Your Guide to Vitamin C Derivatives

Vitamin C is touted as the panacea for virtually every skin concern — uneven tone, rough texture, fine lines, blemishes, scars, dullness — you name it. It’s the golden child of skincare. Like all good things, it only lives up to its super-ingredient greatness if it’s the real deal — pure, potent, and has enough to pack a punch. Here are several factors to consider on your quest for the bright stuff. 

Vitamin C Concentration 

Too often consumers are eager to apply vitamin C products to their skin but fail to check how much is included. For example, brands can state the Vitamin C included is 100% pure but offer less than 5% of the ingredient, deeming it totally ineffective. It’s like making a smoothie with two organic blueberries. Sure, they’re an awesome superfood but you haven’t included nearly enough to give your body a boost. In skincare, a product can feature “pure vitamin C” front and center, lending the appearance that it’s bursting with a key ingredient when it’s merely fairy-dusted. Takeaway: Clinical research shows that Vitamin C requires a concentration of at least 5% to work.

L-ascorbic Acid or a Derivative?

Pure Vitamin C is also called ascorbic acid (or L-ascorbic acid) and is a highly active ingredient that brightens and tightens your skin. It’s also more unstable than the year 2020. L-ascorbic acid is easily the most fragile skincare essential, followed by retinol and green tea. It’s super sensitive to temperature, light, air, and the environment and can quickly oxidize and go rancid. Because of its finicky nature, formulators depend on other forms of vitamin C, aka derivatives. Takeaway: L-ascorbic acid is the only pure form of Vitamin C. 

Exponent Beauty Brightening Boost Vitamin C Serum

Features ultra-brightening 10% L-Ascorbic Acid—preserved in its most potent powder state—in every precise dose.

Not All Derivatives are Created Equal

If you want an alternative to L-ascorbic acid that won’t rapidly degrade, here are three best-in-class derivatives. However, you have been warned: these derivatives are less potent than pure L-ascorbic, ranging from a half to a sixth the equivalent concentration. So pay attention to total percentages on the label since to get to that 5% L-ascorbic benchmark, you’ll need at least double or more the derivative! 

Magnesium Ascorbyl Phosphate (MAP)

A stable, water soluble derivative of Vitamin C, it has the same potential to boost skin collagen synthesis as does Ascorbic Acid, but at lower concentrations. MAP may also be the preferred choice for those with sensitive skin or those wanting to avoid the exfoliating effects of highly acidic Ascorbic Acid. Note that 1% of MAP is equivalent to 0.58% L-Ascorbic so to hit that 5% magic concentration #, you’d need at least 10% MAP. Divide your MAP concentration by 2 to get to L-Ascorbic Acid. MAP is only half as potent as L-Ascorbic.

THD Ascorbate

A stable, oil-soluble form of Vitamin C, it can readily permeate cells and convert to pure Ascorbic Acid. Because of its extremely stable composition, it can be used on a daily basis without causing irritation. Note that 1% of THD is equivalent to 0.16% L-Ascorbic so to hit that 5% magic concentration #, you’d need at least 60% THD. Divide your THD concentration by 6 to get to L-Ascorbic Acid. THD is only one sixth as potent as L-Ascorbic.

Ascorbyl Glucoside

A water-soluble form of vitamin C that's combined with glucose, a sugar. Once absorbed into the skin, an enzyme called alpha-glucosidas breaks it down into L-ascorbic acid, delivering skin-brightening effects without irritation. Note that 1% of Ascorbyl Glucoside is equivalent to 0.52% L-Ascorbic so to hit that 5% magic concentration #, you’d need at least 10% Ascorbyl Glucoside. Divide your Ascorbyl Glucoside concentration by 2 to get to L-Ascorbic Acid. Ascorbyl Glucoside is only half as potent as L-Ascorbic. Takeaway: While these derivatives aren’t as potent as the pure stuff, they are stable alternatives. You need to have double or more the derivative concentration to hit an effective level.

How to Choose Effective Vitamin C Products

Our convenient roadmap for finding the bright stuff.

The Research: Comparison of Vitamin C Derivatives

We commissioned two primary research studies from October 2019 – February 2020 with CA-based Micro Quality Labs, the preeminent safety and ingredients testing facility for the Beauty & Personal Care industry. 

METHODOLOGY

4 flights of 5 bestselling products across price and retailer
Flights by active ingredient:
- Vitamin C
- Retinol (Vitamin A)
- CoQ10 (ubiquinone) 

 

PROTOCOL

• Products purchased at retail (just as a consumer would)
• Mimic consumer usage by opening, dispensing product every other day (exposing to oxygen, UV light)
• Samples taken and assayed to measure concentration of active ingredient on Day 1, Day 2, Week 2, Week 4
• Vitamin C products using derivative molecules were further tested for their pure Vitamin C (L-Ascorbic Acid) equivalency

DERIVATIVE VITAMIN C STUDY:

”Clean” beauty brands often use Vitamin C derivative ingredients rather than pure L-Ascorbic acid. These derivative molecules are marketed by ingredients suppliers as more stable than L-Ascorbic so ‘clean’ formulations can add fewer potentially harmful stabilizers and preservatives to their formulas but maintain some L-Ascorbic equivalency potency. The reality is that derivatives:

1. Are much more expensive
2. Still suffer from degradation (Tetrahexyldecycl Ascorbate loses 15% of concentration in 8 weeks)
3. Often have stabilizers added to them in the ingredient manufacturing process (i.e. the brand doesn’t have to list these ingredients)
4. Have very low equivalencies to L-Ascorbic so the actual benefit the consumer receives (% of L-Ascorbic) is very low

	Tetrahexyldecyl Ascorbate	3-O-Ethyl Ascorbic Acid	Ascorbyl Glucoside	Mg or Na Ascorbyl Phosphate	Ascorbyl Palmitate
L-Ascorbic Acid Equivalency	0.16	0.86	0.52	0.58	0.42

Results from our Independent Study at a Third Party Testing Lab

Vitamin C Derivatives	L-Ascorbic is X times more concentrated	1% of Derivative is Equivalent to what % L-Ascorbic?
Tetrahexyldecyl Ascorbate	6.4	0.16%
3-O-Ethyl Ascorbic Acid	1.2	0.86%
Ascorbyl Glucoside	2	0.52%
Mg or Na Ascorbyl Phosphate	2	0.58%
Ascorbyl Palmitate	2.4	0.42%

Cool chart but what does it all mean? If a product says it contains X% Vitamin C on the label or in marketing, check what’s on the ingredient list… divide by 2-6  and that’s what your L-Ascorbic value will be.