In a typical lab you don’t often get much time to just play around. But you snatch the odd moment to indulge yourself from time to time, and I always enjoy spreading the emollient oils on my skin to get to know their individual characters and personalities. One long standing favourite is isopropyl myristate which has a soft silky feeling, a bit reminiscent of velvet.
It gets used quite often in skin creams, particularly premium high quality ones. I have to say that if I am honest I have never really felt that it actually contributes as much to these formulations as it promises to from how it feels neat. Where it really scores is in bath oil formulations. I am a busy man and I usually take a shower to save time, but every now and again I’ll enjoy a bath with a bath oil rich in isopropyl myristate.
Chemically speaking it is a branched ester. All this means is that the molecule is made up of chains that branch out and that it has a particular kind of chemical link called an ester link. There is a whole family of branched esters, notably isopropyl palmitate which is similar to isopropyl myristate and which some formulators prefer. I like them both and I particularly like having a choice. Sometimes you see formulations where quite a few branched esters have been used. In this case it is probable that somebody somewhere has gone to a lot of trouble blending different oils to get exactly the skin feel that they wanted.
Isopropyl myristate also has a further use. It is a handy solvent for removing prosthetics, particularly latex based ones. So if you are in films and have to restore a horde of zombies to human appearance before they go home, it is the go to material. It is a lot easier than pulling off the latex and risking tearing the skin. You don’t want them ending up looking like actual zombies.
Isopropyl myristate is perfectly safe as a cosmetic ingredient and there are no issues with it as far as end users are concerned. It has been attacked by scaremongers either from ignorance or more likely from a cynical desire to sell inferior products at high prices. Any website that suggests this material is harmful should be ignored.
There is one persistent story that keeps coming up, and that is that isopropyl myristate is comedogenic. This issue dates back decades and should have been cleared up years ago. Comedogenic is an ugly word and I would be a lot happier if we used plain english. If you are suggesting that something causes blackheads, it is a lot easier to understand if you just say so. But back to my story. During the sixties several labs worked to try and use tests done on animals to help study skin diseases. This blog is about science not ethics so I won’t comment on the rights or wrongs of the morality. But it has to be said that the science wasn’t great. Rabbit ears were the focus of the study, but for what it showed they might as well have left the rabbits in peace. The problem was that there was very poor agreement between labs even on the results of the tests let alone the interpretation of them. Isopropyl myristate was shown by some labs to be comedogenic to rabbits ears. Others got the opposite. And as to whether this meant that it would cause comedogens in humans, well that was far from clear either. It turned into one of those areas of research where the more papers you read the less you understood what was going on. What I can say is that I have had plenty of isopropyl myristate on my skin over the years and it has never given me a single blackhead.
So all in all, a lovely raw material.
I am doing quite a few ingredient posts at the moment. You might find this one on potassium sorbate interesting. It is a preservative often used in natural products.
You can find the official information about isopropyl myristate at cosmetics.info.org
Yay! Another great and enlightening article! I’ve become an addict of your blog, Colin, and I’m not afraid to admit it! 🙂
This is a great blog Colin.
I was wondering if you can tell me a bit about benzyl alcohol. I am trying to make a face cream for sensitive skin and have come across a preservative – a combination of benzyl alcohol and dehydoacetic acid. What do you think. I notice you havent written much about it here.
Thanks in advance.
@Lise – thank you. You are making me blush.
@Rebecca – Benzyl alcohol and dehydroacetic acid are both good enough for people with sensitive skin in my opinion. But the ideal choice has to be some combination of the parabens if you want to absolutely minimise the risk of skin reactions. There are, of course, other considerations when making your selection.
But surely the scientists must have used rabbit ears in the first place because they were supposedly a good enough model for human skin 😛
Great blog by the way – an informed opinion is fantastic, with all these confusing claims out there in the market!
THANK YOU! THANK YOU! THANK YOU!
I stumbled across yuor excellent blog and will be back to read more! Such well written and interesting articles with a dash of humour and all written in plain English. What a breath of fresh air. The “thank you” is especially for enlightening me about isopropyl myristate, the main ingredient in my “dermaologist’s recommendation” in my fight against eczema. I had been having a few doubts, mainly brought about by scare-mongerers online, but after an hour’s reading of your blog, I feel confident I can trust your opinion. (How do you DO that??!)
Keep up the good work.
Thank you Ruth. Feedback is always welcome, especially when it is so positive.
Hi Colin,
The blog about isopropyl myristate is really useful. If I wish to make a dispersing bath oil, about what percentage of isopropyl myristate and laureth-4 do you advise me to use in combination with sweet almond oil? Thanks in advance.
Hello Olu, thanks for your kind words. I am not sure exactly what kind of product you are aiming for, so you’ll have to do your own experiments. I’d start at about 5 percent of the surfactant, and maybe 20 percent of the IPM. But you have plenty of work ahead to get to something good.
As to how much is the percentage for isopropyl meristate in any formulation? And which do u prefer emulsifying wax or cytearyl alcohol?
Hello Jo, how much IPM is used varies enormously and I don’t have any particular preference.
Some said it should be 4 percent but others said you can use it up to 50 percent. But thanks anyways
I’ve seen higher and lower than those numbers. But as your question was its use level in any formulation that is quite a wide scope.
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