Should I buy the highest percentage Vitamin C serum?

The short version….

In most cases, for a (topical application) to be biologically important (i.e., absorbed into your skin), it needs to have a Vitamin C (Ascorbic Acid) concentration MORE than Eight per cent.

Studies …show a concentration more than 20 percent does not increase its biological importance and, conversely, may cause some irritation.

Ravetti S et al, Ascorbic Acid in Skin Health. Cosmetics 2019, 6, 58; doi: 10.3390/cosmetics6040058

The long version: let’s talk about the science…

A long time ago in a galaxy we are in, Dr Pinell* (yup that guy (again)), and his colleagues conducted this experiment. They applied a range of 5% to 30% Vitamin C (L-Ascorbic Acid) solutions to pig skin (common practice) and their main findings were:

  • Even at 5 per cent, Ascorbic Acid accumulates in the skin (so even LOW amounts of Vitamin C are good news)
  • Ascorbic Acid levels in tissues INCREASED with concentration but plateaued at 20 per cent.
  • For concentrations greater than 20% levels of L-Ascorbic Acid started to drop.
  • Similar levels of L-Ascorbic Acid absorption occurs for both 10 per cent and 30 per cent.

Main takeaway: L-Ascorbic Acid concentrations above 20% are a waste.

Is there dissension in the ranks?

Yes. Some dermatologists and beauty brands violently disagree. The maximum concentration of powdered Ascorbic Acid I found was 100 per cent. The argument is that with a HIGHER concentration, simply more L-Ascorbic Acid is available to the skin.

What do I think?

Anything above 8% L-Ascorbic Acid is beneficial. Stick to an identifiable 15% – 20% L-Ascorbic Acid serum. Twenty plus L-Ascorbic Acid serums are a waste..

Are 20%+ Vitamin C serums common?

Unsurprisingly, 20%+ L-Ascorbic Acid products are uncommon, reflecting the fact that the rebellion is still in its infancy. If I were to a hazard a guess, scientists haven’t been able to refute the available clinical data that L-Ascorbic Acid uptake by the skin drastically starts to drop above 20%

That’s good news for us.

Products I would not buy because of the high Vitamin C content

Expensive Vit C serums
(L to R: Skin Design London C Antioxidant Glow – Vitamin C, The Inkey List Vitamin C Serum (30% Ascorbic Acid) DCL C Scape High Potency Night Booster 30 (GBP 108 for 30ml)
High Vit C products
(L to R: Vitamin C Suspension 30% in Silicone, 100% L-Ascorbic Asic Powder, Vitamin C Suspension 23% + HA Spheres 2%. All products by The Ordinary)

Are there any other Vitamin C serums you would not buy?

Yes. So many. But I really want to highlight this group of absolutely hideously expensive serums.

No one needs to buy such expensive products and I don’t care if you are a billionaire.

Vitamin C serums that are too expensive
(From L to R Zelens Power C (US$ 168), MZ Skin 10% Vitamin C Corrective Serum (US$ 390), Omorovicza Daily Vitamin C (US$ 150) and Amorepacific Youth Revolution Radiance Concentrator (US$ 250) (Prices are all for 30ml)

Closing

Thankfully, there are few products in the category of high percentage Vitamin C serums and I would be weary of buying such products, even if they are cheap. See also, The Gold Standard Vitamin C serums, Should I be using a topical Vitamin C serum?

That’s it from me. Drop me a line at email@happyskindays.com if you have any queries or comments.

* Dr Pinnell

Dr Pinnell is the co-inventor of the Duke Anti-oxidant patent and more information is available at this blog.

Source

Topical L-ascorbic acid: percutaneous absorption studies. Pinnell SR1Yang HOmar MMonteiro-Riviere NDeBuys HVWalker LCWang YLevine M.

***
Happy Skin Days ©  2021.  © Angeli Sinha 2021. All rights reserved. The contents of this blog, including images are protected by copyright law.  My content cannot be replicated without my consent. You can write to me at email@happyskindays.com

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