In theory, it is possible. For example, two oils can make an oily serum. With the right fatty acids, it may help your skin a bit. But in real life? No. It doesn’t happen.
Now, if you add water, that makes two ingredients a non-viable choice. Or, rather, too viable for bacteria and mold. Water and hyaluronic acid will make a gel, leave it two days alone and the gel will become a liquid after the hyaluronic acid is devoured by bugs in the environment, they love hyaluronic acid.
Can sunscreen have just two ingredients? Maybe: zinc oxide dispersed in oil or water will make a paste that will reflect the sunlight and protect your skin. It will also feel gritty and unpleasant and will look like you painted your face.
How come some people think that their sunscreen has just two ingredients? The letters for “active ingredients” are larger on the label. It could be zinc oxide and titanium oxide or maybe zinc oxide and oxybenzone or a similar chemical. These “just two” ingredients will be in a carrier that will make the sunscreen active ingredients more easily applied, and it will feel better against the skin. The many ingredients in this base will be in smaller letters and if you are not careful your eyes will not even see them! The carrier may even help prevent the sunscreen from washing away the moment you get into the water.
What is an “active ingredient” in an OTC (over-the-counter) medical product like sunscreen? It is an ingredient that the FDA has classified as effective to prevent damage to the skin or to address a skin problem like acne. Toothpaste and deodorant are also considered OTC medicines and are regulated as such. Besides these active ingredients, there is a long list of ingredients (called inactive but only by the FDA definition) which include solvents, thickeners, pH adjusters, antimicrobial preservatives, fragrances, etc.
Learning to read an ingredient label is a skill that will become useful in the skincare or cosmetic counter and in the supermarket. My book has a whole chapter on this subject.
Here is the beginning of the chapter:
How to read at an ingredient list. First: don’t panic!
The ingredient lists on skincare products’ labels look, at first sight, practically undecipherable, and probably just the same at second sight. And yet, if you dive in, it is possible to understand what’s in that product. It helps if you know some chemistry, but if not, you can still work it out with patience, and if all else fails – you can write to me (see my website, hannahsivak.com).
A good start is to try and separate the ingredients into two lists: a list of components that make the carrier, be it a cream or serum, and a list of the actives dissolved in the cream or serum. For a simple cold cream, you will find just a few components: water, mineral oil (very emollient, a skin conditioner), wax (a thickener), and fragrance. For a commercial product, the lists get longer because formulators use a variety of ingredients to improve feel, texture, stability, and color.
For example, here is the list of ingredients for Skin Actives’ Canvas Cream, a base cream that works well in many jobs. This formulation doesn’t contain mineral oil, making it lighter and suitable for people with acne. We call it a base cream because we can modify it for any purpose (anti-acne, rejuvenating, etc.) by adding active ingredients. After each component, you will find between brackets its role in the product.
Note: Ingredients are presented here in lower case, and Latin names of the plants were removed to facilitate reading. INCI nomenclature capitalizes terms in the labels even when in scientific use, this is not needed. For plant names, the INCI follows the Linneaus binomial system, without italicizing genus and species.
water (formulation base)
jojoba seed oil (emollient)
sorbitol (water-binding and slip – ease of application)
butylene glycol (slip)
cetyl alcohol (moisturizer and thickener)
glyceryl stearate (moisturizer and thickener)
PEG-100 stearate (moisturizer and thickener)
stearyl alcohol (moisturizer and thickener)
sesame seed oil (moisturizer)
sweet almond oil (moisturizer)
avocado oil (moisturizer)
sodium hyaluronate (water binding, nutrient)
polysorbate 20 (emulsifier)
citric acid (to adjust pH)
dimethicone (skin conditioner, slip agent)
aminoethyl propanol (to adjust pH)
phenoxyethanol (antimicrobial preservative)
methylparaben (antimicrobial preservative)
propylparaben (antimicrobial preservative)
Claims on this page have not been evaluated by the FDA and are not intended to diagnose, cure, treat or prevent any disease.