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Post in Oily Skin

Glycolic Acid and Vitamin C?

Can I use Vitamin C (in silicone) and Glycolic Acid on the same night?  What about also Granactive Retinoid 2% in Squalane?  Is it too much?  I dont want to use Vitamin C in the daytime because I use Niacinamide... all by The Ordinary BTW...

Re: Glycolic Acid and Vitamin C?

Depends on how sensitive your skin is.  I've used AHA's with Vitamin C in the morning followed by SPF with no problem. I currently use a BHA, Niacinamide, and Vitamin C in the morning with no problems.  The key is to gradually introduce products into your routine.  Using an exfoliant generally increases the effectiveness of serums that follow it.  Check out David Lin on youtube.  He's a dermatologist and gives honest advice about what's effective and what's not.

Glycolic Acid and Vitamin C?

I just started using both at night too, and I read that chemically, you can use them one after the other and they won't compromise each other but it is burning a bit and stinging. some blogs say that the glycolic acid actually enhances the effectiveness of the vitamin c by prepping the skin's ph level. so besides irritation, most sources say yes, and I'm hoping to see the irritation lessen over time. do not use vitamin c or glycolic acid on the same night as retinol treatments though. way too much drying and irritation.

Re: Glycolic Acid and Vitamin C?

@Manwitch  You can use glycolic acid or vitamin C with retinol, if your skin can tolerate it. Some of that depends on the strength (%) of your AHA, vit C, and retinol. I routinely layer an OTC retinol over either a 10% AHA or 2% BHA leave-on exfoliant at night. I use a vit C serum in the morning. Some mornings I also use my leave-on AHA exfoliant, layering it with vit C. And my usual AM and PM moisturizer contains vit C. 


As others have mentioned in this thread, the key to layering AHA and retinol is to introduce them slowly and individually to your routine. I always recommend starting with the AHA: use it once or twice a week for 2 weeks, then increase usage if you want. A few weeks later, introduce the retinol once a week and don’t use it on an AHA night; you may want to decrease your overall AHA frequency during your retinol intro period. Once your skin’s fine with retinol and you can use it more nights a week, try layering it over your AHA. You can also just use your AHA in the morning and retinol at night—but even in that scenario, slow introduction will help. 


You might need a lower strength AHA or vit C if they’re making your skin burn and sting. Did you introduce them to your skin one at a time, or did you layer them right off the bat? 

Re: Glycolic Acid and Vitamin C?

Yes, you can use Glycolic acid and Vitamin C...usually in that order.  I was watching Hot and Flashy on YouTube.  Angie's father is a chemist and she really does her research.  Are you sure you can't switch and do the Glycolic/Vit C in the AM and then do the niacinamide in the evening?  I do that and it seems to work just fine.

Vitamin C breaks down when exposed to the sun, and most s...

Vitamin C breaks down when exposed to the sun, and most sources say evening makes it more effective, both cause it isnt being weakened by sunlight and because your skin absorbs it better. niacinamide in the morning makes sense too because it kinda preps your pores for a long day of sweating and oil and sebum.

@quspork Well at least the higher concentrations of Vitam...

@quspork Well at least the higher concentrations of Vitamin C do, according to Vogue and few other places, but I guess this is only when not armed with an SPF then? As long as we use an SPF, it'll increases SPF effectiveness and still retain its strength? "Layer It Under SPF Unlike hydroxyacids or retinol, vitamin C does not make the skin more vulnerable to sunburn. That being said, the most potent forms of vitamin C are vulnerable to light exposure, and therefore the use of vitamin C must be in conjunction with broad-spectrum UVA/UVB coverage. The good news is that, when layered underneath sunscreen with a minimum of SPF 30, vitamin C protects the skin even further. "Think of it as a safety net to help neutralize free radical damage that can occur from UV light penetration despite our best protection efforts with sunscreen," says Zeichner."

Re: @quspork Well at least the higher concentrations of Vitam...

