7 types of Vitamin C compared – which one is right for your skin?

If you’ve been reading this blog long enough or follow me on Instagram, you know my woes with Vitamin C. It’s an incredibly powerful skincare ingredient, yet my skin just doesn’t quite react to it like others do. Is it the type of vitamin c I’m using? Is it the formula? All this thinking led me down the rabbit hole of hours of reading and research, and of course, a blog post with all my findings.

Before we look at all the different forms of vitamin c, let’s take a look at why this ingredient is beneficial for our skin:

• Promotes collagen synthesis. As we get older, the collagen in our skin starts breaking down and the there’s a decrease in production levels, which means we start seeing fine lines, wrinkles, and sagginess!
• Protects from and treats UV damage. While by no means a replacement for sunscreen, vitamin c can protect against the free radicals from UV exposure and reverse some of the damages caused by too much fun in the sun.
• Reduce hyperpigmentation and dullness by decreasing melanin formation. It works even better when paired with other brightening ingredients!
• Is anti-inflammatory. It inhibits the protein complex that begins the inflammation process, making it great at healing acne and preventing post-inflammatory hyperpigmentation (source).
• Promotes a healthy skin barrier. A study found an increase in ceramide levels when vitamin c levels increased as well

Yep, list any of your skincare woes and vitamin c will pretty much takes care of it, plus it has a ton of studies to back up its claims. Now the question is, what are the differences between the various forms, and is one better than another?

Ascorbic acid (AA)

The most well researched form of vitamin c and the most potent. Other forms of vitamin c often need to be converted to ascorbic acid first to achieve the benefits. A couple things to keep in mind:

• It’s notoriously unstable. Exposure to air, light, and heat will cause AA to start oxidizing. Adding in vitamin E and ferulic acid can help stabilize AA, as can using an opaque and airtight container. Formula and packaging is key when using AA!
• It’s water soluble and requires a low pH ( > 3.5) for optimal skin penetration.
• It can be irritating due to the low pH formula it’s in, making it less ideal for those with dry/sensitive skin
• The potency of AA increases as you increase the concentration, but only up to 20%.

Ascorbic Acid products I’ve tried:

Magnesium Ascorbyl Phosphate (MAP)

This is a stable of vitamin c that needs to be transformed into ascorbic acid by our skin. As a result, it’s not as potent, but also much gentler on the skin.

• Still water soluble but no longer requires a low pH to be efficient.
• Delivers all the benefits of AA but because it’s weaker, it’s often paired with other antioxidants and brightening ingredients to boost its efficacy.
• One study found that a concentration of at least 10% MAP is required for brightening effects (source).
• Considered a “whitening” (which really means brightening) ingredient by the Department of Health in Taiwan, suggesting that enough research was done to in terms of MAP’s brightening properties (sadly my Googling abilities weren’t good enough to find all these studies)

MAP products I’ve tried:

Sodium Ascorbyl Phosphate (SAP)

SAP and MAP are very similar in that:

• Both are water soluble, not low-pH dependent, and have same benefits as AA, but not as potent nor as irritating on the skin.
• Both are often paired with other key ingredients to improve efficacy.
• One study actually found SAP to be even more stable than MAP (source).
• Several studies show that SAP has an antimicrobial effect and can be a good option for treating and preventing acne (source). Don’t forget vitamin c in general is anti-inflammatory, which is also beneficial for acne-prone skin.

SAP products I’ve tried:

Ethyl Ascorbic Acid (EAA)

• Aka 3-O-ethyl-L-ascorbic acid, an extremely stable form of vitamin C.
• Several studies have been done on EAA’s brightening effects, which show promising results (source). One study showed that it has superior brightening abilities compared to other vitamin c forms, even AA (source)
• There have been a few reports of allergic reactions to EAA, but in my opinion this is more of a YMMV case than an actual issue with EAA.

EAA products I’ve used:

Ascorbyl Glucoside (AG)

• A water-soluble form of vitamin C that’s more stable than AA (at this point just assume every other vitamin c form is more stable than AA).
• Non-irritating. What else is new?
• Can be converted into AA in our skin, thus delivering all the benefits of vitamin c but at a much lower potency.
• Considered a “whitening” (which really means brightening) ingredient by the Department of Health in Taiwan, suggesting that AG’s brightening properties are well studied.
• One study showed that AG significantly reduced hyperpigmentation when used with an absorption enhancer like ultrasound radiation (source) and another study showed the same results when used with a full-face iontophoresis mask (source).

AG products I’ve used:

Ascorbyl Palmitate (AP)

• A fat soluble form of vitamin c that penetrates the skin more easily than other forms (source).
• More stable than AA but less stable than MAP and SAP.
• Gentler than AA, but not as potent. You need a lot more AP to get the same results.
• Can help control sebum production when used with SAP, making it a good option for oily and acne-prone skin (source).

AP products I’ve used:

Ascorbyl Tetraisopalmitate (ATIP)

• Aka VC-IP, Tetrahexyldecyl Ascorbate, or THD Ascorbate.
• Fat soluble, gentle, and very stable. It can also penetrate into the deeper layers of the skin.
• Several clinical trials showed significant improvement in skin texture and tone after using products featuring (not not limited to) ATIP (source , source, source).
• It can stimulate the production natural moisturizing factors, which allows our skin to better to absorb moisture from the body, keeping it well hydrated (source).
• One study found that ATIP is actually better at increasing collagen synthesis than AA (source).

ATIP products I’ve used:

Key takeaways

Kudos to you if you’ve read through all that, because I know that was a lot of info, but if you haven’t, here’s a quick summary:

• Formula is key when selecting a vitamin c product. For AA-based products, the pH needs to be < 3.5. For all other forms, you’ll want to see it in a mix with other antioxidants and beneficial ingredients.
• As with all actives, you’ll want to see vitamin c near the top of the ingredient list. Remember that the derivatives need to be converted to AA first, so if you’re getting a peanut amount of that, you probably aren’t getting any of the vitamin c benefits.
• When it comes to potency, you can’t beat AA. However, you’ll want to weight the pros and cons to see if it’s really the right form for your skin type and skincare habits. Sensitive skin will want to try the other gentler forms, or at least start with a very low % of AA.
• SAP and MAP are very similar, both provide the same benefits as AA but at a lower potency, with less irritation, and more stability.  They’re also relative well researched compared to other forms of vitamin c (asides from AA).
• Oily and acne prone skin should consider SAP and AP for its anti-microbial and sebum control properties.
• Look for EAA or AG if you want to brighten your skin tone, as both have specific studies done in regards to their brightening properties. I prefer AG, but YMMV.
• Always wear sunscreen, especially if you use AA as that can make your skin more sensitive!

Hope you found this post helpful, and let me know which vitamin c product(s) you swear by!