The Top 8 ingredients to look for in Skin Serums

A client once brought me a serum she had bought from a luxury boutique. Beautiful bottle. Beautiful story. Beautiful price.

But she wasn’t seeing results.

She asked me, “Is this even doing anything?”

I turned the bottle around. Beyond “botanical complexes” and “proprietary blends,” there was very little to read. No clear active strategy. No real concentration cues. No vitamin C. No retinoid. No peptides. No barrier-supporting ingredients in any meaningful way.

It was not a bad product. It was simply not doing what she thought she had paid for.

Then I showed her a $30 serum from the pharmacy shelf: niacinamide, zinc, hyaluronic acid. Simple, transparent, well understood.

I told her: don’t pay for mystery. Pay for ingredients you can understand.

Six weeks later, her skin looked calmer, smoother, more balanced. Not because the product was expensive. Because the formula made sense.

That is the first lesson of good skincare: ingredients matter.
But the second lesson is even more important: formulation is what makes them work beautifully.

A good serum should not be chosen because it is trending, expensive, or beautifully packaged. It should be chosen because its active ingredients match your skin’s needs — and because the formula is stable, well balanced, and something your skin can actually tolerate consistently.

Below are the eight ingredients worth knowing, why they matter, and how to read a serum label like a pharmacist.

---

The eight ingredients to look for

1. Retinoids

Retinol, retinaldehyde, retinyl esters

Retinoids are among the most studied ingredients in skincare. They help support skin renewal, improve the look of fine lines, soften uneven texture, and visibly refine the skin over time.

But more is not always better.

A high concentration can be powerful, but it can also be irritating — especially for sensitive or compromised skin. The right retinoid is the one your skin can tolerate consistently.

Look for retinol or retinaldehyde in the first half of the ingredient list, and use it at night. Always pair with daily SPF.

For the full timeline of when results can appear, see our guide on how long retinol takes to work.

---

2. Vitamin C

L-ascorbic acid, tetrahexyldecyl ascorbate, and other stable forms

Vitamin C is a brightening antioxidant. It helps protect the skin from environmental stressors, supports a more even-looking tone, and helps improve the appearance of dullness.

The important word here is stable.

L-ascorbic acid is the most studied form, but it can degrade quickly when exposed to air and light. More stable forms, like tetrahexyldecyl ascorbate, can be easier to formulate and more comfortable for some skin types.

Look for opaque, airtight packaging. With vitamin C, the bottle matters almost as much as the ingredient.

---

3. Hyaluronic Acid

Hyaluronic acid is a humectant, which means it attracts and holds water. It helps the skin look plumper, softer, and more hydrated.

But hyaluronic acid alone is not always enough.

For dry or barrier-impaired skin, it works best when paired with ingredients that help seal hydration in — such as lipids, butters, waxes, or other barrier-supporting ingredients.

Hydration is not just about adding water. It is about helping the skin keep it.

---

4. Niacinamide

Vitamin B3

Niacinamide is one of the most useful and well-tolerated ingredients in modern skincare.

It helps support the skin barrier, visibly reduce redness, refine the look of pores, and improve uneven tone. It is often a good option for sensitive skin, especially when retinoids or acids feel too aggressive.

It is not the flashiest ingredient. But in a well-formulated product, it is one of the most reliable.

---

5. Peptides

Palmitoyl pentapeptide-4, acetyl hexapeptide-8, and others

Peptides are amino acid chains that help support the skin’s visible firmness and elasticity.

Different peptides have different roles. Some are used to support the look of firmness. Others help soften the appearance of expression lines. Others work best in combination with barrier-repair ingredients.

The key is not simply seeing “peptides” on a label. The key is understanding what they are paired with — because peptides perform best inside a thoughtful formula, not as decoration on an ingredient list.

---

6. Antioxidants

Vitamin E, ferulic acid, green tea extract

Antioxidants help protect the skin from visible damage caused by environmental stressors like pollution, UV exposure, and oxidative stress.

They often work beautifully in pairs.