@Manwitch Anyone who is using any sort of active ingredient (vitamin C, AHA, BHA, retinol/oid, etc) should absolutely be wearing a standalone sunscreen (30 spf or above) every day. If you're interested in the scientific studies behind using topical vitamin C, I highly recommend the blogs by Labmuffin and Kind of Stephen. Both are great resources for more information and provide links to the actual academic studies. 

Re: @quspork Well at least the higher concentrations of Vitam...

@Manwitch  @quspork  I’ll take that a step further: anyone who uses ANYTHING—or even nothing—on their face should use a sunscreen with a minimum SPF of 30 every day, all year long. (I suppose the only exception is covering/shading your entire face with a wide-brimmed hat, ski mask, etc.; some folks have bad or allergic reactions to many sunscreens.) Not using an AHA doesn’t mean you can skip sunscreen. Smiley Happy 


Folks should also apply sunscreen to exposed skin anywhere else on their bodies. If you use an AHA body lotion (I use one on my elbows and forearms now) or a BHA body acne product on skin that’s exposed to the sun, that’s all the more reason to also use a body sunscreen. 

Re: @quspork Well at least the higher concentrations of Vitam...

Absolutely, @WinglessOne. Everyone should be wearing adequate sunscreen protection each day. That's exactly what I was getting at. Smiley Happy

Re: @quspork Well at least the higher concentrations of Vitam...

@WinglessOne  or if you're a hermit? lol. Smiley Tongue  the NW is cloudy most of the year, and they say you're supposed to wear it even if it's cloudy...but what if it's raining?  I do like big umbrellas, but if you don't have one (they can get kinda heavy and big to carry around, and try not to hit people with), or are biking, I feel like why bother putting anything on if it's just going to get wet...?

Re: @quspork Well at least the higher concentrations of Vitam...

@treestar86  If rain rinses your sunscreen away, reapply it once you get someplace dry. Smiley Happy You can also use a water-resistant sunscreen. Anytime you’re in water at a beach, lake, or pool during daylight hours, you still need sunscreen and you’ll probably have to reapply it after a couple of hours. 


Even on rainless days when you’re not lounging in water, you should reapply sunscreen every few hours. If I’m wearing any makeup besides brow pencil and lipstick, I carry SUPERGOOP! - Invincible Setting Powder SPF 45 in my bag so I can re-up my sunscreen. Otherwise, I carry SUPERGOOP! - Unseen Sunscreen Broad Spectrum SPF 40 in my bag to reapply throughout the day. 


And yep, you need sunscreen even on cloudy days. Always wear your sunscreen! 

Re: @quspork Well at least the higher concentrations of Vitam...

@qusporkI thought vit. c was like the opposite of acids + retinol, and beneficial to use during the day.  so I'm confused when some people say you should wear sunscreen when using it (even though you're supposed to wear it all the time anyway...), bc I don't think I've seen that on any vit. c products, whereas most acids + peels, etc., have that warning about wearing sunscreen and avoiding the sun for 2 weeks afterwards.

Re: @quspork Well at least the higher concentrations of Vitam...

@treestar86  AHA exfoliants in the US have the “sunburn alert” warning on their labels because the FDA strongly encourages it. They hope it’ll make more consumers aware of the heightened sun sensitivity caused by AHAs. If you’re curious, you can read the history of that warning and the FDA’s guidelines at their site: just Google “fda sunburn alert” and it’ll come up as the first result. 


Vitamin C doesn’t require that kind of warning because it doesn’t cause sun sensitivity—at least not according to any study I’ve read. The main reason to apply sunscreen over vit C is to boost sun protection. A doctor once told me vit C should be applied only at night because UV light depletes skin’s vit C levels. But other docs I’ve asked have recommended using it in the daytime (one doc tells patients to think of sunscreen and vit C as The Wonder Twins, which is a perfectly valid excuse to say “Wonder Twin powers, activate!” when applying sunscreen in the morning 😂), and a couple docs even suggested using it morning and night as long as the percentage wasn’t too high. 

Re: @quspork Well at least the higher concentrations of Vitam...

