All kinds of skin problems will cause a person's life caused by varying degrees of trouble, especially issues at face. No matter diseases or aging would cause mental pressure and the inconvenience in different ages.

Scar caused by acne is the most common skin issue amount young people. While acne recovering, due to the destruction of collagen forming fibrous tissue, and scars be left. Clinical treatments are facial laser, argon laser and carbon dioxide laser. With the combination of rejuvenation to accelerate growth of collagen when needed. According to journal articles, facial laser combined with Platelet-rich plasma is more curative than facial laser treatment alone and can significantly reduce side effects (Dermatol Surg. 2014 Feb;40(2):152-61).

Platelet has been valued in regeneration medicine due to its various growth factors with repairment, induction and promotion functions. Moreover, low risk of allergy for it is an autologous material. Platelet had been officially applied in orthopedics and more clinical studies in many other fields. Nowadays, preparation of PRP is by single-use centrifuge tube, patients have to go through blood collection process every time before therapy due to short shelf life of PRP. Meanwhile, amount of platelet in PRP would be different due to difference of individual, health condition and separation methods. Thus, leaving unknown of active principle and uncertainty of treatments.

In this trial, a patented technique of lyophilized PLT preparation method is applied, collect 250 c.c. of blood specimen by using blood bag, separate platelet in germ-free clean room, then lyophilize platelet to extend shelf life to at least three years after quantifying platelet amount. Therefore, treatment could be done after simple dissolution process of PLT leads to the convenience of multiple therapy lessons.

Inclusion Criteria:

- all subjects of acne scars are defined of grades 1, 2, and 3 [Goodman and Baron Grading scale] were enrolled in the study.

Exclusion Criteria:

• Exclusion criteria included treatment with any laser device treatment to the face within 1 month, use of systemic retinoids within 3 months, pregnancy or lactation, a history of hypertrophic scarring or keloids, cancer therapies, uncontrolled diabetes, chronic liver or kidney disease, cardiovascular disease or hematologic disorders. Subjects were requested to avoid using any topical products containing alpha-hydroxy acids and salicylic acid on the face during the study period.