Obagi Medical Professional-C 20% Serum Review

Here is my 3.5 month review for the Obagi Medical Professional-C Serum.

Disclaimer: @harbenhouse sent me this serum to get my feedback on but there was no requirement to post or share my thoughts


This is a Vitamin C serum that uses 20% L-Ascorbic acid (which is the pure form of vitamin C and has the most research to back up its effects). Most of the vitamin C serums I have used and love (like Paula’s Choice Vitamin C Booster) are 15%, so this was an increase in concentration from those.

I don’t love the packaging on the Obagi (which I will get to later) and I also wish that it had Ferulic acid along with Vitamin E (and some additional brightening, soothing, hydrating, or reparative ingredients would have been nice). Plus, I could do without the added fragrance.


$127 for 1 oz. (wait for coupons because you can often find 25% of deals at dermstore and other retailers).

Right now Obagi is 25% off at Dermstore with the code OBAGI25.


Every morning after cleansing I would apply ~10 drops directly on my skin, with 6 focused on my face (I do 2 drops on each cheek, 2 for my forehead and the remaining ~4 drops on my chest & hands).

I felt like it absorbed nicely and didn’t feel terribly tacky (although I always apply other products on top). It worked well under makeup and when I did a split face using Paula’s Choice Vitamin C serum on one side of my face and this on the other for 1 week I didn’t notice any differences in terms of how shiny my face was.

Color of serum on the day I opened it. It didn’t oxidize much from this in the 3-4 months I have had it open


I’ve included before and after photos for you to dissect and judge for yourself. In the full face photo I wasn’t blown away by an obvious improvement, but when I looked at specific areas like on my one side of my face and on my forehead I was happy to see some noticeable fading of hyperpigmentation. (see photos below).

Also, keep in mind that Vit C protects your skin in addition to correcting it. In other words, it can prevent your skin from showing signs of aging due to UV exposure or other environmental stressors. However, since I used this all over, there is no way for me to assess whether it prevented my skin from looking worse than if I hadn’t used it (That’s why I tend to focus on fading of hyperpigmentation because that is easier to gauge).

Obagi Medical Professional-C before and after 3 mths of use
Obagi Medical professional-C before and after 3 mths of use

However, I did notice that over time this dehydrated my skin. It took me awhile to identify what was going on, but after I stopped using the Obagi it became more clear that it was dehydrating my skin a bit. For example, while using it I found that I had to compensate with more hydrating layers than usual, otherwise some dehydration lines were more noticeable. I am wondering if the reason that I found this drying was the alcohol high up in the ingredient list paired with a lack of a lot of hydrating, soothing ingredients to offset that.

Another reason it may have been drying is that the pH of this is really low (pH=2.0).

Pros and Cons

For me, the biggest cons are price, faulty packaging and some signs of dehydrated skin. In terms of packaging… I was annoyed because I actually had to find a different pipette so that I could switch mine out otherwise it wouldn’t seal properly (see photo from my Instagram stories). L-Ascorbic Acid is highly unstable and needs to be stored in a cool, dark, air-tight package. So having the cap not screw up properly is problematic! After posting those stories to IG, I received a mix of messages with half saying they experienced the same thing and half saying they didn’t. So there appears to be some quality control issues.


The number one question I get is whether I like this more than Paula’s Choice. In terms of comparing its efficacy…I can’t do that because I didn’t do a split face comparison to really compare the two. I can anecdotally compare the results to the results I have experienced with PC in the past, but note that that is really imprecise. But I will share my thoughts and you can see what you think.

Obagi Professional-C 20% did a good job at breaking up some stubborn pigmentation and lightening pigmentation overall. I think I saw similar results as I have seen with Paula’s Choice in the past (I have some photos in my Vit C highlights on my Instagram page and on my blog that you can check out), but I think it did do a really good job at a somewhat quickly fading a stubborn cluster of pigmentation on my one cheekbone. PC has been fading the same cluster of pigmentation and it seems like the reduction over 2-3 mths was similar for both (but I included a photo for y’all to examine).

All things being considered I think their results are comparable. But all things considered, I prefer Paula’s Choice (and Maelove Glow Maker).

First, I prefer the price ($73 per oz vs $127 per oz) and packaging of PC (although I will say that Obagi oxidized less than PC usually does in 3 months). then that makes it $95 per oz and then the price difference isn’t SO bad. But still. I personally it makes me more likely to consider spending the extra money but even then I’m not sure that the results were THAT MUCH better to make me want to spend the extra money.

Second, I really like the additional ingredients that PC includes like Ferulic Acid, Vit E, Bisabolol and Hexanoyl Dipeptide-3 Norleucine Acetate (which is a tripeptide that can help speed up cell renewal). I didn’t realize until writing up my review that the Obagi ingredient list was so sparse… Now that I see the ingredient list and consider the low pH, I’m not as surprised that I noticed some dehydration after 3 mths of using it.

On that point, I have never experienced dehydration after using PC.

In my Instagram stories I asked you all what you thought in terms of how they compared, and I will include the series of stories of those results below. Keep in mind that when everyone voted, I didn’t disclose what the ya products were.

Finally, I thought I would share how I use my Vitamin C (L-ascorbic acid) serums. So you can find that info below. For what it’s worth, there are many times over the years that I didn’t think a serum faded my pigmentation until I saw the photos. As your skin slowly improves over a number of months, it’s easy to miss the results. So I really recommend trying to take photos when you start a new product and give your skin time to improve! (Patience abs consistency is key).