Anua Niacinamide 10% + TXA 4% Dark Spot Serum 1 fl oz

What it is

The Anua Niacinamide 10% + TXA 4% Dark Spot Serum is a lightweight, water-based brightening serum that pairs two well-studied depigmenting actives — niacinamide and tranexamic acid — with hyaluronic acid to target post-inflammatory marks, sun spots, and uneven tone. At a 10% niacinamide concentration, it sits at the higher end of what over-the-counter formulas typically deliver, while the 4% tranexamic acid (TXA) works through a complementary mechanism to niacinamide, addressing melanin overproduction from a different pathway. The result is a dual-action formula designed to visibly fade existing discoloration while helping to slow the formation of new dark spots over time.

Who it's for

This serum is a strong fit for anyone dealing with post-acne marks, sun-induced hyperpigmentation, or an overall dull, uneven complexion. Because niacinamide also regulates sebum production and can minimize the look of enlarged pores, people with oily or combination skin tend to find it particularly compatible. It layers well under moisturizer without feeling heavy, which makes it suitable for those who prefer a streamlined routine.

People with very dry or sensitized skin should proceed with some caution: high-dose niacinamide can cause transient flushing or tingling in a small subset of users, though this is relatively uncommon at the concentrations used here. Those actively using prescription-strength retinoids or exfoliating acids should introduce this gradually and monitor for irritation. If you have a known sensitivity to niacinamide, this formula is best avoided entirely.

How to use it

Apply in the serum step of your AM or PM routine, after cleansing and any water-based toning step, but before moisturizer and — in the morning — before SPF. Dispense two to three drops and press gently into the face and neck, focusing on areas of concern such as cheeks, forehead, or the upper lip. Start with once daily to gauge your skin's response, then work up to twice daily if tolerated.

Consistency is key with brightening actives. Most users begin to notice a visible difference in tone evenness after four to eight weeks of regular use. Because niacinamide and TXA work on melanin synthesis and transfer rather than physically exfoliating pigment away, the process is gradual — but the payoff tends to be durable. Always follow with a broad-spectrum SPF 30 or higher in the morning; UV exposure is one of the primary drivers of hyperpigmentation and will work against any brightening serum you're using.

Key ingredients

Niacinamide (10%): A form of vitamin B3 that has been shown to inhibit the transfer of melanosomes — the pigment-carrying structures — from melanocyte cells to surrounding skin cells. At 10%, it also helps to visibly tighten the look of pores and regulate oil production, making it one of the most versatile actives in a brightening formula. It additionally supports the skin's barrier function, which helps keep skin resilient during treatment.

Tranexamic Acid (4%): TXA blocks plasminogen activators in keratinocytes, reducing the downstream signals that trigger excess melanin synthesis — a mechanism distinct from niacinamide's. This complementary action is why the two actives are frequently paired: together they address the hyperpigmentation pathway at more than one point. TXA is generally considered well-tolerated and is less likely to cause irritation than some other brightening agents such as kojic acid or high-dose vitamin C.

Hyaluronic Acid: A humectant that draws moisture from the environment and deeper skin layers to the surface, helping to keep the complexion hydrated and plump throughout treatment. It also helps offset any dryness that occasionally accompanies high-concentration active serums.

Pros & cons

• Dual active approach — niacinamide and TXA target hyperpigmentation through distinct mechanisms
• High 10% niacinamide concentration for a meaningful brightening and pore-refining effect
• Hyaluronic acid adds hydration without heaviness
• Lightweight, water-based texture layers cleanly under other products
• Well-reviewed by a large number of shoppers (4.5 out of 5 across more than 15,000 ratings)
• Addresses multiple concerns — dark spots, dullness, oiliness — in a single step

• Results require four to eight weeks of consistent use; not a fast-acting fix
• High niacinamide doses occasionally cause temporary flushing or tingling in sensitive skin
• 1 fl oz bottle may run out quickly for those applying twice daily to the face and neck
• Does not contain vitamin C, retinol, or AHAs, so it may need to be complemented if those actives are a priority

How it compares

If your hyperpigmentation is primarily driven by sun exposure rather than post-acne marks, a vitamin C-based approach can be effective alongside or instead of a niacinamide serum. TruSkin Vitamin C Serum with Hyaluronic Acid & Vitamin E combines ascorbic acid with vitamin E and ferulic acid, a classic antioxidant stack that targets oxidative pigmentation and brightens by a different mechanism than niacinamide or TXA. Shoppers who want more dedicated hydration support rather than active brightening may find Tree of Life Hyaluronic Acid Serum for Face a more appropriate standalone hydration layer, freeing up a brightening serum slot for a more targeted formula like this one.

The verdict

The Anua Niacinamide 10% + TXA 4% Dark Spot Serum earns its strong ratings by combining two actives that genuinely work, at concentrations meaningful enough to make a difference over time. It is not a quick fix, and it will not replace SPF — nothing does. But for shoppers committed to a consistent skincare routine who want to address post-acne marks, uneven tone, or visible pores with a well-formulated, low-irritation serum, this is a credible and practical choice. The inclusion of hyaluronic acid keeps the experience comfortable, and the 10% niacinamide load means oily skin types get meaningful pore and sebum benefits alongside the brightening action.