Shampoo and My Allergies

I've come to the conclusion I can't find a single commercial shampoo or conditioner that doesn't have at least one ingredient I'm allergic to. Most have mold-derived citric acid, and even if they don't, they have green tea, chamomile, sunflower seed, lavender, and similar ingredients known to trigger my allergies. Right now I use Suave because it causes only a mild reaction that is controlled with a Benedryl capsule--so far--but unless I discover some very unusual product, I'll probably have to resort to a homemade concoction. 

The problem with citric acid is that when it's used as an ingredient, it's almost always made from mold, not citrus. That means it causes a cross-reaction for people (such as me) who are allergic to yeast or mold. Not only would I have to find a brand that used a source from citrus, I'd also have to avoid several other ingredients.

Such brands as Suave and Herbal Essences advertise themselves as "natural" but that's just marketing. They're made with dozens of chemical ingredients including citric acid. Even Castille soap may contain citric acid, so don't use it unless you've read the ingredients label and know the source of the ingredients.

For True Botanicals a customer service representative tells me "Our Citric Acid is derived from 100% pure anhydrous citric acid from sugar cane. The crystallization process occurs by a submerged fermentation process, using natural carbohydrates from sugar cane." That's marvelous, but except both the shampoo and the conditioner use green tea so I'm sad to say that product remains a "no."

Bamford Botanic Shampoo contains lavender (another allergen for me) and citric acid of unknown origin.

If I can't find a commercial shampoo that contains nothing I'm allergic to, that means I must get used to using homemade shampoo and conditioner instead. That means getting the ingredients, utensils, and containers (got to have something to put the shampoo in) in preparation for the project, and make mixing up a batch a regular activity. Some sites that provide instructions on how to make homemade shampoo and conditioner follow.

Wikihow shows how to make homemade shampoo using soap flakes (leftover soap). It also calls for almond oil (nut oil) but I'm sure another oil can be substituted:  https://www.wikihow.com/Make-Shampoo

Shampoo in bar form can also be made from a soap base, if you want to use a soap mold, but the soap base called for in this recipe contains soybean oil. If I were going to try this process, I'd have to use a different base:  https://www.imperfectlyhappy.com/diy-melt-and-pour-shampoo-bars/

Here's a recipe for homemade hair conditioner that is very flexible, basically says any vegetable oil and any essential oil (for fragrance) mixed with guar gum and distilled water will do. Guar gum can be purchased online or at a health-food store:  https://www.myfrugalhome.com/homemade-hair-conditioner-recipe/

Here's another site that shows several recipes for homemade conditioner that appear to be free of anything I'm allergic to. I can use whatever essential oils I can tolerate, or just do without the essential oils. https://www.fabhow.com/diy-homemade-hair-conditioner.html