Purito Vitamin C suddenly irritating during workouts

I currently use the Purito Pure Vitamin C serum, but I’ve noticed something odd…whenever I do heavy training sessions (around 2-2.5hours), the serum starts to irritate my skin a lot and causes redness.

Has anyone experienced something similar where vitamin C (especially L-ascorbic acid) becomes irritating under conditions like exercise, heat, or sweating?

🧴 Context about my skin:

Skin type: combination leaning normal

(slightly oily T-zone, normal to mildly dehydrated cheeks)

Sensitivity: mild redness on nose/cheeks, somewhat reactive barrier

💊 Current actives:

Tretinoin (Mytret 0.025%)

The Ordinary Multi-Peptide + Copper

Cos De BAHA – Azelaic Acid 10% Serum

I found some gentle alternatives if the problem is really the L-ascorbic acid, still have not decided which one to choose:

– Goodal Green Tangerine Vita-C serum

– BEAUTY OF JOSEON Light On Serum

– numbuzin No.5+ Glutathione Vitamin Concentrated Serum