The Secret Life of Germs: an experiment in diluting shampoo
Natural products are often expensive, and as such many people try to stretch them and get the most out of their purchases. This is understandable, but when it comes to safe usage and formulation, things can get a bit tricky.
If we’re talking about adding more fixed oils to other anhydrous products (products not containing water) then go crazy! In fact, I recommend it. Essential oils (EOs) are best diluted in a fixed oil (coconut, almond, grapeseed etc) for safe use on skin. But if we’re getting into hydrous products, the plot thickens.
A common product I see people diluting is natural shampoo. Young Living’s shampoo is incredibly thick - almost like syrup. Between that and the cost, diluting it into multiple bottles is a very attractive notion, and is often promoted by users and reps.
After studying formulation for a few years, I’ve discouraged this as a rep myself. The product is not labeled for or intended for diluting. The preservation system in it is not meant to accommodate additional added water.
Preservation systems are highly specific in their formulation. They are used at precise amounts to hit a target percentage within the overall product volume, must be compatible with other ingredients, and must work within the pH of the product. If we take an 8 oz bottle of shampoo and dilute it with 50% water to make two 8 oz bottles, we have just cut the overall preservative percentage in half, and likely skewed the pH closer to 7. If a preservative is tested and proven effective at a recommended usage of say, 1%, how can we expect it to perform as well at 0.5%?
(Hint: we can’t, and it won’t.)
Now, this is not an issue with products intended to be diluted, like cleaner concentrates. Thieves Household Cleaner is meant to be diluted in up to 30 parts water. As such, the preservative content within it is appropriate to handle that level of dilution and still keep the product stable.
So I’ve been seeing all these posts with people diluting the shampoo, thinking it was a bad idea, discouraging anyone who asked me from doing it, but didn’t have any concrete proof that my concerns were accurate beyond what I’ve learned about appropriate formulation in my research.
…until now. *Cue the ominous music*
Here’s the methodology of how my experiment went down.
I bought a bottle of Young Living’s Lavender Mint shampoo. (It’s delightful! I’d highly recommend it, and even my husband is a fan. He isn’t always a lover of my natural products, but this was a winner.) I started the experiment within a week of receiving the bottle (this shouldn’t matter as unopened it will be stable for quite some time, but I wanted to have as fresh a product as possible.)
I set out to prepare 4 different scenarios.
1) The original shampoo, undiluted, in the original bottle.
2) The original shampoo, undiluted, in another, travel-size bottle (this was in case there was an issue with bacteria introduced during the transfer even without the presence of additional water. In general this should not be an issue with such products, but I wanted to cover all variables.)
3) The original shampoo, diluted 50% (half distilled water, half shampoo), in another, travel-sized bottle
4) The original shampoo, diluted 75% (25% distilled water, 75% shampoo), in another, travel-sized bottle (most of the posts suggesting diluting this product recommend 50%, but I was curious if diluting it less would make a difference.)
All of the travel-sized bottles were new, and first sanitized with 70% isopropyl alcohol (IPA). I pour enough in to swirl around the entire inside, squirt some through the mouth of the bottle, and spray the outside surface with the IPA. These were then left to dry on a clean paper towel, covered with another clean paper towel. I do this for all my DIY projects and highly recommend it to anyone formulating at home. You will never have a totally sterile production space in a home environment, but 70% IPA kills a LOT. It is actually more effective than stronger alcohol blends, as they coagulate the proteins on germ surfaces so badly the alcohol can’t fully penetrate into the cell, whereas 70% allows for full penetration and destruction of the unwanted organism. You can read more about that here if you’re interested.
…also, who read the word “penetration” and DIDN’T giggle? You are a stronger adult than I!
For the water, I used distilled water (from a new, unopened bottle purchased from the grocery store) that was then heated to boiling in a glass Pyrex measuring cup in the microwave (the Pyrex got the 70% IPA treatment too), and let it cool to be still hot/warm but not boiling when added to the shampoo. (I did this because this is how I most frequently see people suggest diluting the product. I’m honestly not sure what the purpose is of heating the distilled water first, but just following the protocols I see so many reps advocate.)
Once the blends were created (and the undiluted shampoo was transferred into the travel-size bottle) I put all four samples into our showers (two in each shower.) They were used for two weeks, during which time they were stored with lids tightly on and closed when not in use, lids down to prevent any additional water from entering, and in a spot with good drainage on a hanging rack so they were not sitting in puddles.
After the two weeks, swabs were taken of all bottles by moistening a sterile swab in distilled water, dipping it once into the shampoo itself, and then applying that swab to a pre-filled agar petri dish in the recommended star pattern. The agar dishes were labeled, taped shut, and incubated for the recommended 48-36 hrs.
I don’t have an incubator so for me this consists of strategically placing them near the stove when it’s on (and convincing my husband it’s totally fine to eat dinner that was prepared next to a veritable hot zone) or treating them to a romantic snuggle by the fire, checking them for the optimal range of 85-100 degrees F.
One night we cuddled together fireside and watched Mr. and Mrs. Smith on tv. I think I heard the germs whisper as they grew “…poor Jen Aniston didn’t stand a chance.” Word, little germs.
And thus, Brangelina was born… and some microbial colonies of unmentionable horror.
Without further ado, here are the results:
1) The original shampoo, undiluted, in the original bottle: No growths detected. Clean as a whistle!
2) The original shampoo, undiluted, in another, travel-size bottle: No growths detected. Thank goodness, because my husband was using this one. He would have been less than pleased if I had encouraged him to use a product that turned out to be a cesspool of nastiness!
3) The original shampoo, diluted 50% (half distilled water, half shampoo), in another, travel-sized bottle: Oh, my friends. Things have gone awry in this bottle. It’s not good. It’s really, really not good.
