Vitamin A Pommade

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.

retinyl palmitate --> retinol -- > retinaldehyde --> all-trans-retinoic acid

As we wrote in our lengthy retinol description the problem is that the conversion is not terribly effective. The evidence that RP is still an effective anti-aging ingredient is not very strong, in fact, it's weak. Dr. Leslie Baumann in her fantastic Cosmetic Dermatology book writes that RP is topically ineffective. 

What's more, the anti-aging effectiveness is not the only questionable thing about RP. It also exibits questionable behaviour in the presence of UV light and was the center of a debate between the non-profit group, EWG (whose intentions are no doubt good, but its credibility is often questioned by scientists) and a group of scientists and dermatologists lead by Steven Q. Wang, MD,  director of dermatologic surgery at Memorial-Sloan Kettering Cancer Centre. 

Dr. Leslie Baumann wrote a great review of the debate and summarized the research available about retinyl palmitate here.  It seems that there is a study showing RP being photo protective against UVB rays but there is also a study showing RP causing DNA damage and cytotoxicity in association with UVA. 

We think that the truth lies somewhere in the middle, and we agree with Dr. Baumann's conclusion: "sufficient evidence to establish a causal link between RP and skin cancer has not been produced. Nor, I’m afraid, are there any good reasons to recommend the use of RP". We would add especially during the day!

Bottom line: If you wanna get serious about retinoids, RP is not your ingredient (retinol or tretinoin is!). However, if you use a product that you like and it also contains RP, there is no reason to throw it away. If possible use it at night, just to be on the safe side.