@WinglessOne wrote:

Vitamin C doesn’t require that kind of warning because it doesn’t cause sun sensitivity—at least not according to any study I’ve read.

that's what I thought.  and they say it fights free radicals (does that make it an antioxidant?), so that's another reason I thought it was better for day.  I usually use it during the day, and other acids/peels at night, bc they usually say to use them at night.

Re: @quspork Well at least the higher concentrations of Vitam...

@treestar86  Yep, vitamin C is an antioxidant. So is retinol/retinoid (vitamin A). 


I usually do my AHA/BHA exfoliation at night too, but sometimes I do it in the morning—depending on what I did to my face the previous night and/or my skin’s condition. I always use my vit C serum in the morning. Lately I’ve considered also using it at night to see what happens with twice-daily usage. I might start that in a few weeks, once my skin’s calmed down from a recent product test gone bad. 

Re: @quspork Well at least the higher concentrations of Vitam...

@WinglessOne  hmm, well that's confusing since it has the opposite of vit. c's beneficial daytime properties.  I have a night cream that I noticed has vit. A, but it doesn't have the sunscreen warning...

Re: @quspork Well at least the higher concentrations of Vitam...

@treestar86  All antioxidants don’t target the same things, just like all peptides don’t target the same things. They may have some of the same end results (for instance, antioxidants’ common high-level result is skin protection), but they achieve them in different ways. Otherwise, we wouldn’t need a handful of different antioxidants in any skincare product; we could just use a single antioxidant and call it a day. Smiley Happy 


I once found a good write-up of antioxidants: what they are, what different ones do, etc. I’ll look for that later on for you, or maybe someone else in this thread can give you a good reference source. It’s interesting and helpful info. 


Contrary to popular belief, you can use OTC retinol during the day. But you must also use sunscreen with it to keep it stabilized. You should use sunscreen each day anyway, no matter what else is on your face. But yeah, you can use an OTC retinol and vit C in the morning, then apply an SPF 30+ sunscreen (over your moisturizer, of course). I prefer to use retinol at night because I like to keep my AM routine as brief and efficient as possible—the less AM steps, the better for me. 

Re: @quspork Well at least the higher concentrations of Vitam...

@WinglessOne  ahh, yes that makes sense - kinda like vitamins I guess.  I just pictured a generic 'antioxidant skincare' product, lol. Smiley Tongue


yeah when I first got/started using acids, I was like "yayy, this'll make my face look better so I'll wanna go show it off" lol...didn't even notice the sunscreen warning for a while.  so I started checking more, and was surprised that that one didn't have it.  so I guess you have to look at the ingredients and know something about skincare.

Re: @quspork Well at least the higher concentrations of Vitam...

@treestar86 K-beauty considers vitamin C to be an "active" in the same category as chemical exfoliants like AHAs and BHAs because it contains an active ingredient that is one of the workhorses of a routine, as far as actually making changes to the skin. Everyone should be wearing sunscreen, so I think that's the biggest part of why it keeps getting said, but also noting that vitamin C is an anti-oxident and has a positive boosting effect on sunscreen that's why it's often recommended for morning use. 

Re: Vitamin C breaks down when exposed to the sun, and most s...

@Manwitch Vitamin C is great to use in the morning. It does not break down in sunlight and actually boosts the effectiveness of sunscreen. 


@VALEJHUSEY There's no reason to not use vitamin C and niacinamide together. Some people experience a harmless flushing, but that's fairly rare. The studies about each cancelling out the other's effectiveness have been widely debunked. In regards to the other ingredients, it's mostly up to your skin and how it reacts. You can use the vitamin C (if you prefer to keep it in the evenings) with the glycolic acid, but I would recommend alternating nights between that combo and the retinoid. Either way, with all those actives, make sure you're using moisturizer both day and night and a standalone sunscreen every morning to avoid sun damage. 


If these ingredients are new to you, I'd definitely recommend introducing them slowly one at a time. Jumping in to this type of routine if you are unfamiliar with actives can lead to over-exfoliation. 

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