The How & Why of Serums (Skincare Update Pt. 2)

The How & Why of Serums (Skincare Update Pt. 2)
The How & Why of Serums | Little Henry Lee

In case you missed reading about Part 1 of my skincare routine I’d recommend checking that out to get the full picture in combination with this post. In Part 1 I mentioned that I was going to talk about serums separately because they deserve a post of their own, and you’d better get yourself a cup of tea because we’re diving deep. Along with reviews of the products I’m currently using, I'm also talking about how I use them, as well as the strategy behind my routine and why I use the ingredients that I do. I’m a firm believer that most of your money should be spent on the serum stage, and on products that contain key ingredients with proven results. Now, obviously I don’t use all of these serums on my face morning and night, but I do think it’s important to have a good combination of them all. I like to think of skincare as food for my skin, so I try to make sure I've got a well-balanced routine that provides my skin with everything it needs to look its best.

Although it’s not part of the serum stage, I wanted to include a quick note on SPF. While some of the ingredients I talk about will make you more susceptible to sun damage, I personally would recommend using an SPF every day regardless of what other skincare you’re using. You can use all the expensive serums you like to try and repair existing damage, but it's going to be a waste if you're not protecting your skin from getting damaged in the first place. Although it's not sexy and generally isn't marketed as an anti-ageing product, that's exactly what sunscreen is, so even if you don’t use any serums, I’d consider SPF the bare minimum.

Key Ingredients

For several years I’ve focused on incorporating certain ingredients into my routine because of their ability to address my particular skin concerns. Some of these ingredients are not-negotiable, and others I consider nice to have, meaning I prioritise them less but don’t ignore them altogether. The way to figure out which ingredients to prioritise is to consider what your main skin concerns are and then build a customised routine from there. Here’s what works for me: 

Nice to Have

  • Hyaluronic Acid

  • Peptides

  • Salicylic Acid (BHA)

Not Negotiable

  • AHAs

  • Retinoids

  • Vitamin C

  • Niacinamide

My primary concern is preventing the early signs of ageing (all of them except salicylic acid). My secondary concerns are fading post-acne pigmentation (everything under not-negotiable), dealing with congestion and texture that I get in my chin area (niacinamide), and handling the occasional breakout (salicylic acid). But this is just what works for me - if you’re 20 and mostly concerned with acne, you may only want to focus on BHA products and maybe include niacinamide and AHAs. If you have sensitive skin, you may not use AHAs or retinoids very often. If you have dry skin and never break out then hyaluronic acid will probably be more important to you and you won’t need salicylic acid. If you have actual skin conditions you need to treat, like eczema or rosacea, then that's a whole other ball-game and I'd suggest seeing a dermatologist.

Based on all the research I’ve done, I would suggest that if you’re concerned with preventing and repairing the signs of ageing, then you’ll need a combination of all of these ingredients (minus salicylic acid, plus SPF) to give yourself the best chance possible. Of course you don’t have to do all of this, no one has to do anything, but if you want to consciously try to do as much as you can (i.e. if you’re me) then this is the way. I would definitely suggest thinking about which ingredients sound like they would be best for your skin and prioritise them accordingly. In case you’re not sure what all these ingredients do or why they’re in my routine, I’ve included a brief summary with each one to use as a guide, but I’d suggest doing your own research as well. Please keep in mind once again that I'm talking about my routine and what works for me, I'm not trying to dictate a set of rules to you because it's a very personal thing and I don't want to sound like I'm the almighty skincare Lord, or like I’m shoving anything down your throat. I’m just a girl who gets super nerdy about the shit I’m into.

The How & Why of Serums | Little Henry Lee

Vitamin C

WHAT IT DOES: Provides protection against free radicals, helps fade pigmentation and boosts collagen production. Collagen is what keeps your skin elastic and firm which is why it’s so crucial for young-looking skin.

HOW I USE IT: Because certain ingredients increase your sensitivity to the sun, I’ll generally use them at night time. Vitamin C isn’t one of those ingredients, so the easiest way for me to fit it into my routine is to use it in the morning when I have less to choose from.

WHAT I'M USING: I won’t go on about my vitamin C products too much as I pretty much covered it all in my post about The Ordinary since I’m now using their Ascorbyl Glucoside 12%. I introduced it into my routine as a replacement for the Hylamide Vitamin C Booster (AU), and both products are under the Deciem umbrella.

