Niacinamide, Tranexamic Acid and Peptides: What the Actives Actually Do

An active is the ingredient in a formula that is doing a specific job, and everything else in the bottle exists to carry it, stabilize it and make it bearable to wear. Skincare actives explained honestly means describing what each one is understood to do inside skin, and stopping there.

This page covers three that appear on a lot of Korean cartons: niacinamide, tranexamic acid and peptides. It also covers the part the industry skips, which is that a stated concentration describes the bottle and not what reaches your skin.

Skincare actives explained: the short version

Active	What it is	Described mechanism	What it will not do
Niacinamide	A form of vitamin B3	Supports the skin's own lipid production, and interferes with pigment transfer between cells	Act as an exfoliant, or work on scars
Tranexamic acid	A synthetic amino acid analogue, originally a medicine	Interrupts a signaling pathway that tells pigment cells to switch on after UV exposure	Treat a medical pigmentation condition
Peptides	Short chains of amino acids	Act as messengers, depending on the sequence. Effects are sequence-specific	Behave like a retinoid, or like an injectable
Adenosine	A nucleoside found in all living cells	Used in Korea as a recognized wrinkle-claim ingredient at a set concentration	Carry that classification into the US market

Niacinamide, the one that does several jobs

Niacinamide is a form of vitamin B3. It is water-soluble, small, stable across a normal cosmetic pH range, and unusually easy to formulate with, which is why it turns up everywhere.

Inside skin it feeds into the coenzymes cells use for ordinary metabolism. Three effects come up consistently in the literature and in dermatology practice.

• Barrier support. Niacinamide is associated with the skin's own production of ceramides and other barrier lipids. That is why it appears in so many products aimed at skin barrier repair.
• Pigment transfer. It does not bleach anything and it does not block the enzyme that makes melanin. It is described as reducing the handover of finished pigment packages from pigment cells to surface cells.
• Sebum and visible redness. Both are commonly reported effects. Both vary widely between people, which is a polite way of saying you will not know until you try it.

Concentration, and the part nobody says out loud

Most cosmetic niacinamide sits somewhere between 2 and 10 percent. Products go much higher, including ours. The re:tones 01 pore ampoule is niacinamide at 210,000 ppm, which is 21 percent.

Higher is not automatically better. Past a point you are adding irritation risk rather than benefit, and niacinamide at high percentages stings some people, particularly on compromised skin. A number on a carton is a formulation fact, not a ranking.

The old warning about niacinamide and vitamin C is worth retiring. It came from lab conditions involving heat and unbuffered ingredients, where niacinamide can convert to nicotinic acid and cause flushing. Finished cosmetic formulas are not that experiment.

Tranexamic acid, borrowed from medicine

Tranexamic acid started as a drug. Taken systemically it reduces bleeding by slowing the breakdown of clots, and it has been used that way in medicine for decades.

The skin story came later, and from an observation rather than a plan. Patients taking it for other reasons were noticed to have changes in facial pigmentation, and topical versions followed.

The mechanism described in the literature runs through the same pathway. UV exposure activates plasmin in skin cells, and plasmin sits upstream of the signals that tell pigment cells to produce melanin. Tranexamic acid interferes with that activation, so the instruction to make pigment is quieter.

Two honest notes. Topical cosmetic use is a different thing from the oral prescription drug, which is not a skincare step and carries real medical considerations. And melasma is a medical condition: it belongs with a clinician, not with a shopping decision.

The re:tones 02 brightening ampoule uses tranexamic acid at 50,000 ppm, which is 5 percent, alongside niacinamide at 2 percent. Those are the formulation figures and nothing more. Uneven tone has several causes, and we cover them in how to fade dark spots.

Peptides, and why the category is confusing

A peptide is a short chain of amino acids. Proteins are long chains, and collagen is a protein, which is where most of the marketing confusion starts.

Applying collagen to skin does not add collagen to skin. The molecule is far too large to cross the outer layer, and the interesting peptides are not building blocks at all. They are messages.

The four groups

• Signal peptides. Fragments that resemble the pieces skin produces when its own matrix breaks down. The idea is that their presence reads as a prompt to build.
• Carrier peptides. Peptides that transport a trace mineral, copper being the usual one. The mineral is the point and the peptide is the vehicle.
• Enzyme-inhibiting peptides. Intended to slow the enzymes that break down structural proteins.
• Neurotransmitter-inhibiting peptides. The group acetyl hexapeptide-8 belongs to. In cell studies it interferes with the protein complex that releases signaling chemicals at a nerve ending.

What that means in practice

Acetyl hexapeptide-8 is often marketed with language borrowed from injectables. That comparison is a marketing move, not a technical claim. An injectable is delivered into muscle by a clinician. A cosmetic is applied to the surface of an intact barrier.

