In short, the efficacy of most cosmetics is illusory and marketing-inspired and that's the end of it, but I will still make a minimal scientific argument🧐
I'll do it by popular categories of cosmetics.
Products with hyaluronic acid. In any cosmetics store you will see creams, serums, fluids, tonics on which it is drawn and written how you will be rejuvenated after their use😄 Unfortunately, it's all lies. The argument here is very simple - this acid is needed inside the tissues, not on the skin...
And its synthesis depends on different nutrients and your metabolism. Who needs details - see links at the end of the post, there is an article in Russian by a biochemist.
Sunscreens. They are necessary, but not all the time and not everywhere. For example, in the climatic conditions of my Kiev, it is more like marketing. But somewhere closer to the equator it is a necessary thing. For example, when I was in Indonesia I was surprised by local savages that walked in jackets on the street at +35. Later when I got sunburned it became clear to me why 😄 But standard SPF 50+ cream is not enough, for example surfers used a special clay-like paste with zinc oxide that did not wash off the whole day. You should also realize that extremes are bad - without sun we don't get vitamin d and we don't train the antioxidant system. But also when you get a lot of it you get mutations in your skin cells. Remember that and don't go to a tanning salon😉
Cosmetics for problem skin. These products usually contain acids: salicylic acid, azelaic acid and others. A person smears with them and poison both the bacteria on the skin and the skin itself 😕 Flaking occurs, which is the dead cells of the basal layer of the skin. And behind it, new cells appear. And this is the process being passed off as a benefit and effect. In fact, it is a targeted damage to the already problematic skin in anticipation of regeneration. Pimples from this can pass, for the time of use, but you can not cure them so. And they'll tell you that it's a chronic condition and you need to ointment all the time 😁
Shampoos, washes. The direct purpose of these products is to wash away dirt. Cheap products do it aggressively, expensive ones delicately. But you should not think that your skin or hair will be better after them. For example, shampoo manufacturers add special silicones for shine and smoothness of hair. They add substances that mask pores. But all these tricks have a very temporary effect.
Now a couple of words about cosmetics that do bring benefits. Mostly it is Asian manufacturers (Japan, South Korea). I will not advertise anything, but I will tell you what you can pay attention to:
✔️Cosmetics with glutathione
✔️Cosmetics with coenzyme Q10 (but not everywhere the working form of this substance, you need to try different manufacturers).
✔️Cosmetics with fucoidan (it seems that only Japan makes it)
✔️Peptide cosmetics can help with fine lines and improve skin tone (e.g. copper tripeptide).
✔️Cosmetics with plant extracts (like centella asiatica, pomegranate extract, etc., there are many) can reduce inflammation.
✔️If you have problem skin avoid creams and any oil base. Only gels, serums, toners.
✔️Cosmetics with probiotics can help with dermatitis and acne by changing the local immunity of the skin.
✔️Aminexyl shampoo can accelerate hair growth.
And lastly, remember that the condition of your skin, hair, nails - first of all depends on genes, secondly on your current metabolism, and only lastly on care🧐
For example, I think each of you have someone you know with perfect skin that never used sunscreen or some other creams. Think about it 😉
https://habr.com/ru/post/569954/
http://www.ncbi.nlm.nih.gov/pmc/articles/pmc8627341/
https://pubmed.ncbi.nlm.nih.gov/35083444
https://pubmed.ncbi.nlm.nih.gov/33526970
https://pubmed.ncbi.nlm.nih.gov/26648450
https://pubmed.ncbi.nlm.nih.gov/26848220
