@greeneyedgirl107 @carlyw13 Having used both First Aid Beauty FAB Skin Lab Retinol Serum 0.25% Pure Concentrate and The INKEY List Retinol Fine Lines and Wrinkles Serum 1 oz / 30 ml on my mostly-dry combo skin, I can say The Inkey List Retinol is stronger than the FAB retinol serum. In fact, I moved up to The inkey List from the FAB serum.
TIL contains 1% RediStar retinol (a stabilized combo of retinol, a vitamin C derivative, vitamin E, and castor oil) plus 0.5% HPR (granactive retinoid). Theoretically, HPR binds directly to retinoic acid receptors in our skin cells, thus it requires no conversion to retinoic acid—unlike retinol which requires 2 conversions before our skin can use it. HPR is also claimed to be gentler than retinoic acid. There aren't yet enough clinical studies on HPR to back the theory behind it, so using it is kinda like beta testing it. 😂 But I had very good results with TIL Retinol for the 1.3 years I used it, especially once I reached nightly use tolerance.
If you want to stick with retinol + HPR: I moved from TIL Retinol to SOBEL SKIN Rx 4.5% Retinol Night Treatment . The 4.5% sounds super scary, but it's not really 4.5% pure retinol. It's a blend of retinol and HPR, and the retinol is encapsulated for gradual time release. This stuff is pricy, but it increased the speed of my skin tone balancing in a noticeable way without drying out my skin. I used it for 5 months or so and still have a bit left in the bottle. Overall, I liked it a lot. If you try it, I recommend starting off with just a couple nights a week at first, even if you're already at nightly use with TIL Retinol—unless you're positive your skin can handle more frequent use of a stronger retinol product right off the bat.
A retinol-only option: For a couple weeks (before I switched to the Sobel Skin serum), I tried a mini of Shani Darden Skin Care Retinol Reform® 0.3 oz/ 10 mL . That's a 2.2% encapsulated retinol serum (no HPR). It also contains 2% lactic acid which is fairly gentle strength for an AHA exfoliant, but I don't like using AHAs more than 2 times a week. That's why I stopped using this Shani Darden serum: I'd rather control how often I use AHAs than have to use one each night I apply retinol. Also, at 2.2% retinol, this is not a low-strength serum: if you try it, slowly build your way up to frequent usage. This stuff can do some serious damage if you rush frequency.
If you're open to other members of the retinoid family: I'm now using Avene RetrinAL 0.1 Intensive Cream. The retinoid in this product is retinaldehyde, which requires just one conversion to retinoic acid. Studies show it works faster than retinol (thanks to needing one less conversion) with possibly less irritation. I've only used it for about a month and my skin's doing well with it so far. It'll be interesting to see how my hyperpigmentation responds to this retinaldehyde serum over more time, compared to the Sobel Skin retinol + HPR serum.
A non-retinoid option to consider: Since you're targeting PIH (post-inflammatory hyperpigmentation, aka dark marks/"scars" left by acne), I'll mention azelaic acid as something you can use while also using any retinoid product. Azelaic acid can address PIH and kill acne-causing bacteria, and can be used daily. You could even use it instead of a retinoid, if all you're really trying to do is lift PIH, but I find it pairs well with retinoids. A dermatologist can prescribe a 20% product, but I like The Ordinary Azelaic Acid 10% Suspension Brightening Cream 1 oz/ 30 mL a lot. A couple times a week, usually when I have active acne, I use Paula's Choice 10% Azelaic Acid Booster instead because it contains a bit of BHA.