The Hylamide serum has a thin, watery texture that feels slightly oily to the touch, although the product itself is water, oil and silicone free - in fact, it only has four ingredients! Whatever it is, it sinks into the skin immediately and I was definitely happy while using it, and will probably return to it again in the future as it’s stronger than the one I’m using from The Ordinary. The Ordinary one layers well with the other products in my routine and I’m fine with using it for now, but I’m not in love with it.

Before I made the switch from Hylamide to The Ordinary I had planned to use my mini of the Drunk Elephant C-Firma Day Serum (AU) which I’ve seen a lot people raving about. Unfortunately it had gone bad from the first pump (it came out dark orange instead of really pale) so I had to give that one a miss. Honestly it’s made me hesitant about trying it again because it’s not cheap and I would be pretty upset if I bought a full sized bottle and it went bad half way through.

The How & Why of Serums | Little Henry Lee


WHAT THEY DO: AHAs (alpha-hydroxy acids) gently exfoliate the skin by “ungluing” dead skin cells, this can also be referred to as boosting cell turnover. This evens out skin texture, helps pigmentation fade more quickly, and by getting dead skin out of the way they also help other ingredients to penetrate more easily.

Glycolic and lactic acid are the two most common AHAs, the main difference being that glycolic has smaller molecules, so it penetrates the skin more quickly, which means it can feel stronger, and that it has a greater potential to cause irritation in those with sensitive skin. Lactic, on the other hand, has larger molecules so it’s better for sensitive skin, and it’s generally more hydrating so it’s great for mature and/or dryer skin as well. I personally get great results from both, either separately or combined in the same product.

HOW I USE THEM: Because they boost cell turnover, AHAs make your new, fresh skin more susceptible to sun damage, so although I use a gentle AHA toner in the morning, I save these stronger treatments for night, and I always use an SPF during the day. Side note: if I know I’m using a stronger acid treatment I’ll probably skip my acid toner that night, and maybe the morning after too, depending on how my skin feels and the strength of the product I've used.

WHAT I'M USING: I always have some sort of acid treatment in my routine because I love the results I get from using a stronger treatment a few nights a week. The three products I’ve used most recently are the REN Wake Wonderful Night Time Facial (AU), the Drunk Elephant T.L.C. Framboos Glycolic Night Serum (AU) and Sunday Riley's Good Genes (AU). 

The REN and Sunday Riley products are both lactic acid based, while the Drunk Elephant contains mostly glycolic and salicylic, with lactic coming last out of those 3 on the ingredients list. Speaking of the ingredients list, it’s generally accepted that brands list a product’s ingredients in order of the % included, the same as food labelling. So Drunk Elephant claim that this serum contains a 12% AHA blend of glycolic, tartaric, lactic and citric acids, and a separate 1% of salicylic acid.

The How & Why of Serums | Little Henry Lee

When you actually look at the ingredients list, the first three are water, glycolic acid, then salicylic acid, which means anything that comes after salicylic acid is in there at less than 1%. So technically there might be a 12% combination of AHAs in there, but chances are 10-11% of that is all glycolic. That’s not to say it’s a bad thing, I love glycolic acid, I just think it’s a bit misleading to talk about this powerful AHA blend when really it’s glycolic doing all the work.

In saying that, I do respect that they talk about the % of acids used because most brands don’t even do that (SR & REN don’t), so at least you know what you’re working with. As for the results, while it’s not drying in any way, I don’t find it to be quite as hydrating/plumping as the other two, but if acne is a concern for you I think this would be the one to go for because of the salicylic acid, which the other two lack.

However, if you have dry, mature or sensitive skin you’ll probably enjoy the REN or Sunday Riley treatments more because of the focus on lactic acid. I haven’t personally experienced any irritation from using any of these products, but keep in mind that my skin isn’t sensitive, and it’s used to regular exfoliation. I’ve said before that I think the REN treatment is incredibly similar to Good Genes but half the price and I stand by that. They have a very similar texture upon application, and I get comparable results from them, which of course is the most important thing. They’re both very gentle and I can use them several nights in a row, although I don’t necessarily do that with the Drunk Elephant serum. I don’t feel that I need to with the DE, and I’d guess that at 12% it’s probably stronger than the other two.

