Tranexamic acid and vitamin C are two of the most talked-about brightening actives in skincare, and they’re often positioned as alternatives to each other. If you’ve been researching ingredients for uneven skin tone, you’ve almost certainly encountered both.

The truth is more interesting than that. Tranexamic acid vitamin C combinations, when used thoughtfully, complement each other rather than compete. They work through completely different mechanisms and suit different skin types.

Here’s what each one actually does, and how to decide which belongs in your ritual.

How Vitamin C Works on Skin

First, it inhibits an enzyme called tyrosinase, which is involved in the production of melanin. Less tyrosinase activity means less melanin produced, which over time reduces the appearance of dark spots and supports a more even complexion.

Second, it neutralises free radicals, the unstable molecules generated by UV exposure and pollution that contribute to oxidative stress, collagen breakdown, and dullness. This antioxidant action is one of the reasons vitamin C has such a strong reputation for making skin look more radiant.

The challenge with vitamin C is stability. L-ascorbic acid oxidises quickly when exposed to light and air, turning orange or brown and becoming less effective. Formulation matters enormously, and many vitamin C products on the market are past their useful life before they’re even opened. It can also cause irritation, particularly at higher concentrations, which makes it poorly suited to sensitive or reactive skin.

How Tranexamic Acid Works on Skin

Tranexamic acid takes a different route entirely.

Originally developed for medical use, it works by inhibiting plasmin, an enzyme that plays a role in triggering melanin production. Where vitamin C blocks melanin at the production stage via tyrosinase, tranexamic acid interrupts the chain of events that signals the skin to produce excess melanin in the first place. According to the British Association of Dermatologists (https://www.bad.org.uk/)

This makes it particularly effective for post-inflammatory hyperpigmentation, the dark marks left behind after breakouts or skin trauma, and for melasma, one of the most stubborn forms of uneven tone. Clinical studies using concentrations of 3 to 5% have consistently shown meaningful improvement in both conditions, often with fewer side effects than alternatives.

Crucially, tranexamic acid is also anti-inflammatory. It calms the skin as it works, which is why it’s so well suited to those whose skin has been sensitised by other treatments or who have reactive skin that doesn’t tolerate stronger actives.

Tranexamic Acid Vitamin C: The Key Differences

Both ingredients address hyperpigmentation, but they do it differently, suit different skin profiles, and have different practical considerations in a formula.

Stability. Tranexamic acid is inherently stable and doesn’t degrade in the way vitamin C does. A well-formulated tranexamic acid product holds its potency reliably. Vitamin C requires very careful formulation and storage to remain effective.

Tolerance. Tranexamic acid is gentler. It’s suitable for sensitive, reactive, and rosacea-prone skin. Vitamin C at higher concentrations can sting, cause temporary redness, or trigger flares in more sensitive skin types.

Mechanism. Vitamin C works via antioxidant action and tyrosinase inhibition. Tranexamic acid works earlier in the melanin production process, via plasmin inhibition. For stubborn hyperpigmentation, particularly melasma, tranexamic acid often shows stronger results.

Speed. Vitamin C can brighten skin relatively quickly through its antioxidant action. Tranexamic acid works more gradually, addressing the root cause rather than the surface. Results typically become visible after 8 to 12 weeks of consistent use.

Can You Use Both Together?

Yes, and for some skin types they work very well alongside each other. Vitamin C in the morning for its antioxidant and protective benefit, and tranexamic acid in the evening as part of a targeted treatment ritual, is a combination that makes good use of both.

That said, if your skin is sensitive, introducing one at a time and observing how it responds is always the more considered approach.

Which Is Right for Your Skin?

If your skin is reactive, sensitive, or prone to rosacea, tranexamic acid is very likely the better starting point. It’s effective, gentle, and doesn’t carry the instability or irritation risk that vitamin C can.

If you’re dealing with melasma specifically, the clinical evidence for tranexamic acid is particularly strong, and many dermatologists now consider it a first-line topical treatment for that condition.

If your primary concern is protecting skin from daily oxidative damage and maintaining general radiance rather than treating specific dark spots, vitamin C has a strong case, provided the formula is genuinely stable.

For most people looking to address uneven tone, dark spots, or post-breakout marks, tranexamic acid at 3% is where we’d point you first.

The Luna Selene Approach: The Best of Both

You don’t have to choose between tranexamic acid and vitamin C. With the right two products, your skin gets both.

Our Lunar Radiance Citrus Toning Elixir contains Orange Oil, a natural source of vitamin C, delivering the antioxidant and brightening benefits of vitamin C as the second step in your ritual. It preps the skin, adds radiance, and begins the brightening process before your serum even touches your face.

Then our Lacus Temporis Pro Collagen Boosting Serum takes over. With 3% Tranexamic Acid and 5% Niacinamide, it addresses hyperpigmentation at the source, gently and consistently, over time.

Used together, the two products cover both mechanisms: the antioxidant and surface-brightening action of vitamin C from the elixir, and the targeted melanin-interrupting action of tranexamic acid and niacinamide from the serum.

There’s one more thing they share. Both formulas contain our Toniq postbiotic, a Saccharomyces Barley Seed Ferment Filtrate upcycled from the gin industry. It supports the skin’s microbiome throughout both steps of the ritual, keeping the barrier calm and resilient as the actives do their work.

It’s a considered pairing. Two products, two brightening pathways, one unifying ingredient that keeps your skin steady throughout.

Both are 100% vegan, cruelty-free, and made in the UK.

If you’d like to understand more about what tranexamic acid does on its own, our post on what tranexamic acid does for skin covers it in more detail.