere with its protective function and cause body tissues to be easily exposed to mechanical damages and microbial infections [2]. Other problems that may accompany wound healing are excessive healing, delayed wound healing, or lack of skin appendages [1]. Recently, the increasing demand for quality improvement of damaged skin has led to the shifting focus of wound repair to the restoration of anatomy and function of the skin [3]. Thus, identifying an effective approach to enhance the wound healing process is indispensable [1; 2; 3; 4].  
Traditionally, the main purpose of wound care is to obtain wound closure at the earliest time [1]. Nowadays, the use of stem cell-based regenerative therapy to renew physiological tissue and promote the regeneration of various types of wounds is increasingly popular [2; 5]. Mesenchymal stem cells (MSCs) have been reported to have therapeutic potential after skin injury and extensive proliferation and differentiation capacity that have the ability to suppress the stimulation of immune cells and participate in tissue repair and regeneration [5; 6; 7; 8]. MSC releases a combination of growth factors and cytokines, so-called secretome, which can be applied to the wound through a conditioned medium (CM) [5; 9; 10]. The cytokines and growth factors play a crucial role in activating and stimulating fibroblast proliferation during the wound healing process [11]. Previous studies have reported positive results of wound healing and skin repair by utilizing CM from cultured MSCs (MSC-CM) derived from different sources such as bone marrow mesenchymal stem cell (BM-MSC) [9; 12; 13], adipose stem cell [14; 15; 16], [PERSON]'s jelly-derived MSC [17], and human umbilical MSC [1]. Furthermore, numerous studies have proven that several kinds of drugs can be potentially used to promote cell growth and proliferation that is beneficial for wound healing and hair regeneration including UK5099 [18], sodium L-lactate (SLL) [19], lactate dehydrogenase-A (LDHA) [18], caffeine [20; 21], and caffe acid (CFA) [22].  
Related to MSC-CM, not only can it be used in the repair of skin defects or wounds, but it can also enhance hair regrowth through differentiation or release of growth factors [23; 24]. A study by [PERSON] et al. [25] revealed surprising hair growth at the wound site following wound healing after MSC-CM was injected subcutaneously around a full-thickness wound in mice. To date, available data regarding the use of MSC-CM for hair follicle regeneration as well as wound healing are still limited, especially when using human hair follicle mesenchymal stem cells (HFMSCs) as the main source. Even though HFMSCs have been shown to have potential in hair regrowth, further studies are required to identify culture conditions that trigger the hair stimulating factors that warrant this application. Thus, to elucidate the regenerative potential of MSC-CM, we investigated CM from the supernatant of cultured HFMSCs and evaluated their effects on wound closure and hair regeneration.