I just wanted to post my thoughts on natural products. I completely agree with Jessiebanana that it is erroneous to conflate "natural" with "safe." On a chemical level, molecules are molecules anyway, and if an ingredient "sounds chemical-y" it doesn't mean it's bad for you or your hair fatty alcohols being a good example.
That being said, I do like to run my products and ingredients by Skin Deep, and I'll spend time on the site discovering new companies as well. Skin Deep® Cosmetics Database | Environmental Working Group
Interestingly, the small natural boutiques that have a health and eco-conscious approach often score the best. Generally these kinds of companies tend to avoid putting things like parabens and DMDM hydantoin in their products. I'm talking about the companies that are dedicated to their cause, not the greenwashing types.
Bigger companies can certainly make safe products, but often I run into situations like this one: I just bought the CeraVe cleanser and lotion which I've been using on my face, and i really like it, think it's helping with my acne, except it has parabens in it. The product scored well on the site, except for the parabens. This really annoys me, I don't really want to use something that is good for my skin but ultimately bad for my body.
If you're using something on your skin or hair that is actually edible like FSG (would probably taste bad) there's no way that it could worse for you than a store-bought gel (unless of course, you're allergic to flax or it's gone bad).
A well-formulated health-oriented store-bought gel shouldn't be a problem however. You have to dig a little bit, run some searches and make the best decision based on all the literature available at the time of purchase. In the long run, we may find that even more ingredients are possibly problematic, even the ones deemed safe at one point. This gives some people the attitude of "well I'll just use whatever anyway." I disagree with this. If an ingredient has links to cancer I don't see any reason why I would continue using it. If other ingredients are deemed not as safe in the future, then I'll stop using those as well.