Clinical efficacy of intradermal type I collagen injections in treating skin photoaging in patients from high-altitude areas

Table 1 Inclusion and exclusion criteria

Inclusion criteria	Exclusion criteria
Age ≥ 18 yr, male or female	Pregnancy or lactation
Glogau photoaging score of II or III	Systemic diseases, such as diabetes, autoimmune diseases, and severe heart, liver, and kidney dysfunction
Residing in areas with an altitude of ≥ 1800 m for > 10 yr	Current treatment with glucocorticoids, estrogen, and other drugs that may cause facial pigmentation and affect the experimental results
Voluntarily receiving intradermal injection of Sunmax Col for facial rejuvenation and signing informed consent forms	Facial laser, freezing, and other treatments within the past 3 months
	Facial filling or botulinum toxin injection within the past 6 months
	Known allergies to Col or other ingredients in Sunmax Col
	Failure to follow up as planned or data loss affecting the evaluation of efficacy