I normally try to give a count of the growths for comparison, but I can’t. There are hundreds if not thousands. Every single spot I swabbed is littered with colonies of… something. This is not what I’d want to be rubbing into my scalp and allowing to rinse down my face and body.
Since we had a tender moment the night before watching the movie, I shared with these germs my dismay that my favorite rosé wine from the vineyard owned by Brangelina doesn’t seem to be distributed anymore, perhaps due to their divorce. The germs were very sympathetic, as they too know how hard it is to find an exceptional rosé.
4) The original shampoo, diluted 75% (25% distilled water, 75% shampoo), in another, travel-sized bottle: If you think adding less water is the answer, you are mistaken. This one is as bad as the 50% bottle. Colonies as far as the eye can see. Bad news, my friends.
I heard these germs muttering about my artichoke stuffing technique from when they observed my cooking in their spot stove top. Yeah, yeah, I’m no Julia Child. But they conceded it’s curious any human ever thought to attempt eating an artichoke in the first place, being as stabby as they are.
The outcome is exactly what I expected to happen. …both Brad leaving Jen for Angelina after that movie, and the epic microbial growth in the diluted products. I had hoped I was wrong for the sake of all my friends who do this on the reg, but the agar doesn’t lie.
A few points to consider:
These massive colonies of bacteria/yeast/mold were after only 2 weeks of use. Most formulators will tell you the bugs can take hold within a day or two.
The bottles had no visible funk on them. The shampoo contents looked/smelled/felt normal. This is what’s so tricky about formulation. Your level of contamination can be devastating long before your senses can pick up anything as amiss. Unless you have your products formally tested (true challenge testing will put them through far more rigorous testing for stability than I did in my little informal, at home experimentation) you just don’t know what’s lurking in there. For personal use/gifts, I certainly don’t go through the effort/cost to pursue formal testing, but I do practice safe and appropriate formulation techniques, including the use of preservatives and emulsifiers when necessary. If I were intending to sell a line of products, I absolutely would have them tested.
Are these colonies of bacteria/yeast/mold dangerous? I have NO idea. They have good taste in wine, and have obviously watched too much Chopped given their critique of my cooking, but were pleasant little companions for our fireside snuggles. I used these contaminated products for 2 weeks, and I’m still standing, but I do have a few breakouts on my neck and shoulders where I’ve never had blemishes thus far. Coincidence? Possibly, but curious timing. The fact of the human experience is that we are living around and covered by microbes at all times. It’s a fantasy to think we are ever truly free of them. But using a product that is known to be contaminated because it was manipulated and used in a manner inconsistent with the intended usage - that doesn’t jive with me. It doesn’t jive with me on principle alone, but particularly if the microbes washed into my eye during shampoo rinsing, or if I had psoriasis/eczema/yeast overgrowth, or if I had an open wound, or if I were immunocompromised in some fashion.
Will I continue to use the products now that I see what’s growing in them? Hell no! The diluted versions have been dumped. Sorry my germy buddies, but not in my house. That’s my choice. If ultimately you are comfortable rubbing a product into your or your loved ones’ skin, and potentially getting it in the eyes, knowing it’s teeming with microbes? That is absolutely your choice.
Where did the germs come from? Isn’t distilled water sterile? This is how it goes with at-home formulation of hydrous products. All my supplies were as clean as possible, the water was new, storage was optimal, but here we are. Microbes are EVERYWHERE. In the air, on our surfaces (even if we’ve just cleaned), on us. Just the act of pouring the water from the jug into the Pyrex created plenty of potential exposure. Pouring the shampoo from the original bottle into the smaller ones did the same. The reality is unless you are formulating in some sort of vacuum-sealed clean room or isolation tank a la a scene from Outbreak, there are ample opportunities for contamination. This isn’t an issue when you are using appropriate preservation systems that can handle the inevitable contamination, but as noted, by diluting these products we have severely handicapped the original formula’s ability to do its job and keep the product stable.
So, what to do? If you care about avoiding microbial growth, the obvious answer is not to dilute these products.
If you’re wanting to get more mileage out of your shampoo… use less! I know it seems like a trite answer, and I think part of the issue is we’re conditioned to want big, lathery suds in our hair to feel “clean” while most natural products don’t foam up that much. Use a tiny amount, but apply it to really wet hair, adding more water as needed (to your hair, not the shampoo bottle!)
Or if you really just dislike the feel of super-thick and viscous shampoo going on, mix it with a handful of water in your palm prior to dumping it on your head. Is that not the same as diluting yet way safer as it’s done on an as needed basis?
Ultimately everyone can proceed as they see fit for their own, personal use, but I hope we can stop encouraging new users to do this (or if you must, disclose that they will likely have a contaminated product in no time at all.) As noted above, suppose someone had a cut on their scalp and introduced all that bacteria, or someone is immunocompromised in some fashion? It’s a dangerous game to play and I refuse to do it, not just to myself but to others who come to me for guidance.
If people are exploring natural products it’s usually because they are trying to better themselves, live a cleaner life, and find improved health and vitality for themselves and their family. Contaminating a beautiful product and setting someone up for potential adverse effects is not the way towards promoting wellness, IMO.
In the past I have discouraged this practice but offered up the compromise of only diluting small amounts in travel-size bottles, as hopefully they would be used up before the inevitable hot zone settled in. I was flat-out wrong that small batches would mitigate this problem, as this disaster unfolded in only 2 weeks. So my new answer? Just don’t do it. Know better, do better.
Onward and upward, my natural friends!
And if anyone knows a local distributor who carries Miraval rosé, hook a girl up!