Still Don’t Make Your Own Sunscreen But….. A Closer Look at Raspberry Seed Oil
In December 2012 I wrote a little article advising people not to make their own Zinc based sunscreen. That post still attracts lots of eyeballs and comments which is interesting and why I’m following it up with another post. I’m happy to say that I have dissuaded some people from making and selling their own zinc sunscreen either because they didn’t realise the testing costs involved or that actually there is more to this than just adding zinc into a cream and hoping for the best but I haven’t put everyone off. Some of those enthusiastic people feel that there is always the potential for a stone I’ve left unturned (maybe there is) or a solution I didn’t spot (again, possible) but to date I’m yet to read a comment that has me going ‘aha, they are onto something’ and the zinc-only products on the market are still largely as they were when I wrote this – a mixture of not-that-great to quite nice and wearable but not as invisible or flexible as some other options out there.
But that’s not what I’m wanting to talk about here, here I want to talk about Raspberry Seed Oil.
So while some ‘make your own sunscreen’ enthusiasts are off playing with zinc, others are out picking raspberries……
It has been said, once or twice on the great Googlesphere that Raspberry Seed Oil is a fab natural sunscreen. Now while there is some scientific basis behind that statement a sunscreen it is not and I think it’s time I explained why in the best way I can and for me that means starting with the science of what we know and what we don’t.
Scientific Study: Characteristics of Raspberry Seed Oil, B Dave Oomah, Stephanie Ladet, David V Godfrey, Jun Liang, Benoit Girard. Food Research Programme Canada Published in Food Chemistry issue 69, 2000, page 187-193.
Finding: Raspberry Seed Oil showed good absorbance in the UVB – UVC ranges with potential for use as a broad spectrum UV protectant.
NOTE: The oil extracted for this test was done so using hexane, a food-grade solvent.
Snipped of the above paper talking about Sun Protection.
I don’t want to be the biggest party pooper on the planet but WHAT ARE THEY TALKING ABOUT HERE?
Crude Raspberry Seed Oil showed some absorbance in the UVC and UVB range.
OK so UVC is is not a concern for the skin as it is filtered by the ozone layer whereas UVB and UVA are as they are the more energetic ‘skin damaging’ rays – well, damaging if you get too much. Therefore I’ll ignore the UVC bit.
UVB is interesting though but how did they test this? I’m suspecting it was using a labsphere machine because of how the data is presented. Labsphere machines can give a theoretical SPF/ result to make sure a product is safe to then start using on real people, they are often used in sunscreen testing for that purpose and to give an idea of where testing should start (what SPF).
I’m feeling OK about this until I see the next sentence: In the UVB range, Raspberry Seed Oil can shield against UVA induced damage by scattering as well as by absorption.
What? How can they now jump to what the oil will do in the UVA region when they are not measuring it? What do they mean by shielding against damage by scattering and absorption I wonder? These terms are simple enough – scattering light is what Titanium Dioxide and Zinc Oxide do – they bounce it away from the skin so the energy doesn’t get in and burn us. Absorption is also easy, that’s what chemical sunscreens do, they interact with UV rays and chemically disable it by reducing its energy. I can’t accept that Raspberry Seed Oil can do either without evidence and I see no evidence here.
With regards to results for UVB that’s fine but if you shield the skin from UVB without considering UVA you actually leave the skin in a situation that is worse than if you used nothing. Our skin has evolved with the UVA and UVB in proportion, not one or the other. To treat the UV spectrum as a set of boxes that you can either take or leave is to not understand how it works, it is a continuum, a spectrum and rather than chopping it up one needs to just dim it evenly like you would dim the lights in a room.
Ok but then we have another sentence that in light of the above makes me even more confused:
The optical transmission of Raspberry Seed Oil, especially in the UV range (290-400nm) was comparable to that of titanium dioxide preparations with sun protection factors for UVB and UVA between 28-50 and 6.5-7.5 respectively.
That sentence above has been enough to have a whole barrel load of people think that Raspberry Seed oil has an SPF of up to 50. I would hesitate to get so excited and this is why.
- I can see no evidence that this test was validated on people – what something appears to do on a labsphere machine may not happen in-vivo. It would make sense to test this on people and I have seen that happen with far lower results than these ( A potential SPF boost of between 4-5 possibly).
- Again the UVA and UVB are separated which makes no sense when we are looking to apply this to real life. It is a falsehood to think that human SPF testing ONLY focuses on UVB, the human SPF testing exposes people to a simulated sunshine which includes UVA as well as UVB. While we can induce the sunburn with just UVB whereas UVA doesn’t do that to think that an SPF is ONLY UVB is outdated for the reasons I stated before. The red reaction is what we measure because it is the first visual sign that the skin is in trauma and that trauma is a signal for both UVA and UVB, the body doesn’t care to assign such arbitrary limits.
