Retinol: what it is, what it does and how to use it

In this article

1What is retinol? 2What does retinol do for your skin? 3What concentration is effective? 4Which skin types benefit most? 5How to start using retinol 6What to combine it with 7Retinol and pregnancy 8The 5 most common mistakes 9How long until you see results? 10Frequently asked questions

What is retinol?

Retinol is a form of vitamin A that your skin can use directly. It belongs to the retinoid family, a group of vitamin A derivatives that also includes retinal (retinaldehyde) and retinoic acid (tretinoin, the latter available only by prescription).

How retinol works in your skin

When you apply retinol to your skin, cutaneous enzymes convert it first into retinaldehyde and then into retinoic acid, the active form capable of modifying cellular behaviour. This two-step conversion process is precisely what makes cosmetic retinol more tolerable than prescription tretinoin: it loses some potency along the way, but gains significantly in tolerability. For most skin types, that balance is an advantage, not a drawback.

An active ingredient with over 30 years of evidence

Research on retinoids dates back to the 1970s, when they were first used in dermatology to treat acne and photoageing. Retinol in cosmetic format arrived in the 1990s and has since accumulated a scientific track record that few actives can match: over 700 published studies confirm its efficacy for treating wrinkles, dark spots, loss of firmness and uneven texture.

The fact that an active ingredient has been on the market for over three decades and is still considered the gold standard in anti-ageing says a great deal. This is not a passing trend or a marketing ingredient — it is an active whose efficacy has been validated time and again under controlled conditions.

What does retinol do for your skin?

Retinol is a true all-rounder. It doesn't do just one thing well — it acts simultaneously on several biological pathways in the skin, making it one of the most versatile ingredients in cosmetics. These are its main functions, all backed by scientific research:

Reduces wrinkles and fine lines

It stimulates the synthesis of type I and III collagen in the dermis and accelerates epidermal cell renewal. The visible result is a reduction in the depth of fine lines and an improvement in overall facial firmness.

Evens out skin tone and reduces dark spots

It inhibits tyrosinase activity, the enzyme responsible for melanin production, and disperses melanin already accumulated in the epidermis. This translates into a visible reduction of sun spots, melasma and uneven tone.

Renews skin texture

It promotes the turnover of corneocytes (the dead cells on the outermost layer), giving way to smoother skin with less visible pores and a more radiant appearance. This is what some people describe as the retinol "glow effect".

Protects against photoageing

Its antioxidant effect helps neutralise some of the damage accumulated from ultraviolet radiation. Remember: retinol is used at night to repair, and sunscreen in the morning to prevent. They are two complementary steps in your routine that work at different times of the day.

When will you see the first results?

It's essential to understand that retinol does not deliver immediate results. The skin's cell renewal cycle lasts between 28 and 45 days (and slows down with age), so the first visible improvements take a minimum of 4 weeks. Truly significant results — measurable wrinkle reduction, clear improvement in dark spots — are observed from 3 months of consistent use onwards. Patience and consistency are part of the treatment.

What concentration of retinol is effective?

Not everything labelled "retinol" works the same way. Concentration makes an enormous difference, and the reality is that many products on the market contain amounts so low that the effect is more placebo than real. Here's what the evidence says about the ranges that work:

0.01% – 0.1% (beginner level)

Concentration for very sensitive skin or first contact with the active. Efficacy is limited, but tolerance is very good. Useful as an adaptation phase during the first 2–4 weeks.

0.1% – 0.3% (standard level)

The range with the best balance between efficacy and tolerance. It is the most studied concentration in clinical trials and delivers consistent results with a manageable irritation profile. If you don't know where to start, this is where you should be.

0.3% – 0.5% (advanced level)

For skin that has been using retinol for weeks or months without issues. It offers greater anti-wrinkle and brightening efficacy, but the risk of irritation in the first weeks is higher. It requires your skin to already be "retinised".

0.5% – 1% (intensive level)

Only for skin with proven tolerance and, preferably, with dermatological supervision. These percentages are found in professional-grade products.

Concentration isn't everything

The golden rule of retinol is to start low and work your way up. A well-formulated 0.3% — with a gradual release system and soothing actives like niacinamide or panthenol — can deliver better results than a 1% that irritates you and you end up abandoning after a month. The best retinol concentration is the one you use consistently.

Moreover, it's not just about concentration: the formulation determines the stability and real efficacy of retinol. An encapsulated or liposomal retinol can be more effective and better tolerated than a free retinol at a higher percentage. Look not only at the "how much" but at the "how" it's formulated.

Which skin types benefit most from retinol?

Retinol can be used on almost all skin types, but its benefit is not the same for everyone:

Mature skin (35+)

This is where retinol shines brightest. Collagen production begins to decline significantly from age 30, and retinol is one of the few cosmetic actives that can stimulate it. If you have fine lines, loss of firmness or accumulated sun spots, retinol should be a pillar of your night-time routine.

Normal to combination skin

Tolerates retinol well from standard concentrations (0.1–0.3%). This is the skin type where the gradual introduction protocol works most predictably.

Oily, acne-prone skin

Retinol has keratolytic properties that help unclog pores and regulate the cell cycle. It is compatible with acne-prone skin, but be careful not to combine it with other aggressive actives (salicylic acid, benzoyl peroxide) on the same night.

