What Are Freckles and Why Do We Get Them?

Freckles are small, sun-responsive pigment spots that appear on the skin, especially in people who are genetically prone to them. While they’re very common and harmless, many people wonder why they show up on their skin in the first place and some are curious about ways to get them to fade. Here, we take a deep dive into the science behind what a freckle is, what causes them, and what you can do to minimize their appearance if you prefer. 

Freckles, also called ephelides, are small, flat spots that develop when the skin produces more melanin, the pigment that gives skin its color. They are essentially areas where melanin has been turned “up,” often due to a genetic predisposition combined with sun exposure. 

This happens because the melanocytes in freckle-prone individuals respond differently to UV radiation. When UV light reaches the skin, it triggers a signaling pathway that activates melanocyte-stimulating hormone (MSH). MSH binds to the MC1R receptor on melanocytes, essentially telling them to “turn on” pigment production. In people with certain MC1R gene variants, this pathway works differently, causing melanocytes to produce pigment in small concentrated spots instead of evenly tanning the skin.

A few key points that make freckles unique:

• They are caused by pigment overproduction, not cell overgrowth. Freckles are clusters of melanin, not clusters of melanocytes like with moles.

• They darken and fade seasonally. Because freckles depend on UV-triggered melanin production, they typically appear darker in summer and lighter or nearly invisible in winter.

• They form in the epidermis. Freckles are superficial, meaning they don’t extend into deeper skin layers, which is why they’re flat and often easier to lighten compared to moles, which are often deeper.

Freckles form when the melanocytes in the skin increase melanin production in response to UV radiation, particularly UVB. In people who are genetically predisposed, UV light triggers melanocyte-stimulating hormone (MSH), which signals melanocytes to deposit extra melanin into surrounding skin cells, called keratinocytes. This causes the darker, more visible spots on the surface of the skin that we know as freckles.

Factors that contribute to freckles include:

• Genetics: People with specific versions of the MC1R gene are more prone to freckling.

• Fair skin: Less melanin means the skin responds to UV by producing pigment in small concentrated areas.

• Sun exposure: UV exposure is the primary trigger for freckles to appear and darken.

• Hormones: Although less influential than with moles, hormonal shifts can sometimes change how melanocytes respond to UV.

• Age: Freckles are most prominent in childhood and adolescence when melanocytes are more active.

There are two main types of freckles that are influenced by sun exposure:

• Ephelides. These are the classic freckles that most people think of. Ephelides typically appear in childhood and are associated with MC1R gene variants. This type of freckle will darken in the summer and fade in the winter.
• Solar lentigines, or “sun spots.” These dark spots develop later in life as a result of years of accumulated UV exposure and do not fade in the winter. They are often larger and more defined than ephelides. 

While anyone can develop freckles, they’re much more common in people with a particular genetic profile such as that seen in red heads.

The MC1R gene influences how melanocytes produce pigment. There are two main types of melanin:

• Eumelanin: Brown/black pigment that protects skin

• Pheomelanin: Red/yellow pigment that offers less UV protection

People with certain MC1R variants (especially “R” variants like R151C, R160W, or D294H) produce more pheomelanin. This leads to:

• Red or strawberry-blonde hair

• Fair skin

• Increased sun sensitivity

• A higher likelihood of freckling

This is why redheads and people with fair skin develop freckles more easily. However, freckles can also appear in people without these gene variants, especially those with lighter skin tones.

Freckles are usually light to medium brown in color but can also be reddish. They are usually small, 1 to 5 mm in diameter, and are round with smooth, well-defined edges. True freckles are flat and not raised and will darken with sun exposure. 

Moles, on the other hand, can be raised or flat and can appear at any age. Similarly, sun spots can also appear at any age and tend to be larger than freckles and will not fade in the winter.

No, freckles themselves are not harmful and do not turn into skin cancer. However, people who freckle easily often have fair skin, UV sensitivity and a higher lifetime risk of sun damage. This means that freckles are a reminder that your skin needs consistent sun protection year-round.

Melanoma, which is a deadly form of skin cancer if not caught early, can look like a freckle.  Any new freckles- especially those that are dark brown, blue or black and asymmetrical should be evaluated by a dermatologist ASAP.

Redheads should have a full body skin exam at least once a year and more often if you have had significant sun exposure or you have many freckles.  Some high risk redheads should get checked every 3 months.

Freckles cannot be removed permanently because they are caused by a genetic response to UV light. However, skin-lightening ingredients can help to make them lighter and less noticeable. 

Topical ingredients that can help to fade freckles include:

• Vitamin C, which inhibits tyrosinase, the enzyme that drives melanin production.

• Azelaic acid, which reduces pigment and evens tone.

• Niacinamide, which slows melanin transfer from melanocytes to skin cells.

• Retinoids, which increase cell turnover and help to fade pigmentation.

• Kojic acid, another tyrosinase inhibitor that’s effective for sun-induced spots like freckles.

In-office treatments like lasers, chemical peels, and microneedling may also help to minimize the appearance of freckles. However, freckles often return with sun exposure because the underlying genetics that cause them don’t change.

Genetics determine your tendency to freckle, but sun exposure determines whether freckles appear or darken. So while you can’t change your MC1R gene, you can take steps to reduce UV-triggered freckling, such as:

• Wearing daily SPF.

• Reapplying SPF at least every 2 hours when outdoors.

• Avoiding tanning beds and deliberate tanning outdoors.

• Using antioxidants like vitamin C to help prevent pigment formation.

Freckles are small spots on the skin that darken with sun exposure and are driven by genetics and UV exposure. They’re harmless, common, and more likely to appear in people with MC1R variants, particularly redheads and those with fair skin. While freckles can fade with sun protection and skin-brightening ingredients, they’ll return with UV exposure because the underlying genetics remain the same. 

The best approach is embracing them if you love them and protecting your skin if you prefer them lighter.

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