If you want to check out the safety of the conditioner you are using, you can look it up at the Skin Deep cosmetics safety database. You can also search for low-toxicity conditioners. When I tried to do that, I found stuff that looked really benign, but cost $20 a bottle, plus shipping, and I wouldn't be doing anything to avoid buying bottles and shipping water around the planet.
So I looked for conditioner or hair gel recipes on the web. There are some out there, but a lot of them use the same chemicals that I'd prefer to avoid. There was one that worked great -- boiling flax seeds in water to make an amazing gel --but the result goes bad in less than a week and ends up smelling like rotten eggs. It's worth considering doing that and keeping it in the fridge to prevent spoilage, but I wanted to see if I could make something more convenient.
It turns out that this formula also has something of the same problem--it spoils eventually if it's not refrigerated--so unless you want to add preservatives, you need to make small batches, or keep most of it in the fridge. But it works well--as you see in the comments, some people swear by this formula.
Several comments also suggested aloe vera juice. You can buy that in a bottle or grow your own. That's also likely to have the problem of needing preservatives to last without refrigeration, but it seems to do a little better in my limited experimentation as far as keeping at room temperature.
Step 1: Obtain the ingredients
2/3 cup water.
xanthan gum and guar gum: 1/4 tsp each for gel; 1/8 tsp each for conditioner
1 tsp canola oil
I got the xanthan gum and guar gum from the bulk section of my local coop grocery store. They get it from frontier ; you can use their store locator to find a local source. You can also order direct from Frontier (both gums are in the cooking and baking ingredients section ), but you'll need to buy a 1-lb bag which is probably a lifetime supply for your entire neighborhood. You can order smaller quantities from Organic Creations , one of the few sources of soapmaking supplies that has mostly nontoxic stuff. Update: here's a source of really cheap guar gum but you need so little of it that a local bulk bin is the best option if that's available to you.
You don't really need both--they serve the same function (thickening, emulsifiying, lubricating), but they are supposed to work best in combination. If you want a vegan option, you might want to go with guar gum only. Xanthan gum is sometimes (particularly in the US) made from whey. I personally feel OK about utilizing whey which would otherwise likely go to waste, but if you want to be sure to have nothing animal based, you can simply go with guar gum, which is plant-based.
I don't have any scents in this--I prefer it that way--but you can add whatever scent you like. Experimenting with different scents can be fun. Soapmaking supply places have lots of wonderful scents available.
This is a pretty small quantity. One reason for that is that it doesn't have any preservative in it, and it's all food ingredients, so it will probably go bad in time. I haven't had trouble with that, but I haven't left any sitting around for more than 2-3 weeks. You could make larger batches, and keep most in the fridge. But you may want to start with small batches anyway so you can tweak the recipe for your hair.
You can read more at the end about how I picked these ingredients, other options to consider, and how to adjust the recipe according to what you want it to do.
Step 2: Mix the gum and water
First measure 2/3 cup water into your mixing container.
It works best to add the xanthan gum and guar gum to the water very slowly, so you don't get as many clumps. So first measure the amount needed (1/4 tsp of each for gel; 1/8 tsp each for conditioner), and temporarily put them somewhere, like in a spoon or a saucer. Sprinkle a small pinch on the surface of the water, and mix it in by capping and shaking the bottle vigorously. Repeat this process (dust the surface with a pinch, then cap and shake) until all the gum is mixed in. If you get some clumps that don't mix in, don't sweat it too much--if you don't get them mixed in today, they'll be easier to mix in after they soak overnight.
The mixture becomes amazingly thick considering how little is in it other than water.
Step 3: Add the oil
Step 4: Use it!
Depending on how much you make and how fast you use it, you might want to keep most of it in the fridge, and just a little bit in the bathroom--since all the ingredients are food, it will spoil. Depending on the temperature and other factors, it can last from a few days to a week. It will smell bad when it spoils. Filling lots of little bottles when you make it can be more convenient than refilling a little bottle every few days.
If you want to reduce the environmental impact of your shower in other ways, check out my Cozy Low-Energy Shower Instructable .
Step 5: Adjust the formula to your liking
To make it thicker and more of a gel with more holding power, use more gum.
Adjust the oil content--less if you find the original formula too oily; more if you have dry hair. If you add a lot more oil, it won't mix in and will just float to the top.
That's the end of the instructions--but you can also read on to learn more about other possible ingredients, how I chose these, etc.
Step 6: Why these ingredients
You could just use oil as a conditioner. You can buy oil sold for that, and you can find recommendations to use olive or other food oil as a conditioner. But it's hard to avoid ending up with very heavily greased hair, unless you oil it first and then wash the oil out.
With a small amount of oil diluted in a larger amount of water, it becomes easier to distribute a small amount of oil through your hair. But you need a way to get the oil and water to mix. The xanthan gum and guar gum make that possible, but they have other functions as well:
The xanthan gum and guar gum:
1) Make it possible to mix the oil and water. I don't know how much of that is just a result of their thickening effect slowing the rise of oil to the top, and how much is a true emulsification effect, but in any case it seems to work.
2) Their thickening effect is also useful in creating a thick gel that can help get your hair to go where you want it to.
3) A thicker liquid is easier to apply--it will stick to a comb, and less of it runs between your fingers and down the drain when you try to use it in the shower.
4) In addition to making liquids thick, they also make them super slippery, to make combing easier.
You can read more about xanthan gum and about guar gum in Wikipedia .
I tried both olive oil and canola oil. The canola oil seemed to give a lighter feel, which I preferred, but the olive oil smells good and might tame your hair a little more if that's what you want. I think canola oil will last longer before it goes rancid. Jojoba oil is a vegetable oil that is mainly used in cosmetics. It might be a better choice, both because it works well and because it doesn't go bad. But I thought it was more convenient to use something I have on hand anyway and can get in the grocery store.
Step 7: Other ingredients to consider
The usual vegetarian gelatin substitutes are agar and arrowroot . I expect that agar would would well to make a gel with stronger holding power. From what I've read, arrowroot gels aren't stable for as long, so my guess is that agar is better for that purpose.
You can get other ideas for good conditioner ingredients either by going to online stores that sell ingredients for making soap, lotion, etc., or by going to to the Skin Deep cosmetics database and sorting the list of conditioners by safety.
Most contain some kind of emulsifying wax--a wax that can be mixed with water, serving much the same function as the oil in our recipe, but easier to mix with water, and leaving behind a solid wax coating instead of an oily coating, so that the hair doesn't feel as oily. That's great, but if you go shop for an emulsifying wax, and look up its ingredients in the Skin Deep cosmetics database , you'll quickly find weird chemicals with serious safety concerns listed. The ones I found that don't have serious concerns are the emulsifying wax from Lotioncrafter comprising Behentrimonium Methosulfate and Cetearyl Alcohol, and the the "vegetable based" emulsifying wax from Organic Creations , which doesn't list ingredients, but the friendly folks there told me it comprises Cetearyl alcohol and polysorbate 60. If you look those up in the Skin Deep cosmetics database , you find them listed as low concern, but mostly because there is almost no information available about them. I suspect that stuff would work to make a better conditioner, but I prefer using my recipe that I'm more confident is benign.
Be careful of other emulsifying waxes. For example, this vegetable based emulsifying wax elsewhere contains PEG-150 which is rated as a "moderate hazard" with a 78% information gap on the Skin Deep cosmetics database .
Another common ingredient that sounds safe and helpful is "DL-Panthenol", also known as vitamin B5. It's "plant-derived" and acts as a humectant, attracting moisture and helping keep your hair and scalp from drying out.
You can also, of course, add whatever scent you like.