Keizo,
about chemical peelings books have been written, therefore we should have at least a dedicated tread just to those...
But to make a long story short lets say there are a few points that are worth keeping in mind:
- the main differences between chemicals is the dept of action, other differences like a tendency to work better in inhibiting dark spots (kojic acid) are present but relatively tiny, likely not worth too much concerns.
- dept of action is due by the kind of chemical, its concentration, how it is applied, combinations, layers and to some extents skin type
- skin type (Fitzpatrick scale) and subjective reaction is worth consideration
- reaction to chemical peelings needs training in order to prevent undesirable side effects
My suggestion for general purposes is to consider glycolic acid and TCA, as said there are a number of other kinds of chemicals but really differences are negligible and those two have been proven to be easy, cheap, effective and safe (salicylic acid tends to go systemic and prolonged use may cause some toxicity, even if probably unlikely why to risk when it doesn't provide any appreciable advantage against the safer glycolic?).
The darker the skin type the more concerns about chemical peelings because chances of unpleasant side effects are magnified.
Blacks, for example, should take great care especially with deeper peelings.
Glycolic acid is easy and basically there two ways of using it: everyday or once a week for a few weeks followed by a pause.
Everyday use should be with no more than 10% strength, needs no buffering, is generally very well tolerated with almost no irritation if any, very mild peeling might occur after few days of use but usually nothing major, can be done all year long, sun and light exposure aren't of concern, works very well for PIMPLES, BLACK HEADS and improved skin tone, improve absorption of other supplements therefore works well with HA or whatever one wishes.
It doesn't erase wrinkles or dark spots, maybe ameliorating some very fine and subtle ones but isn't that its intended action, it is a great way to train skin for future more aggressive peelings.
Once a week needs something between 20 and 35% strength (stronger is not going to be more effective, it will just lead to more irritation), it needs buffering by applying a solution of water and baking soda after 6-10 minutes in order to neutralize the acid, mild peeling may be experienced but usually nothing major, very tiny wrinkles and dark spots may be erased but nothing dramatic, sun exposure is better to be avoided during periods of treatments.
In my experience glycolic acid is better used everyday at low strength instead of once a week at higher strength but both ways do provide skin training for future deeper peelings.
Applying can be done with a brush or with a cotton pad (or gauze), brush is more gentle, cotton pad or gauze allows for rubbing which leads to deeper penetration but don't be tempted to achieve a deep peeling with glycolic acid by mean of using higher strength or heavy rubbing, it just doesn't work and great irritation is all you'll get.
It is smart practice to start low and slowly moving up, low on strength, low on time before buffering (when buffering is needed), low on rubbing (in my opinion the soft brush is better, rubbing is not going to turn glycolic in TCA anyway).
TCA needs a cautious approach, this is where serious damage can be done but it is where dramatic results can be achieved too.
TCA is real peeling, no room for doubts here, strength range from 25 to 50% with probably best at 35%, doesn't need buffering, not to be used more than twice a year and since sun exposure is of concern for a while after a treatment once a year in winter time is likely all you want.
DON'T jump on it without previously training the skin with milder peels like glycolic for at least few months!
Side effects on untrained skin range from discoloration (dark areas) to severe burning scars, eyelid dropping or horrible irritation.
TCA is not forgiving, a mistake here and you'll regret it, really.
More about TCA on request or, even better, in a dedicated tread.
Yes, taurine and psoriasis don't go well along, even at low dosage or only topical since goes systemic anyway.
Whom suffer psoriasis or is psoriasis prone should avoid at all costs taurine in any form, you aren't missing anything special anyway.
It might lead to dandruff.
MSM is a source of sulfur, if someone is sulfur deficient supplementing MSM might be effective, if one has a decent nutritional habit which includes eggs and cruciferous veggies, for example, sulfur deficiency is unlikely of concern and supplementing MSM unlikely to be a life changing experience.
MSM is cheap and in reasonable amounts likely quite safe, at worst isn't going to add much....
It kind of enhance absorption of other compounds taken along with it, therefore it might act as an absorption enhancer of supplements both orally and topically, adding some to gels or masks may be worth, as usual don't expect miracles from it but for about 10$/kg at least isn't likely to drive you broke.
astaxanthin, lycopene, lutein, pycnogenol
Antioxidants, some of them outrageously expensive,,,ALA is likely better and cheaper (topically is one of the very few things making a real difference).
Proper needling isn't as straightforward as one may think, not rocket science but still needs to be done properly other ways results will be unsatisfying, most people don't have a clue about how to do it...and most online videos and forums are the prove of it.
I want tight, glowy, plump skin
Skin texture can be improved with chemical peels, topical moisturizers like HA gels, topical antioxidants like ALA, proper needling (which provides a very close effect to that of glycolic acid at least in this regard).
Everyday glycolic 10% in HA gel provides better results than retin A, is much cheaper, much better tolerated and side effects free, plus it doesn't go systemic and DOESN'T LEAD TO SUBCUTANEOUS FAT LOSS.
Tight and plump are very related to subcutaneous fat and facial bones, not exclusively but much so.
And here we are again...
You ladies out there likely don't notice it (yet) because women carry more fat than men do (a woman 24% fat body mass equals to 15% male, talking about how "normal" it looks), distribution of fat is different too, women carry most of it on hips and boobs, of course, but on face too, while men tend to carry it mostly on the belly, since fat distribution is hormonally dictated there might be exceptions, of course, but as a rule of thumb that's how it is.
You ladies have fatter faces which is MORE SUBCUTANEOUS FAT than men do, therefore the retin A caused subcutaneous fat loss is much less evident for most women than it is for men, at least for a while....
You spread you beloved retin A on you lovely face, those first tiny wrinkles that freaks you out kind of magically disappear and you do feel as happy as first date day....well... see you when you'll be 50 or more: when subcutaneous fat starts to drop below a certain level you'll regret big time all that retin A spreading.
And about wrinkles....
Has anybody ever seen a fat person with a wrinkled face?
Well show me a picture than!
Because fat tighten and plump that skin on top of it!
Got wrinkles?
Try pulling in the right direction your skin near by...oooh, you see, gone!
The plastic surgeon practice of lifting tells you anything?
Now, a few tiny wrinkles here and there are easy fixable with some retin A, better with other means as above described but anyway...
...but when skin starts developing wrinkles due to sagging there is no amount of retin A, needling, peeling, HA, gels or creams that will make a dent, only crosslinked HA injections (fillers), autogenous fat transplant or other skillful plastic surgeon interventions will be able to fix it somehow.
Therefore take good care of you facial subcutaneous fat or you'll regret...and retin A isn't a smart choice in that regard.
For an overweight or fat faced person all this may be irrelevant or a face fat reduction even desirable but that is unlikely to be most people reality.