Between the three I probably wouldn’t repurchase the Drunk Elephant as I’m happy using a salicylic acid spot treatment when the need arises, so for what amounts to a mostly glycolic treatment, I feel like I could probably find better value elsewhere. But as I said earlier, if you’re particularly concerned with acne this would be the one to go for out of the three I'm talking about in this post. The REN is definitely the best value for money, but I do have a soft spot for Good Genes and I think it’s really lovely, so if you can afford to treat yourself then this is a beautiful option. If you’re choosing between the two, I would say go with what your budget allows, because I would confidently recommend both of them.

The How & Why of Serums | Little Henry Lee


WHAT IT DOES: Retinoids are cell-communicating ingredients while also being antioxidants. They protect your skin from free radical damage, encourage the repair of your damaged cells, and boost cell turnover at the same time (though at a deeper level than AHAs). There's a reason retinoid products are prescribed by doctors and dermatologists, it's because they work.

HOW I USE IT: Because it can make you more susceptible to sun damage, as with AHAs, I use my retinoid product at night. I also like to alternate the two because I don’t want to overload my skin by using them on the same night and potentially cause unnecessary irritation.

WHAT I'M USING: A bit of background first - there are several forms of retinoids (retinol being one of them), and my understanding is retinoid is the correct umbrella term for the family, although previously I’ve (incorrectly) used the word retinol in its place. If you delve into the different types of retinoid ingredients it can all get very confusing very quickly, so in the interest of not making this post much longer than it already is, I’m going to try and keep things simple.

Retinoic Acid (or Tretinoin) is one of the strongest retinoids available because it’s ready for the skin to use, so it gets to work straight away, however it’s only available in prescription strength products and it’s also pretty likely to cause a significant level of irritation, which is its biggest drawback.

Ingredients like Retinol and Retinyl Palmitate undergo metabolic conversions on the skin to become Retinoic Acid, which the skin can use. This conversion process means they are far less likely to cause irritation, but they are also less effective in terms of their positive results. As for the product I’m using right now, it’s Sunday Riley's Luna (AU) from this double pack (AU), and it contains Hydroxypinacolone Retinoate. HPR has all this buzz around it because it’s an ester, which means it acts like Retinoic Acid on the skin, but it’s a lot gentler and shouldn’t cause any irritation. Of course being a newer ingredient, there is far less research available on HPR than there is on Retinoic Acid, but there are plenty of companies who believe in this ingredient because it’s in all 3 of the products I’m going to mention.

I have to say, I was pretty skeptical going in to using Luna. When it first launched there was SO MUCH HYPE that if anything I was slightly prejudiced against the product, because surely it couldn’t be that amazing? I think a lot of people perhaps hadn’t used any kind of retinoid before so they were blown away by the results, and I also think a good bit of it was people jumping on the bandwagon, so I took it all with a grain of salt. As mentioned, Luna contains HRP, and the product I was using before was Indeed Labs' Retinol Reface (AU) which contains both HPR and Retinol. A product I haven’t tried but is very popular at the moment is The Ordinary’s Granactive Retiniod 2% Emulsion, which also contains both HRP and Retinol. Neither Sunday Riley nor Indeed Labs disclose the percentage of retinoid ingredients in their products, so I can’t say which of the 3 is strongest. But I have never experienced any irritation from using either Luna or Retinol Reface, and could comfortably use them several nights in a row without any adverse effects.

The How & Why of Serums | Little Henry Lee

Beyond HPR, Luna has a pretty clean ingredients list, with the first four being cold pressed avocado, grape seed, blackberry and chia oils which are all sources of antioxidants. It also contains blue tansy and several forms of chamomile oil, all of which have strong anti-inflammatory properties which should help soothe and counteract any potential inflammation from the HPR. The only part that I take issue with are the two dyes included at the end which are responsible for the deep blue colour.

