Editor’s note: We searched the SkinGuide catalog for drugstore vitamin C serums under $20 targeted to dark spots and dullness. At the time of publication, no qualifying products were available to link directly from our database. We’ll update this page as soon as new budget-friendly options are added.

In the meantime, here’s how to shop smart on a tight budget:

• Look for stabilized vitamin C forms like sodium ascorbyl phosphate, ascorbyl glucoside, or 3‑O‑ethyl ascorbic acid (they’re often gentler and more affordable).
• Pair vitamin C with niacinamide for tone-evening and SPF every morning to prevent new dark spots.
• Opaque or amber packaging helps protect vitamin C from light and air—vital for potency.
• Start 3–4 mornings per week, then build to daily as tolerated.

Not sure which formula will love your skin back? Take the quick Skin Type Test to personalize your brightening routine: skinguide.beauty.

Bookmark this roundup—we’ll drop our editor-tested under‑$20 drugstore buys with live links as soon as they’re in stock.