Olay Regenerist

Anti-aging Wrinkle Correcting Treatment Serum

As Dr. Fulton (the scientist behind both Retin-A and RP) puts it in his patent paper,  "Other esters of vitamin A obtained from, for example, palmitic acid and acetic acid do not have the therapeutic advantages found with vitamin A propionate ..... Presumably, the [Retinyl Palmitate] molecule is so large, it is not able to transdermally reach the necessary part of the skin for activity. Similarly, vitamin A acetate is too small molecularly and therefore easily recrystallizes from any solution.....vitamin A propionate is the appropriate molecular weight and configuration to both remain in a stable solution and to be transdermally delivered to a site where it is active." So while the effectiveness of other retinol esters is highly questionable, Retinyl Propionate seems to be the most effective retinol ester molecule, and it "unexpectedly provides all the benefits of vitamin A acid but minimizes the negative side effects", at least according to Dr. Fulton, the inventor of the molecule. 

We know what you are thinking! This sounds great and all, but what about some proof? Some backup data not from the inventor himself?  We looked into it and found three studies working with Retinyl Propionate.

In a 2007 study by Dr. Draelos, she references a 12-week, double-blind, placebo-controlled clinical trial that compared the effectiveness of 0.15% retinol with 0.3% Retinyl Propionate. Both actives were effective in reducing the appearance of facial wrinkles and hyperpigmentation and the 0.3% RP worked a bit better. 

Another research that was done by Procter & Gamble combined multiple anti-aging actives including niacinamide, peptides and 0.3% of Retinyl Propionate and they compared this regimen with a 0.02% tretinoin regimen. They found that the cosmetic regimen was tolerated better, worked faster and gave comparable results. All this sounds very promising for RP, however, it is hard to know how much the other actives contributed to the positive results. 

Last, but not least there is a study from 1998 that tested a 0.15% Retinyl Propionate cream and after 24 weeks found no statistically significant difference between the effects of the retinyl propionate cream and the placebo preparation for any of the clinical parameters of skin photoaging. However, after 48 weeks, the 0.15% RP worked wonders for actinic keratoses, a rough, scaly patch caused by UV damage (its name contains actinic, but it is not acne, has nothing to do with it (!)).

So, it seems that the minimum effective dose of Retinyl Propionate is larger than 0.15% which is not surprising given that it has to do three conversion steps to reach the active form, retinoic acid. But 0.3% RP (or more, obvs) seems to be an effective dose, and even though the proof is not as solid as it is for retinol itself, if you are looking for a more gentle alternative, or if you are in the mood for experimentation, Retinyl Propionate looks like a noteworthy alternative and the most promising option among retinol esters.

The manufacturer did several studies to prove that Argireline really works and it does (just not as well as Botox). In-vivo (made on real people) tests showed that using 10% Argireline solution around the eyes for 15 days decreased wrinkles depth by 17%, while a 5% Argireline formula applied for 28 days did almost the same with a decrease in wrinkle depth by 16.26%. A Spanish University also did some research and found that Argireline increased the level of skin moisturization and decreased both the depth and width of wrinkles "significantly". 

This means, Acetyl Hexapeptide-8 does have some ability to smooth wrinkles (but not as well as Botox - sorry, if we sound like a broken record). Also, we have to agree with TruthInAging, that it's not a collagen builder and not a preventer of structural aging (think vitamin C, AHAs or retinol); it's just a quick fix. If you are looking for one, this could be your thing. If you are more of a "let's treat this aging thing properly" type, then it's probably not your thing.

Though most research is manufacturer sponsored, the clinical studies about Palmitoyl Pentapeptide-4 are promising.  In short, it can reduce fine lines, wrinkles and improve skin texture significantly (and at crazy low concentrations, the studies were done with just 3 ppm that is 0.0003%).

There are also studies comparing Palmitoyl Pentapeptide-4 with anti-aging gold standard, retinol. One of them compared 3ppm Pal-KTTKS with 700 ppm (0.07%) retinol and found that they showed similar wrinkle improving ability with the peptide showing better skin tolerability.

Bottom line, if you are into peptides, this is a good one to try.

Other than that we can write about manufacturer-done in-vitro (in the lab, not on real people) studies that show Carnosine to have anti-glycation properties. Glycation is the not-so-nice process that happens when we bombard our body with too much sugar that results in damaged body proteins and eventually in more wrinkles.  

