Is vitalism actually discredited though? Sure, urea & synthetic urea are chemically the same and behave identically in a chemical sense — but wouldn't a vitalist argue that there's more than just chemistry at play?

The problem with vitalism is that it's unfalsifiable; that doesn't mean that it's wrong, simply that science doesn't have the ability to refute it.

This reminds me of a student's comment: "oh but that's only true within the confines of logic". That is, i'm sure a 'vitalist' would argue: "oh that's just chemistry, what of beyond chemistry?" to which i'd be forced to ask: are we talking about concepts where science isn't accepted? isn't that the realm of spiritualism? ("this protein is imbued with an ineffable living essence; whereas the one you synthesized must necessarily lack it") There are certainly folks who believe that things go on in a living system's metabolism which transcend chemistry, but on that point we part ways and i wish you well. and/or for me vitalism was forever falsified when a synthetic molecule and a 'natural' molecule co-crystallized.

I've always taken the "natural is better" argument to be based on what else is in the product. The drug industry has a long history of taking a complex natural product and isolating out specific chemicals, then patenting a manufacturing process for those chemicals to sell them as drugs. Sometimes that's fine, but there are many cases where the drugs have side-effects that the natural product doesn't have and that's due to the other stuff in the natural product.

So your analogy really should be between lab-synthesized vitamin C and a piece of citrus fruit. The fruit is going to be better for your overall health because it's got more in it than just L-ascorbic acid. For example, it's got fiber, which is likely to slow down the passage of the vitamin through your digestive system, which will help you absorb more of it for an equal dose.

no... my analogy would be fundamentally a different analogy if i compared a bottle of vitamin C to a whole piece of fruit (quite "apples and oranges" in fact). I wanted to underscore that two pure substances, one synthetic and one extracted from nature are indistinguishable. When i teach biochemistry i'm always struck by the resistance to the pivotal biochemical scientific experiment of Friedrich Wöhler who synthesized urea and showed that it's identical in every sense to the urea extracted from urine. Thereby ending the notion that there is a vital principle. One may always quibble about contamination, but carbon atoms linked to other carbon atoms are the same whether made in a cell or made in the laboratory.

I agree with you that the two chemicals are indistinguishable; I just think that that's not really the issue when people prefer 'natural' products. Now, most people also don't get the distinction you're making, because they're not chemists. What they see, and what they're reacting to, goes more like this:

Joe Public> I have a headache.

Folk Medicine Dr> Here, drink some willowbark tea.

DrugCo Chemist> No, take this aspirin. It's chemically identical to the active substance in willowbark tea, but much more convenient!

Joe Public> My headache is better, but now my stomach hurts. That never happened with the tea.

DrugCo Chemist> Oh, you have an ulcer. You're a sick person. Take this antacid medicine!

Joe Public> My stomach feels better, but now I'm constipated.

DrugCo Chemist> Wow, you're really sick... here, take this laxative!

Folk Medicine Dr> All these unnatural drugs are killing you. You should really just take the tea.

Joe Public> Yeah, I think you're right. Natural is better.

yes, and the relative merits of well defined substances versus macerated hot water plant extracts will be discussed to the end of time. just don't ascribe magical 'vital' properties to either one. by the bye, drink enough willowbark "tea" and you might succumb to salicin poisoning. it's said to have shortened Beethoven's life. (next up: homeopathy doesn't cause any side effects)

You seem to think I'm arguing with you. I'm not. I'm trying to explain why people claim that "natural is better", even if they understand that the active components are the same.

Also, you're the one talking about magical vital properties, not me. It's a well-established fact that substances in combination can have a different overall effect than they do in isolation. There's nothing magical about it.

Homeopathy is an absolute scam. And yes, there are scammers who take advantage of the 'natural is better' idea to sell useless products.