Skin cancer rates are increasing around the world, especially in countries with strong sunlight like Australia. This has made sun protection more important than ever. One of the best ways to prevent skin cancer is by using broad-spectrum sunscreens that are approved by trusted health authorities such as Australia's Therapeutic Goods Administration (TGA). These sunscreens are tested to ensure that they provide strong and reliable protection against harmful ultraviolet (UV) rays.

However, some people are concerned about the long-term effects of chemical ingredients found in commercial sunscreens. They also worry about the impact these chemicals might have on the environment. As a result, many people have turned to homemade sunscreens using natural oils and zinc oxide. These products are often promoted by wellness blogs and DIY skin care communities as being safer and more environmentally friendly. But how well do they actually protect the skin?

A recent scientific study investigated this question by comparing the effectiveness of a popular natural homemade sunscreen with a well-known commercial SPF 50+ sunscreen. The goal was to understand whether the natural option could truly provide adequate protection from UV damage.

What Was Tested?

The researchers tested three different skin treatments on human skin samples:
1. A homemade natural sunscreen (NHSS), based on a recipe found online.
2. A commercial SPF 50+ sunscreen (Banana Boat Dry Balance).
3. A control base lotion without active ingredients.

The homemade recipe contained a mix of natural oils and zinc oxide powder, which is a known physical UV blocker. The oils used included almond oil, coconut oil, shea butter, beeswax, red raspberry seed oil, and carrot seed oil. This combination is often shared online and promoted for its claimed natural SPF properties.

How the Study Was Conducted

Skin samples were taken from donors with very fair skin (Fitzpatrick skin type I), which is most vulnerable to UV damage. Each skin sample was treated with one of the three preparations and then exposed to ultraviolet radiation in a controlled lab setting. After exposure, the researchers analyzed the samples for four key indicators of skin damage:
- Cyclobutane pyrimidine dimers (CPDs): signs of direct DNA damage caused by UVB rays.
- 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OXO): markers of oxidative DNA damage, often linked to UVA rays.
- Sunburn cells: damaged skin cells undergoing programmed cell death.
- Epidermal thickness: an increase in skin thickness is a typical biological response to UV stress.

Study Results

DNA Damage

The commercial SPF 50+ sunscreen provided strong protection against both CPDs and 8-OXO, showing levels of DNA damage similar to unexposed control skin. This confirmed that it effectively blocked both UVB and UVA radiation.

The homemade natural sunscreen (NHSS) showed some protection—it reduced DNA damage when compared to the base lotion—but not nearly as much as the commercial product. CPDs and 8-OXO levels were significantly higher in the NHSS group than in the SPF 50+ group.

Sunburn Cells

The number of sunburn cells in the NHSS-treated skin was almost the same as in the base lotion, indicating poor protection. In contrast, the commercial SPF 50+ sunscreen drastically reduced the number of sunburn cells, further demonstrating its effectiveness.

Epidermal Thickening

Skin samples exposed to UV without effective protection showed noticeable thickening of the outer skin layer. This is a normal stress response. The NHSS offered some reduction in thickening compared to the control, but not as much as the SPF 50+ sunscreen. Again, the commercial product was superior in preventing this marker of UV damage.

Why Did the Homemade Sunscreen Perform Poorly?

The NHSS contained zinc oxide, which is known for its ability to reflect and scatter UV rays. However, in a homemade mixture, it is hard to guarantee the correct amount of zinc oxide is used or that it is properly dispersed throughout the lotion. This leads to inconsistent coverage and uneven protection.

The plant oils in the recipe—though nourishing for the skin—do not offer significant UV protection on their own. Many studies have shown that these oils have very low SPF values, typically between 1 and 5, far below what is needed for meaningful sun protection.

Furthermore, DIY formulations lack the rigorous testing and stability checks that commercial sunscreens undergo. This makes it difficult to assess whether the final product is safe or effective when used in real-life conditions, such as during swimming or sweating.

What Does This Mean for Everyday Sunscreen Use?

The homemade sunscreen offered partial protection. It was better than nothing in reducing DNA damage and skin thickening. However, it failed to prevent sunburn cells, which are a direct sign of skin injury. This makes the product unreliable for full UV protection.

The commercial SPF 50+ sunscreen, on the other hand, consistently protected the skin from all forms of UV-related damage in the study. Until more research and formulation improvements are made, homemade sunscreens cannot be recommended as safe alternatives to regulated products.

Key Takeaways

- Commercial sunscreens offer complete protection against DNA damage and cell death caused by UV radiation.
- Homemade sunscreens may offer limited protection but are inconsistent and generally not strong enough.
- The safety and effectiveness of DIY sunscreens are untested and should not be relied on.
- Always use certified, broad-spectrum SPF 30+ or higher sunscreens, especially during long sun exposure.
- Further research is needed to make natural sunscreens safer and more reliable.

Conclusion

Protecting your skin from the sun is essential to prevent damage and reduce your risk of skin cancer. This study showed that while homemade natural sunscreens can reduce some forms of UV damage, they do not offer the same level of protection as commercial products. In particular, they fail to prevent the formation of sunburn cells, a clear sign that the skin is still being harmed.

Until natural sunscreens can be tested, certified, and proven to be as effective as commercial ones, it is safest to rely on products that are approved by regulatory agencies. These products undergo thorough testing to ensure they provide the broad-spectrum protection your skin needs. Natural ingredients may have a future in sun protection, but more research and development are needed to make them both safe and effective.

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