Here’s a new video on why DIY sunscreen doesn’t work. It’s a much more detailed version of my post on DIY sunscreen from a while ago. It’s a topic that’s quite important to me, since it’s one of those cases where having the wrong information can cause serious harm!
This video has been a bit delayed due to the rest of my life getting a bit hectic, but I managed to get it out before the Northern Hemisphere summer finished, so go me…
I bought a lapel microphone and some new editing software, so everything is a bit more polished I hope! Check it out here.
Extra notes and references
Since I know there are a lot of nerds out there who like references and extra information, here are some of the sources for specific things I mention in the video (I got lazy with my citation style, sorry):
Skin cancer stats are sourced from the Cancer Council Australia and the Skin Cancer Foundation, who list the original sources at the bottom of their respective sites.
SPF testing guidelines: FDA (USA), TGA (Australia), EC (EU).
Dangers of UVA: Blog Post: Why You Should Protect Yourself From UVA
More info on sunscreen formulation
- SQ Wang & HL Lim (eds), Principles and Practice of Photoprotection: A very comprehensive book on everything related to sunscreen. Part II has a few chapters on sunscreen formulation.
- Realize Beauty, The Trouble With Making Your Own Sunscreen: Amanda Foxon-Hill, a cosmetic chemist, talks about the difficulties she encountered when trying to formulate a sunscreen. Her other posts are also very interesting!
- Kobo Products, Perspectives on Supplying Attenuation Grades (presentation): Info on zinc oxide photoreactivity and surface coatings, particle size and aggregation vs protection.
- BASF Creations Newsletter, Formulating with Zinc Oxide: Lots of information on how to formulate sunscreens with zinc oxide, including some information on dispersion and pH.
- Silverson, Manufacture of Suntan Creams and Lotions: Tips on dispersion from the manufacturer of some of the best industrial homogenisers used in sunscreen manufacture.
Sunscreens are very unlikely to cause endocrine disruption in practice: Journal of the American Academy of Dermatology (open access – quote: “Mathematic modeling indicated that it would take 277 years using a sunscreen containing 6% oxybenzone used at 2 mg/cm2 (the dose recommended for sun-protection factor [SPF] testing by the FDA) or 1 mg/cm2 (reported real-life use) to achieve the systemic levels of oxybenzone achieved in the study in rats”), Australasian Journal of Dermatology (looks at other filters apart from oxybenzone)
Nanoparticles in sunscreens are safe: TGA Literature Review (very comprehensive)
More (open access!) papers on zinc oxide: Nanotechnology Science and Applications, Science and Technology of Advanced Materials
People stay in the sun for longer when wearing sunscreen: JID paper (open access)
Reporting illegal medicines: FDA report form, TGA report form
Do oils increase UV penetration?
This is a topic that I thought deserved a longer write-up.