Skip to the end if you are just interested in DIY sunscreen
Sunburn is best avoided; it isn't pretty and it hurts. No one is going to argue with that. Yet, far too many people treat high SPF sunscreen as the first, best, and only line of defence. The heavy slopping of SPF50+s is fuelled by the potential risks of skin cancer. However, as the Environmental Working Group (EWG) points out, the relationship between sunscreen and cancer prevention is tenuous at best.
I realise that statement’s a little controversial, considering WHO’s recommendation (Australian and New Zealand recommendations are similar) to slop on a thick layer of SPF50+ before you venture outside. However, there are a couple of points to consider before you write off this blog as the ramblings of a mad person.
While vitamin D is available from fortified foods (many cereals), and plant sources such as mushrooms (especially when exposed to sunlight), the best natural source of vitamin D (specifically vitamin D3 cholecalciferol) is the Sun! The liberal use of sunscreen prevents the synthesis of vitamin D via the skin.
As Faurschou et al notes “When the amount of sunscreen and SPF advised by the World Health Organization are used, vitamin D production may be abolished. Re-evaluation of sun-protection strategies could be warranted.”  Further, in an Australian study of “patients presenting with fractures” a “prevalence of vitamin D insufficiency and deficiency was common” .
Sure, you can get your vitamin D via supplements but, perhaps, the fear of UV rays also needs dialing back a peg or two.
High SPF sunscreens contain chemical ingredients, many of which carry potential health risks. Two common sunscreen ingredients are Oxybenzone and Octinoxate which may cause hormone disruption; both are rated as serious hazards on the EWG database. Many of these chemicals also cause bleaching in coral. So, if you’re environmentally friendly you might want to rethink using high SPF sunscreen. (Damaging coral and the life systems it supports isn’t the vegan way either).
Broad band protection (the UVA/UVB spectrum)
High SPF sunscreens will, well should, at least if used correctly, prevent sunburn. But that’s not the whole picture. While they protect the user from UVB rays they may not offer protection from “UVA rays, which produce subtler skin damages” (EWG)
EWG’s Sunscreen Guide
I could go on for ages but why reinvent the wheel? EWG have already produced an excellent (and very lengthy) reference guide that covers every aspect of the use and pitfalls, the facts and fallacies, the best and the worst of sunscreens. ‘A Decade of Progress, but Safety and Marketing Concerns Remain’
So… what’s the option?
The Herb Solutions mantra is (wherever possible) “natural, organic, and cruelty free”. From that starting point the only option is a mineral sunscreen. [See 'all natural oils' below] Mineral “Sunscreens using zinc oxide … tend to rate well in our analysis: They are stable in sunlight, offer a good balance between protection from the two types of ultraviolet radiation (UVA and UVB) and don’t often contain potentially harmful additives.” EWG
Zinc oxide does occur naturally (zincite) but is more commonly produced synthetically. It is considered safe, with an EWG hazard rating of 2 (with less than 0.01% skin penetration), “is stable in sunlight and can provide greater protection from UVA rays than titanium oxide or any other sunscreen chemical approved in the U.S.” (Schlossman 2005).
It’s not perfect. There are some serious concerns around nanoparticles of zinc or titanium entering the environment and, indeed, there’s now an entire field of study on nanotoxicology. A partial answer is to move to non-nano zinc (and just put up with a slight whitening of the skin when the cream is applied).
All natural coconut oils (and similar)
While we would wish it otherwise, natural oils are not suitable as standalone sunblocks.
Although you’ll see oils rated anywhere between SPF1 and 15, these are based on in-vitro tests and don't equate to actual skin protection. Coconut oil’s in-vitro test gives an SPF = 7 but, when applied to skin as the only form of protection, its SPF may be little more than 1 (e.g. no protection at all).
Secondly, natural oils don’t provide a suitable broad band protection against UVA and UVB rays. That said, they do make an excellent base for a moisturising sunscreen.
The next best thing: DIY sunscreen.
A very quick and easy DIY sunscreen solution is:
Herb Solutions Kawakawa infused ‘Summer Sun Cream’
For the more adventurous. DIY plus.
Want to go a bit further and make the moisturiser from scratch? Herb Solutions’ preferred recipe is:
If you prefer (and we do) you can infuse the coconut oil prior to making the cream. In the Herb Solutions ‘Summer Sun Cream’ we infused the oil for 72 hours with Kawakawa (a traditional cure for many skin conditions including sunburn).
Then add the shea butter and jojoba oil, followed by the vitamin E. Finally, add the zinc oxide to convert the moisturising cream to a sunscreen. Mix well, cool, and bottle.
How Much Zinc Oxide?
The quantity of zinc oxide depends on the SPF required (approximately). For example, if you have 100g of cream add 5% non-nano zinc oxide to give an SPF of somewhere between 2 and 5.
We don’t recommend going higher than 20%, bearing in mind that the base cream will also slightly increase the SPF.
SPFs - A Final Word.
Just in case you didn’t know, an SPF (Sun Protection Factor) relates roughly to the time you can spend in the sun before getting burned. So (very roughly), if you would burn in 10 minutes (without sunscreen) then applying an SPF 20 sunscreen would let you stay in the sun for 200 minutes (10 x 20). Of course it depends what you are doing, and that's not a number you would want to push to the limit (the degree of protection will reduce over time).
For the more tech-minded: SPF15 blocks around 94% of UVB rays and SPF30 blocks around 97%. The number doubles (SPF15 to 30) as the percentage of UVB that reaches the skin is halved (from 6% to 3%). But REMEMBER, the measure only relates to UVB and sunburn. High SPF sunscreens do not neccessarily block any UVA rays, and it’s these rays that can cause deeper skin damage.
The final final word? Be informed. Don’t rely on marketing claims (or this blog, or the neighbour's cat).
Before heading out this summer do a little research into what you’re slopping onto your largest organ!
 Faurschou, A., Beyer, D.M., Schmedes, A., Bogh, M.K., Philipsen, P.A. and Wulf, H.C. (2012), The relation between sunscreen layer thickness and vitamin D production after ultraviolet B exposure: a randomized clinical trial. British Journal of Dermatology, 167: 391–395. doi:10.1111/j.1365-2133.2012.11004.x
 Mow, T. C., Stokes, C. M. and Sutherland, A. G. (2015), Patients presenting with fractures are likely to be vitamin D deficient: are we getting enough sun?. ANZ J Surg, 85: 766–769. doi:10.1111/ans.13190