Should DayQuil Be Legal?

If anything, you need honesty from healthcare companies in the first place if you're even going to begin making an informed decision. You're putting the cart before the horse here: people absolutely should be doing their own research before medicating themselves, but it is the OTC companies that obstruct that.

And, secondary to all of this, your analogy about shampoo is misinformed. Still, it is fitting for this scenario, but not in the way you intended. There are lots of different hair types, including ethnic hairstyles that require specific treatments. There are also a number of lifestyle choices that can change your hair treatment needs. As a result, the shampoo aisle actually is stocked with a wildly varying assortment of haircare choices, but actually figuring out what product works best for your needs can be challenging because it is walled behind layers of marketing nonsense that don't inform the consumer adequately on what makes each product different. This isn't much different than the problems in the medicine aisle.

It took a lot of secondhand research to find the ideal hair care product for my thick, curly hair that would mitigate the damage of thrice-weekly swimming in a chlorinated pool. I can assure you, not everything in the shampoo aisle is exactly the same. It was especially hard figuring this out as a man, when so many products are arbitrarily marketed to specific genders.

"Using objective and subject assessment tools validated in pediatric populations, this study provided evidence of the antitussive efficacy of DXM in children, aged 6–11 years, at the current OTC monograph dose and labeled indication. Compared with placebo, DXM treatment reduced cough rates 21.0% over 24 h (primary endpoint) and 25.5% during daytime/awake hours. In addition, children treated with DXM reported greater reductions in cough severity and frequency in the mornings and afternoons over 3 days than children treated with placebo. These treatment effects were statistically significant despite the study not reaching its planned sample size and are medically relevant."

Also as I mentioned in another comment, the author of original article misrepresents the findings of their own citation. DXM was found to be effective in adults, just not children.

Then, there _are_ arguments about whether generics face adequate testing to ensure the same quality as the originally-approved name brand drug. A lot of this is FUD - I'll happily buy generic acetaminophen in the US - but it's not a totally irrational concern. I doubt any regulator ensures generic equivalence to the same degree of conformity that a big pharma companies' own quality control does.

For example, I personally find real differences in the jankiness of different asthma inhalers, even amongst generics. Maybe that's because I don't shake/use/clean them exactly per the directions, but then that's real-world use for you. My personal experience says brand-name Ventolin has solved a "robustness against user error" problem in a way some alternatives often have not, suggesting the FDA does not enforce equivalence on this dimension. It's not enough of a difference for me to go name-brand, since out-of-pocket price differences can be egregious, but I do distinguish between otherwise-unknown generics.

Finally, you may trust the UK regulator and so do I, but traveling somewhere without good regulatory oversight, I'd probably reach for Panadol - assuming it seemed authentic - over a generic brand I'd never heard of. Brands have value and brand owners have a lot to lose, which is a kind of insurance (see 1982 Tylenol recall).

But thanks for the input, sweetlips!