The need for sun protection is widely recognized, but applying sunscreen often presents a dilemma for those concerned about hair health. People worry about the greasy residue, chemical reactions, or discoloration that standard body sunscreen might inflict upon their hair. This concern involves distinguishing between applying sunscreen to the scalp, which is skin and needs protection, and applying it directly to the hair strands. Understanding the effects of sun exposure and different sunscreen formulations allows for informed choices that protect both the scalp and the integrity of the hair.
How UV Rays Harm Hair
Hair structure is primarily composed of keratin, a protein that provides strength and shape. Excessive sun exposure causes structural impairment to the hair shaft. Ultraviolet B (UVB) radiation degrades hair proteins, while Ultraviolet A (UVA) radiation is linked to color changes.
UV radiation penetrates the outer layer of the hair, the cuticle, and reaches the inner cortex where the protein structure resides. This absorption generates free radicals that damage the keratin matrix. The resulting photochemical impairment decreases the hair’s tensile strength, making it feel dry, brittle, and rough.
The degradation of hair pigment, or melanin, is another consequence of UV exposure. Melanin normally absorbs and filters UV rays, providing a natural defense. When UV rays break down this pigment, it results in the fading or alteration of natural hair color. This effect is pronounced in chemically treated or light-colored hair, which may experience rapid color fading or the development of unwanted brassy tones.
The sun’s rays also deplete the hair’s natural moisture content by disrupting the lipid layer that retains water. This process exacerbates dryness and brittleness, leading to a loss of luster and increased susceptibility to breakage and split ends.
Sunscreen Ingredients and Hair Damage
The primary concern with applying traditional body sunscreen to hair strands is the adverse effects of its ingredients. Chemical UV filters are designed to absorb into the skin, but on hair, they can cause noticeable residue and unwanted chemical reactions. This is true for ingredients like Avobenzone and Octocrylene.
Avobenzone, an effective UVA absorber, reacts when it contacts the keratin protein in hair, especially under UV light. This reaction is accelerated by chlorine in pool water or minerals like iron and copper in hard water. The resulting chemical process can lead to significant discoloration, often causing light-colored or blonde hair to develop brassy, orange, or pinkish tints.
Oxybenzone is another chemical filter that can react with chlorine to strip dye from color-treated hair, causing premature fading. The combination of these active ingredients, UV exposure, and environmental factors makes chemical staining highly probable. Avoiding sunscreens that contain these specific chemical filters is recommended for preserving hair color.
Physical sunscreens use mineral filters like Zinc Oxide and Titanium Dioxide. While beneficial for skin protection by reflecting UV rays, when applied to hair, they leave a thick, white, and dull residue. This residue coats the hair strands, making them appear lifeless and heavy, and is difficult to remove without specialized washing.
Many spray or mist sunscreens contain high concentrations of alcohol for fast drying. When these alcohol-based products land on the hair, the alcohol strips the cuticle of its natural oils. This action increases dryness, disrupts the hair’s moisture balance, and contributes to a rougher texture and greater potential for breakage.
Effective Strategies for Hair and Scalp Protection
The most effective method for protecting both hair and scalp is the use of physical barriers. Wearing a wide-brimmed hat, a scarf, or other head coverings provides immediate protection from the sun’s rays. Accessories with a high Ultraviolet Protection Factor (UPF) rating offer additional safety.
When physical barriers are not practical, product selection and application technique are important. Use sun protection products specifically designed for the hair and scalp, which are formulated to be lightweight and non-greasy. These products often come as mists, sprays, or powders that contain UV filters without heavy oils or damaging chemical ingredients.
For scalp protection, lightweight, non-greasy sprays or powder formulas are preferred, as the skin on the parting and hairline is vulnerable. Part the hair in sections and apply the product directly to the scalp, avoiding saturation of the hair strands. Reapplication every two hours is necessary, especially if swimming or sweating.
To prevent damaging chemical reactions, look for mineral-based sunscreens utilizing Zinc Oxide and Titanium Dioxide for the scalp and body. These formulas are less likely to interact with hair keratin or cause discoloration, particularly if they are Avobenzone-free. Securing hair while applying body sunscreen minimizes accidental transfer.
After sun exposure, removing product residue or buildup is necessary. Clarifying shampoos are effective for deep-cleaning the hair and scalp of sunscreens, chlorine, and mineral deposits. Using a sulfate-free clarifying option is suggested for color-treated hair to ensure effective cleansing without excessive color stripping.