I see advertisements on TV for products that "nourish your skin", products that "detox your body" and now I've seen "vitamins for healthy hair".
What rubbish this all is. Holland and Barrett, for example, sell "Viviscal hair growth programme tablets", at £200 for one treatment (takes six months). The claim they make is "helps maintain normal healthy hair growth from within". At the end of six months, you'll find that your hair has grown normally? ... wow! I get the same effect without doing anything. I even have to pay someone to cut some of it off.
Likewise "detox". My kidneys and liver do that for me. H&B offer 38 products in their "detox" category. But the whole "detox" industry is based on a lie.
The marketers have taken the concept of "vitamins" and harnessed it for their own benefit. A vitamin is a chemical that your body can't synthesise (or can't synthesise enough of) and so you have to eat some. But once you have enough of it, more of the vitamin does nothing for you.
More broadly, the marketers have hijacked everyone's understandable desire for good health, and they try to persuade you that their product is essential for your wellbeing.
If you don't get enough vitamin C, you get scurvy. It's actually quite difficult to not get enough vitamin C, you have to be at sea for months on end and not eat any citrus fruit. Vitamin deficiency diseases are, in populations rich enough to waste money on unnecessary pills, very rare.
I'm not going to give you health advice. Except that, unless your GP has told you to, don't waste your money on "health products".
And don't get me started on homeopathy, alternative and complementary medicine. That's what killed Steve Jobs.