myru
Oily/Resilient
Another reason for the ineffectivity of the products, besides them containing a low percentage of ascorbic acid, could be that the vitamin c has already oxidized. Vitamin c is very unstable as an ingredient.
If you still want to give it a try, look for products that have at least 10% vitamin c and also contain tocopherol and ferulic acid. Those two ingredients help stabilize vitamin c. And remember to store your serum in the fridge to slow down the oxidization process. Since the percentage is going to be higher introduce it slowly into your routine, to see how your skin reacts.
Here are some recommendations

Maelove
The Glow Maker Antioxidant Serum
4.8
(26)
153

Paula's Choice
C15 Super Booster
4.4
(58)
316

Geek & Gorgeous
101 C-Glow 15% Vitamin C Serum
4.6
(61)
243

Timeless Skincare
10% Vitamin C + E Ferulic Acid Serum
3.7
(11)
34
11
0
Jhilik
Oily/Sensitive
thanks for the suggestions. I will try Paula's choice soon. this one is available in my country from the products you suggested
2
0
wyatt
Dry/Sensitive
these 3 have higher % of vitamin c which works great on my skin , but just one downfall it oxidises quite fast, so must refrigerate them

NEOGEN
Dermalogy Real Vita C Serum
4.2
(354)
256

COSRX
The Vitamin C23 Serum
4.5
(148)
174

NEOGEN
Dermalogy Real Vitamin C Serum
4.2
(19)
28
7
0
theskinilivein
Oily/Sensitive
Those products have a low percentage of vitamin C, which could at least partially explain the lack of results for you.
6
0