Also, a manufacturer done in vitro study shows that carnosine might have collagen-boosing magic power. However, the 2017 research paper also mentions that even though Carnosine is a small molecule, it is water soluble and does not penetrate the skin past the top layers so we have some doubt if the collagen-boosting works in real life. We could find one anti-aging study made on real people that mentions Carnosine, but it was combined with a bunch of other anti-aging actives so it is pretty much impossible to know what Carnosine did or did not. 

One last thing to mention is that there is also a manufacturer done clinical study (done on real people) that shows carnosine being effective against the damages caused by infrared (IR) radiation. (source)

It’s an ingredient whose safety hasn’t been questioned so far by anyone (at least not that we know about). BG is approved by Ecocert and is also used enthusiastically in natural products. BTW, it’s also a food additive. 

In spite of this, if you search for "hyaluronic acid vs sodium hyaluronate" you will find on multiple places that sodium hyaluronate is smaller and can penetrate the skin better. Chemically, this is definitely not true, as the two forms are almost the same, both are polymers and the subunits can be repeated in both forms as much as you like. (We also checked Prospector for sodium hyaluronate versions actually used in cosmetic products and found that the most common molecular weight was 1.5-1.8 million Da that absolutely counts as high molecular weight).

What seems to be a true difference, though, is that the salt form is more stable, easier to formulate and cheaper so it pops up more often on the ingredient lists. 

If you wanna become a real HA-and-the-skin expert you can read way more about the topic at hyaluronic acid (including penetration-questions, differences between high and low molecular weight versions and a bunch of references to scientific literature).

There is also some research showing that citric acid with regular use (think three months and 20% concentration) can help sun-damaged skin, increase skin thickness and some nice hydrating things called glycosaminoglycans in the skin. 

But according to a comparative study done in 1995, citric acid has less skin improving magic properties than glycolic or lactic acid. Probably that’s why citric acid is usually not used as an exfoliant but more as a helper ingredient in small amounts to adjust the pH of a formulation. 

Other than having a good safety profile and being quite gentle to the skin it has some other advantages too. It can be used in many types of formulations as it has great thermal stability (can be heated up to 85°C) and works on a wide range of pH levels (ph 3-10). 

It’s often used together with ethylhexylglycerin as it nicely improves the preservative activity of phenoxyethanol.

Anyway, it doesn't matter if it reflects or absorbs, Titanium Dioxide is a pretty awesome sunscreen agent for two main reasons: it gives a nice broad spectrum coverage and it's highly stable. Its protection is very good between 290 - 350 nm (UVB and UVA II range), and less good at 350-400 nm (UVA I) range. Regular sized Titanium Dioxide also has a great safety profile, it's non-irritating and is pretty much free from any health concerns (like estrogenic effect worries with some chemical filters).

The disadvantage of Titanium Dioxide is that it's not cosmetically elegant, meaning it's a white, "unspreadable" mess. Sunscreens containing Titanium Dioxide are often hard to spread on the skin and they leave a disturbing whitish tint. The cosmetic industry is, of course, really trying to solve this problem and the best solution so far is using nanoparticles. The itsy-bitsy Nano-sized particles improve both spreadability and reduce the whitish tint a lot, but unfortunately, it also introduces new health concerns. 

The main concern with nanoparticles is that they are so tiny that they are absorbed into the skin more than we want them (ideally sunscreen should remain on the surface of the skin). Once absorbed they might form unwanted complexes with proteins and they might promote the formation of evil free radicals. But do not panic, these are concerns under investigation. A 2009 review article about the safety of nanoparticles summarizes this, "to date, in-vivo and in-vitro studies have not demonstrated percutaneous penetration of nanosized particles in titanium dioxide and zinc oxide sunscreens". The English translation is, so far it looks like sunscreens with nanoparticles do stay on the surface of the skin where they should be.  

All in all, Titanium Dioxide is a famous sunscreen agent and for good reason, it gives broad spectrum UV protection (best at UVB and UVA II), it's highly stable, and it has a good safety profile. It's definitely one of the best UV-filter agents we have today, especially in the US where new-generation Tinosorb filters are not (yet) approved.