MC1R rs1805008: What Your Genotype Means
The rs1805008 variant is a well-studied genetic change in the MC1R gene that is strongly associated with red hair, fair skin, and freckling. It is one of several variants that influence how the body produces pigment, contributing to the characteristic appearance of redheads.
What each genotype means
Typical pigmentation profile
This genotype does not carry the R160W red-hair variant. Individuals with this profile typically exhibit standard pigmentation patterns associated with their ancestry.
This is the most common genotype in most global populations.
Carrier of red-hair variant
You carry one copy of the R160W variant, which is associated with red hair and fair skin. Carriers may be more likely to experience freckling and increased sun sensitivity compared to those without the variant.
This genotype is found at varying frequencies in European populations and is less common in other global populations.
Likely red hair and fair skin
You carry two copies of the R160W variant, which is strongly associated with red hair and fair skin. This variant contributes to the MC1R loss-of-function phenotype, often resulting in increased sun sensitivity and a higher likelihood of freckling.
This genotype is relatively rare and is primarily observed in individuals of European ancestry.
Understanding the rs1805008 Variant
The rs1805008 variant, often referred to in scientific literature as R160W or Arg160Trp, is a single nucleotide polymorphism (SNP) located on chromosome 16 within the MC1R gene. In this specific location, a change in the DNA sequence results in an amino acid substitution in the protein produced by the gene. This variant is categorized as a trait-associated SNP, meaning it is statistically linked to observable physical characteristics rather than being a direct cause of a specific disease. Because it is located in a gene critical for pigmentation, researchers have extensively studied how this specific change alters the function of the melanocortin 1 receptor. It is considered a 'red hair color' (RHC) variant, and its presence is a key indicator used in genetic studies to understand the biological pathways that determine human hair and skin color diversity across different populations.
The Role of the MC1R Gene
The MC1R gene provides instructions for making the melanocortin 1 receptor, a protein found on the surface of melanocytes. These cells are responsible for producing melanin, the pigment that gives color to our skin, hair, and eyes. The receptor acts like a switch; when activated by specific hormones, it triggers the production of eumelanin, which is a dark, protective pigment. When the MC1R gene carries variants like rs1805008, the receptor's ability to signal for eumelanin production is often reduced. Instead, the cells produce more pheomelanin, a lighter, reddish-yellow pigment that provides less protection against ultraviolet (UV) radiation. This shift in pigment production is the primary reason why individuals with these variants often have lighter skin, a reduced ability to tan, and a higher sensitivity to sun exposure, which is why they are frequently studied in the context of skin health.
Research and Evidence Strength
The evidence linking rs1805008 to red hair and fair skin is considered strong and has been replicated across multiple studies, particularly in European populations such as those in Ireland, the Netherlands, and Iceland. Research indicates that this variant, along with others in the MC1R gene, contributes to the 'red hair phenotype' by impairing the receptor's signaling function. Beyond pigmentation, the variant is also associated with an increased risk of skin cancers, including melanoma, due to the decreased production of protective eumelanin. While the association with red hair is robust, it is important to note that MC1R is not the only gene involved in pigmentation; other genes also contribute to the final appearance of an individual. Furthermore, while some studies have explored potential links between MC1R variants and pain sensitivity or opioid response, these findings are complex and require further investigation to fully understand the clinical implications.
What This Information Means for You
Knowing your genotype for rs1805008 can provide insight into why you may have certain physical traits, such as red hair or fair skin that burns easily. However, it is important to remember that genetic variants are only one piece of the puzzle. While this variant is associated with a higher sensitivity to sun exposure, it does not mean that an individual will definitely develop skin cancer or any other condition. If you are concerned about your skin health or sun sensitivity, the most effective approach is to practice consistent sun protection, such as using sunscreen and wearing protective clothing, regardless of your genetic profile. If you have questions about how your genetics might influence your health or your response to specific medications, you should discuss these topics with a qualified healthcare provider or a genetic counselor who can provide personalized guidance based on your full medical history.
How common is this variant?
The rs1805008 variant is most commonly observed in populations of European descent, where it is a well-documented contributor to red hair and fair skin phenotypes.
Frequently asked questions
Does having the rs1805008 variant mean I will have red hair?
While rs1805008 is strongly associated with red hair, it is not the only factor. Other genetic variants in MC1R and other genes also play a role, so having the variant does not guarantee a specific hair color.
Is rs1805008 a cause of skin cancer?
The variant is associated with an increased risk of skin cancer because it affects the production of protective pigment. However, it is a risk factor, not a direct cause, and environmental factors like sun exposure are significant contributors.
Can I use this information to change my medication dosage?
No. You should never change your medication dosage based on genetic information alone. Always consult with your doctor or pharmacist before making any changes to your prescribed treatments.
Are there other genes that affect hair color?
Yes, human pigmentation is a complex trait influenced by many genes, including OCA2 and others. MC1R is a major contributor, but it works in concert with a broader genetic network.
Sources & further reading
Educational information only, last refreshed 10/5/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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The p.Arg163Gln variant in MC1R is associated with red hair, fair skin, and increased melanoma risk.
This missense variant (p.Arg160Trp) is a primary genetic determinant of red hair color, pale skin, and increased freckling in European populations.
This missense variant (p.Arg142His) is a well-established, highly penetrant allele associated with red hair color and fair skin pigmentation.
The Val60Leu missense variant in MC1R is a well-documented factor contributing to the red hair, fair skin, and freckling phenotype.
A rare variant associated with lighter skin pigmentation in specific populations.
Asp294His coding substitution in the MC1R gene associated with red hair, skin sun-sensitivity, and melanoma risk.