Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Bachelor of Science in Nursing

Degree Level

Undergraduate

Department

Nursing

Advisor/Mentor

Alyssa Parsley

Committee Member

Kristina Simpkins-Spain

Abstract

Background: Genetic variations of the melanocortin-1 receptor (MC1R) are commonly associated with red hair and pale skin. Research has linked MC1R variants with alterations in anesthetic response, pain perception, opioid sensitivity, and pain-related fear. Existing literature presents inconclusive findings, highlighting the need for further investigation.

Purpose: This review aims to synthesize current evidence concerning the role of MC1R variants in altering physiologic responses.

Methods: A systematic literature review was conducted by accessing CINAHL, MEDLINE, and PubMed through the University of Arkansas Libraries OneSearch platform. After applying inclusion and exclusion criteria, a total of 20 peer-reviewed articles were extracted for review.

Results: Studies related to anesthesia requirements were generally inconsistent, with early evidence suggesting increased anesthetic needs in redheads, while larger studies found no clinically significant differences. Opioid analgesia studies had more consistent findings, displaying enhanced analgesic effects, particularly in females taking k-opioids. Overall pain perception results were contradictory, with reports of both increased and decreased sensitivity. Research on pain-related fear consistently indicated high levels of anxiety and fear of pain among individuals with MC1R variants and red hair.

Conclusions: Current evidence does not support changes in clinical practice based on hair color alone. It is possible that MC1R variants may contribute to altered physiologic responses, but findings remain conflicting. Further research is necessary, with an emphasis on genetic analysis, larger sample sizes, and replication of assessment methods. Until more definitive evidence is available, clinical nursing practices should place a focus on individualized assessments and awareness of the potential for altered responses in red-haired patients.

Keywords

red hair; mc1r; anesthesia; pain; redheads; hair color

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