While I don't think the dyes are going to kill you, it's just a bit gimmickey and they're completely unnecessary to the formula. Though I've read that the brand added colouring to remind people that it's meant for night-time use, but the dyes could definitely put some people off from purchasing it. Superficially, it’s a beautiful oil to use and I’m really enjoying it, even if my boyfriend says it makes my face smell like porridge (lol). The scent isn't pleasant but I don't find it overly invasive and if it helps, that's just the natural scent of the ingredients as there's no added fragrance. It also definitely works for me - I see results from the HPR in the form of smoother, brighter, plumper skin in the morning, and of course retinoids work in both a preventative and a long-term capacity as well. 

The How & Why of Serums | Little Henry Lee

So rather than asking is this product worth the hype, I think a more nuanced way to look at it is to consider what aspects of a product contain the most value for you. If your main priority is results, then yes Luna gives them, although it’s far from the strongest retinoid product money can buy. It doesn’t vastly outperform the budget options, and nothing that’s over the counter is going to be stronger than prescription strength. But if you want something that’s entry level in terms of efficacy (not price) or if you have sensitive skin and are worried about having a reaction, then Luna could be great for you as it’s a gentler option that’s very unlikely to cause irritation.

If convenience is something you want, then Luna not only acts as your retinoid treatment but it’s also a hydrating oil with antioxidants, so it does double duty as I don’t need to use a moisturiser or another oil on top. If you hate the thought of a 10 step evening routine you may see the value in a product that does a few things at once and saves you some time. If you’re on a budget, Luna is up there in price, and there are definitely products that will give you similar results for a lot less money, especially now that a brand like The Ordinary is around, though of course their formulas are generally not as cosmetically pleasing. I don’t think the formula and the price of Luna are particularly well-aligned as the four oils that are the base of the product aren’t overly expensive, so I do think there is a pretty big markup here. In saying that, if luxury is something you prioritise because it adds to your experience when using a product, then Luna has that in abundance. It just comes down to what you want in a product because if it ticks all your boxes then you’ll be a happy camper.

So would I buy it again? Well I can’t deny that it works for me and my skin looks great the morning after I’ve used it. In fact, The Ordinary’s Niacinamide 10% + Zinc 1% underneath Luna is my current dream team. But efficacy is probably my highest priority and I will most likely look for something a bit stronger than this for my next step as prevention is better than a cure. But if you couldn’t tell from the length of this post, I’m a bit more enthusiastic about skincare than your average person. If you have the budget to buy Luna and love a bit of luxury then I don’t think you'll be disappointed, and I will definitely use and enjoy every drop.

The How & Why of Serums | Little Henry Lee

Niacinamide (Vitamin B3)

WHAT IT DOES: it’s cell-communicating, so it encourages your cells to produce more collagen and ceramides which help the skin retain moisture, while also helping improve the appearance of fine line and uneven skin tone, and it can help with acne and skin congestion.

HOW I USE IT: I’ll use it either morning or night, and so far it’s layered just fine with everything else in my routine.

WHAT I'M USING: Again, because I spoke about Niacinamide 10% + Zinc 1% in my post about The Ordinary, I’ll keep this brief. But I do think it’s worth reiterating that I love this product and that using this has convinced me that niacinamide needs to be on my “not-negotiable” list. I’ve used products that contained niacinamde in the past, but none at this kind of concentration, and none that put the ingredient front and centre in the product. My skin has definitely benefited from me including this in my routine and I’m really glad that I tried it. I find that this product evens out my skin texture and takes care of the little bumps/congestion I would get around my chin/jawline when nothing else seemed to work. And as I mentioned earlier, layering this with Luna at night leaves my skin looking beautiful in the morning. I’m just coming to the end of this bottle now and I've got a backup waiting to go.

The How & Why of Serums | Little Henry Lee

Hyaluronic Acid & Peptides

WHAT THEY DO: Hyaluronic Acid is a non-exfoliating acid that’s naturally found in the skin and that really effectively attracts and holds moisture. It’s not anti-ageing in the sense that it protects your skin or helps it repair itself, but hydration is absolutely key to plump, youthful looking skin. By boosting hydration, HA provides virtually instant, visible results in the form of softer, smoother skin with diminished fine lines & wrinkles, and that’s why it’s such a popular ingredient.

Peptides are cell-communicating ingredients that tell your cells to produce more collagen, and as mentioned previously, collagen is what keeps skin elastic and firm.