- Titanium Dioxide at what concentration and particle size? The way this is written shows a lack of understanding for how sunscreen actives are sold. It would make more sense to report an approximate SPF range per unit used. Titanium Dioxide generally gives around 2 and up to 2.5 ish SPF units per 1%. Zinc Oxide is somewhere in the region of 1-1.5. We are none the wiser as to the concentration of Raspberry seed oil needed to get this amazing result OR do we just assume we put it on neat?
- Neat oil is a possibility but what about the lens effect of the oil film? Oils that leave the skin shiny can actually accentuate the suns rays thus making it more likely rather than less to burn. It is likely that this physical phenomena would reduce the SPF potential of this oil somewhat, especially if one needs to apply it neat to get a result.
- The UV spectra range of Titanium Dioxide is only broad spectrum if the particle size is small (towards nano) and even then it doesn’t have the broad UVA coverage that Zinc does so will this Raspberry Oil leave us wanting in the high frequency UVA range?
Let’s have a closer look at the graphs:
At the bottom of these it does say that the Raspberry Seed Oil was diluted to 1%
And here are some typical absorbance curves.
We are focusing on the Absorbance as that’s what matters. To be like Titanium Dioxide we would want to see absorbance above 1 in the 290-340 wavelength. What we do see is weird. The top graph only goes up to a wavelength of 290, anything before that is kind of irrelevant as we only start counting UVB from 280. At 280 the Absorbance is looking to be somewhere around 0.2 which is not really that good. Absorbance usually ranges from 0-2. O = no absorption and 2= 99% absorption. So if we just extrapolate that and say, for argument’s sake that an Absorbance of 1 = 50:50 (1/2 of rays are absorbed), 0.5 = 1/4 of rays absorbed and 0.25 = 1.8th of rays absorbed or 12.5% so more is getting through than being mopped up or diverted.
We have to come down to the second graph to get the interesting data but suddenly the Raspberry seed oil has jumped from absorbing only 0.2 at 290nm to absorbing nearly 0.9 at 290nm – how can this even happen? It then drops off reaching around 0.1 absorbance at the 350 wavelength which means that even if we can trust these numbers it is running well short of being broad spectrum.
Then on the last graph we again see what looks like a miraculous jump from an absorbance of close to 0 at 400 wavelength to an absorbance of………less than 0.1 – yes, they changed the gradient to make it look more exciting maybe or maybe just so we can zero in on how not good this is at protecting from these high wavelengths.
By contrast we see the graph below. We can see that Titanium Dioxide does quite a good job in the UVB region (280-320) absorbing in the 1.2 region (60% absorbed) but by the time it gets to 400 we only have about 0.3 or 15% absorbed, 75% getting through.
So what’s the verdict?
If I had to base my sunscreen formulations on this one paper I’d not be relying on Raspberry Seed Oil. The study has some deficits that make me wonder if the people involved had much experience in sunscreen development – why should they after all, they are publishing in a food journal about a food by-product.
But I don’t just read journals I also do lab stuff.
I have seen raspberry seed oil in action and being tested in sunscreen formulations and in the tests I’ve seen it might add a bit of a boost to the SPF – in the order of 4-5 SPF units for a product containing between 1-5%. Aha, I hear you say, but what about a product with JUST Raspberry seed oil???? Based on the above I’d not rely on the Raspberry seed oil to give me anything like the broad spectrum protection that Zinc Oxide or smaller particulate Titanium Dioxide can give so no, I don’t see that as an option.
But what we haven’t talked about is the oils antioxidant content. Quite a few fruit oils do contain antioxidant chemicals which can help mop up the damage that excessive UV radiation can leave behind. Dousing the skin with antioxidants every day sounds like a very good idea to me and could strengthen the skin making it less likely to succumb to UV induced damage. However, this mopping up doesn’t mean the skin hasn’t been exposed. One would have to weigh up the benefit of having a good cleaner in a house full of slobs. Sure the cleaner will work like mad but if there are too many slobs in the house the cleaner will get tired and die of exhaustion, your antioxidants are no different.
My advice to those looking to substitute ‘chemical’ sunscreens with antioxidant rich oils and extracts is yes, do it but also do yourself a favour and modify your sun behaviour too so that you are at least giving your antioxidants a fighting chance of keeping up.
I see no reason for these antioxidant rich oils to not be part of a natural approach to sun protection and for some people it may indeed be enough, but for everyone else I’m still going to be advising some good old-fashioned ‘chemical’ sunscreen.