Vitamin C and vitamin E, for example, are a classic combination. Ferulic acid can help support antioxidant stability. Green tea extract can bring a calming, protective quality to the formula.

One antioxidant is good. A well-designed antioxidant system is better.

---

7. Humectants beyond hyaluronic acid

Glycerin, propanediol

Glycerin is one of the most underrated ingredients in skincare.

It draws water into the skin, supports hydration, and is often extremely well tolerated. It is also inexpensive enough to be used generously, which is why it appears in some of the best formulas in the pharmacy.

Look for glycerin in the first five ingredients. When it is high on the list, it usually means the formula was designed with hydration in mind.

---

8. AHAs and BHAs

Lactic acid, glycolic acid, salicylic acid

Exfoliating acids help remove dead surface cells so the skin can look smoother, brighter, and more even.

AHAs, such as lactic and glycolic acid, work mostly on the surface. BHAs, such as salicylic acid, are oil-soluble and can be useful for congested pores.

But exfoliation should never feel like punishment.

If your skin is sensitive, start slowly. Do not pair exfoliating acids with retinoids on the same night. And if your barrier feels tight, burning, or reactive, pause.

A healthy glow starts with a healthy barrier.

---

Considerations beyond ingredients

The label tells you what is inside the bottle.
It does not tell you whether that bottle is right for your skin.

Before choosing a serum, consider these five things.

Your skin type

Oily skin often prefers lighter, water-based textures. Dry skin usually needs richer, more nourishing formulas. Sensitive skin needs fewer irritants and a slower introduction to active ingredients.

Your skin barrier matters more than your skin “category.”

Your specific concern

Fine lines? Look for retinoids and peptides.
Dullness? Vitamin C or gentle exfoliation.
Dehydration? Hyaluronic acid, glycerin, and barrier-supporting ingredients.
Redness or sensitivity? Niacinamide and calming actives.

The best serum is not the one with the most ingredients. It is the one with the right ingredients for your skin.

Concentration

A higher percentage can sound impressive. But higher does not always mean better.

The skin needs consistency more than intensity. A lower concentration used regularly and comfortably often gives better visible results than a strong product you can only tolerate once a week.

Formula stability

Some ingredients are fragile. Vitamin C, retinoids, and certain antioxidants can degrade when exposed to light, air, or heat.

Look for protective packaging: opaque, airtight, and well-designed. Clear bottles and open droppers are not always ideal for unstable actives.

Real testing

Look for clinical testing, dermatologist evaluation, ingredient transparency, and published results.

Adjectives are easy. Numbers are harder.
A serious formula should be able to show more than beautiful words.

---

How some popular serums compare

A side-by-side of serums on the market that meet different ingredient needs. Bonjout Le Balm is included as our own formula — judge accordingly. The other entries are independent options worth considering depending on your skin type, concern, and routine.

---

If you are choosing between options

The question is not: “Which serum is best?”

The better question is: “Which formula is right for my skin, my barrier, and my routine?”

A hyaluronic acid serum may be perfect for dehydration but not enough for visible signs of aging. A retinoid may be powerful but too irritating for a compromised barrier. A vitamin C serum may brighten beautifully, but only if it is stable and well formulated.

This is why Bonjout does not believe in chasing one active after another.

We believe in formulation: the art of bringing the right ingredients together, at the right concentration, in a texture your skin wants to use every day.

That is where performance becomes pleasure.
And where consistency becomes results.

---

The Bonjout take

The serum aisle is loud.

Brands compete on packaging, price, trends, and promises. But a pharmacist looks somewhere else first: the ingredient list.

Look for actives you recognize. Look for stable forms. Look for protective packaging. Look for formulas that support the skin barrier instead of overwhelming it. And look for brands that publish real testing, not just adjectives.

The best serum is not always the most expensive, the most viral, or the most complicated.

It is the one that respects your skin, supports its barrier, and brings together the right ingredients with intention.

That is the French pharmacy way.

Less noise. Better formulas.