HOW I USE THEM: I’ve grouped these two together because the product I’m currently using incorporates both of these ingredients. I find that’s an easy way for me to cut down on the number of products I use without compromising on the ingredients my skin is getting. As with vitamin C, neither of these ingredients make your skin more sensitive to the sun, so I’ll typically use this in the morning because I feel like the extra boost of hydration also makes my makeup sit nicer. I may use it at night if I feel like I’ve been going hard with the acids & retinoids and want to give my skin a break, or perhaps I’ve just used a mask and want something gentle to finish up. I always use this serum before moisturiser because that’s how HA works best, and because my other serums are, for lack of a better term, more “active” so they go on my skin first.

WHAT I'M USING: Although I don’t have dry skin, I still like having a hyaluronic acid product in my routine for added hydration, and for all the reasons I mentioned above. Although I don’t prioritise HA as much as other ingredients because of my skin type, I still make a point of having it in my routine because I love the effect it has on my skin. Right now I’m coming into my first winter in a much harsher climate than I’m used to, so I have a feeling I’m going to be relying on HA a whole lot more in the coming months. At my age I don’t think peptides are an absolute must, they’re more of a long-game thing and don’t really deliver results that you’re going to notice. But I figure if I’m going to have a hydrating product it may as well have peptides in there as well because they can’t hurt. For this purpose I was using the Hylamide SubQ Anti-Age Serum (AU) and have replaced it with The Ordinary's Buffet. I discussed the two of them in my post about The Ordinary as well, so I won’t repeat myself too much, but I definitely prefer the formula of the Hylamide as it’s more pleasant to use and the brand also says themselves that it’s a stronger product. In saying that, Buffet  is significantly cheaper (about 1/3 of the price) so at this stage I don’t know what I’ll be purchasing next, but if you’re on a budget Buffet is probably the best value for money out there. 


The reason I talked earlier about priorities is because the ingredients that are high priority for me are the ones I’m going to apply to my skin first. However, you also should generally be layering products from thinnest to thickest texture as things like oils and silicones in products will stop whatever you put on top from penetrating. So here are a couple of examples of how I might layer my products (though I do also factor in how my skin is feeling at the time): 

The How & Why of Serums | Little Henry Lee

Day 1:

Morning: Cleanse, Acid Toner, Hydrating Toner (spray), Eyes, Vitamin C, Buffet, Moisturiser, SPF

Evening: Double Cleanse, Acid Toner, Hydrating Toner (spray), Eyes, Niacinamide, Luna

Vitamin C goes first in the morning because it’s more important to me and because the HA in Buffet works best directly under moisturiser. Niacinamide is first in the evening because Luna is an oil, so there’s no point adding a water-based serum on top. If I were using a thinner textured retinoid then it might go first, it depends on the product formulation. I also don’t need to put anything on top of Luna because the oils in the product are hydrating enough.

Day 2:

Morning: Cleanse, Acid Toner, Hydrating Toner (spray), Eyes, Vitamin C, Niacinamide, Moisturiser, SPF

Evening: Double Cleanse, Hydrating Toner (spray), Eyes, Drunk Elephant, Buffet, Moisturiser/Oil

Vitamin C goes first in the morning for the same reason as above (niacinamide is only newly on my not-negotiable list so it’s still prioritised less than vitamin C). I skipped my acid toner at night because I’m using Drunk Elephant, which is a stronger AHA treatment, so I don’t need both. Buffet goes after Drunk Elephant because DE is more important, and because again, the HA in Buffet works best under moisturiser.

How you use and layer your products comes down to formula just as much as your priorities, and obviously how many products you’re juggling. If you’re not using say, a retinol or niacinamide, that makes things a lot simpler and you may have the same morning and evening routine every day. If you have sensitive skin you may prefer to use Buffet under the Drunk Elephant to soften its effects to avoid irritation. Tenniel wrote a great post recently about how to layer your skincare and the idea of waiting for your products to sink in before applying the next one.

I personally just throw it all on there because that’s how I’ve always done it and it’s worked for me, but it’s definitely something to consider if you don’t think your products are working as well as they should, or perhaps if they’re working too well and are irritating your skin. There are things like this that you can adjust within your routine to make sure you’re getting the best out of your products. The most important thing is to listen to your skin, see how it reacts to what you’re putting on it and then find a routine and products that work for you.