The real limitation for the whole peptide category is delivery. Peptides are water-loving and comparatively large, and the outer layer of skin is built to refuse exactly that kind of molecule. Much of the supporting evidence comes from cell and lab work, where the barrier is not part of the experiment.

That is not an argument against peptides. It is an argument for taking the delivery question seriously, which is the subject of why your serum is not absorbing.

The re:tones 03 wrinkle ampoule uses acetyl hexapeptide-8 at 500 ppm, which is 0.05 percent, with adenosine at 0.04 percent. Adenosine is the ingredient Korea's regulator recognizes for wrinkle claims at a defined concentration, and that classification is Korean. It does not transfer to a US label, and we do not present it as though it does.

The other names on the shelf

• Retinoids. Vitamin A derivatives. The best-evidenced topical category for visible ageing, and the most irritating. Cosmetic retinol and prescription tretinoin are not the same strength or the same regulatory object. Background in what causes wrinkles.
• Vitamin C. An antioxidant. Pure L-ascorbic acid needs a low pH and oxidises easily, which is why formulas turn orange. Derivatives are more stable and behave differently.
• AHAs and BHAs. Exfoliating acids. Glycolic and lactic work on the surface, salicylic is oil-soluble and gets into pores. Easy to overdo, and the most common cause of a broken barrier.
• Azelaic acid. Used for tone and for visible redness, and generally tolerated well. Higher strengths are prescription in the US.
• Hyaluronic acid. A humectant, not an active in the treatment sense. It holds water in the upper layers. In dry air it needs something occlusive above it.
• Centella, panthenol, allantoin. Soothing agents. Sensible in a barrier formula. Not doing structural work.

How to read a concentration without being fooled

1. Percentages only compare within the same ingredient. Five percent of one thing and five percent of another have no relationship at all.
2. ppm and percent are the same scale. 10,000 ppm is 1 percent. Brands choose whichever number looks larger, and we do it too.
3. The vehicle decides a lot. pH, solvent and texture change how an ingredient behaves more than a few extra points of concentration.
4. Irritation scales faster than benefit. Every active has a level past which you are buying discomfort.
5. None of it matters if nothing gets in. This is the number no carton prints.

How long before you can judge an active

Skin works on its own schedule, and that schedule is slower than a product review cycle. Surface cells take several weeks to work their way up and shed, so almost nothing visible happens faster than that.

Rough guidance, offered as expectation-setting rather than a promise. Comfort and surface feel can change within days. Anything involving pigment moves in months, since you are waiting on cells that were already loaded before you started. Anything involving skin structure is slower still.

Two practical consequences. First, judging a product after a week tells you about tolerance, not about anything else. Second, the sting or flaking that shows up early is information worth acting on immediately, while the absence of a visible change is not.

Give a new active eight to twelve weeks of consistent use before deciding. Keep everything else in the routine steady across that period, or you will not know what did what.

The delivery problem, stated plainly

The outer layer of your skin is a barrier, and its job is to keep things out. It does not evaluate your ingredient list. Most of what you apply stays on top, dries, and ends up on your pillowcase.

That is why re:tones sells both halves. The MTS device opens temporary channels through that layer, and the ampoule is released at the moment the needle meets skin. The formula and the route in arrive together, which is a mechanism rather than a promise about your face. It is set out in full on the science page.

It also explains the format. You are applying to a temporarily open barrier, so the ampoule is crimp-sealed medical glass that you open yourself, rather than a pump that meets air and fingertips daily.

If you want the shortest route to one ampoule instead of three, the ampoule finder matches a concern to a position on the dial. Sequencing matters too, and that is covered in the skincare layering order reference. For why so many of these numbers appear on Korean packaging in the first place, see K-beauty, explained.

Frequently asked questions

Can I use niacinamide and tranexamic acid together?

Yes. They are frequently formulated together, and our 02 ampoule contains both. They work through different mechanisms, so there is no conflict to manage. Introduce them as one product, not two, so you can tell what your skin is reacting to.

Is 21 percent niacinamide better than 5 percent?

Not automatically. Above a certain level you are adding irritation risk rather than benefit, and high percentages sting some people. If your barrier is compromised, start lower or repair first and come back to it.

Do peptides really work in a cream?

The mechanisms are real in the laboratory. The open question is delivery, since peptides are water-loving and relatively large, and the outer layer of skin is built to stop molecules like that. Treat confident promises about peptide creams with suspicion.

How many actives can I use at once?

One new one at a time, held for at least two weeks. Beyond two or three actives in a routine you lose the ability to tell which product is helping and which is causing a reaction.

Which active should I start with?

Sunscreen, which is not glamorous and is the only one with an obvious case for everybody. After that, choose the active that matches a concern you can actually name. If you cannot name one, you do not need one yet.

Are these ampoules a treatment for melasma or acne?

No. They are cosmetics, not medicines, and they are not intended to diagnose or treat any condition. Melasma, acne and persistent pigmentation are medical matters and belong with a dermatologist.