Sensitive skin

It can use retinol, but with greater caution: start with concentrations of 0.05–0.1%, apply a thin layer of moisturiser before the retinol (the "sandwich" technique), and accept that it may never reach daily use. In these cases, it's worth looking for liposomal formulations or those with more stable release systems, which improve tolerance without sacrificing efficacy. And if tolerance still cannot be achieved, bakuchiol is a real alternative that can offer very similar results with a much lower irritation profile.

Dry skin

Retinol can accentuate initial dryness, so it is essential to accompany it with a good moisturiser containing ceramides or hyaluronic acid. Dryness usually subsides after the first 3–4 weeks of use.

How to start using retinol without irritating your skin

The most common mistake with retinol is jumping straight into using it every night from day one. Your skin needs an adaptation period that dermatologists call "retinisation" — and skipping it is the fastest way to end up with a red, flaking face and a product abandoned in a drawer.

Here's the protocol that works:

Weeks 1–2: two nights per week

Apply a minimal amount (pea-sized for the entire face) on completely dry skin. This detail is crucial: damp skin increases absorption and with it, irritation. Wait at least 20 minutes after washing your face. Apply moisturiser on top, 5 minutes later.

Weeks 3–4: three nights per week

If there is no significant irritation, increase the frequency. If you notice redness, tightness or flaking, maintain two nights per week for two more weeks. There's no rush.

Month 2: alternate nights

The skin begins to develop real tolerance. Always apply moisturiser on top. If you reach this point without problems, retinol is now integrated into your routine.

Month 3 onwards: every night (if your skin allows it)

Some skin types never reach daily use, and that's perfectly fine. Alternate nights may be your ideal long-term dose. Don't force yourself to reach daily use if your skin doesn't need it.

Sunscreen is not optional

A detail that many articles don't mention: throughout this entire process, SPF 50 sunscreen every morning is mandatory. No exceptions, even on cloudy days. Not because retinol is photosensitising per se, but because renewed skin is more vulnerable to ultraviolet radiation.

What actives to combine retinol with

Not all actives are good companions for retinol. Some enhance its effects synergistically, others cancel them out due to chemical incompatibility, and others can be combinations that are too aggressive for your skin.

Pairs well with

Hyaluronic acid. Provides the hydration that retinol can compromise. Apply it before or after retinol, or use a retinol that already includes it in its formulation.

Niacinamide (vitamin B3). Calms irritation, strengthens the skin barrier and enhances the anti-wrinkle effect. It is probably retinol's best companion.

Peptides. Anti-ageing reinforcement through a complementary pathway (collagen stimulation via peptide signalling, different from retinol's mechanism).

Ceramides. Repair the skin barrier, which retinol can compromise during the first weeks.

Avoid combining (at the same time of application)

Vitamin C in ascorbic acid form. They work at different pH levels and can cancel each other out. The solution is simple: vitamin C in the morning, retinol at night.

AHAs and BHAs (glycolic acid, salicylic acid, etc.). Combining retinol with an exfoliating acid on the same night amounts to a double assault on the skin barrier. Alternate nights: retinol one night, exfoliant the next.

Benzoyl peroxide. Degrades the retinol molecule through oxidation, reducing it to an inactive form. If you use both for acne, apply them at different times of the day.

Retinol and pregnancy: what you need to know

This point admits no nuance: retinol and all retinoids are contraindicated during pregnancy and breastfeeding.

The evidence of teratogenic risk (harm to the foetus) with oral retinoids such as isotretinoin is solid. With topical retinoids like cosmetic retinol, systemic absorption is much lower and the theoretical risk is low, but pharmacological prudence dictates that no retinoid should be used during pregnancy or breastfeeding. This is not an exaggerated precaution — it is the medical standard.

If you are pregnant, planning a pregnancy or breastfeeding, discontinue retinol and replace it with bakuchiol. It is the plant-based alternative with proven anti-ageing efficacy in direct comparative studies against retinol, with a safety profile compatible with pregnancy and breastfeeding.

The 5 most common mistakes when using retinol

Retinol is a potent active, but if used incorrectly it won't deliver the results you're hoping for. These are the mistakes we see most frequently:

1. Starting with daily use

Initial enthusiasm leads many people to apply retinol every night from the very first moment. The usual result is irritation, redness and product abandonment. Start with 2 nights per week and increase gradually.

2. Applying on damp skin

Residual moisture after washing your face acts as a penetration enhancer. More penetration = more irritation. Always wait until your skin is completely dry before applying retinol.

3. Forgetting sunscreen

Skin renewed by retinol is more sensitive to UV radiation. Not using SPF 50 the day after using retinol is like sanding a wall and not applying primer: the damage multiplies.

4. Giving up at the first sign of flaking

Mild flaking during the first 2–3 weeks is normal and has its own name: retinisation. It's a sign that the skin is renewing faster than usual. If flaking is severe, painful or cracked, stop and consult a professional.

5. Mixing with exfoliating acids on the same night

Retinol + glycolic or salicylic acid on the same night is one of the most damaging combinations for the skin barrier. Alternate nights, don't layer them.

How long does retinol take to work?

Retinol is not an instant-results active. If someone promises you visible changes in a week, be sceptical.

Weeks 1–3: adaptation

Adaptation period. Possible dryness, tightness or mild flaking. These are not side effects — it's retinisation. The skin is adapting to the accelerated renewal rate.

Weeks 4–8: first visible results

Improvement in skin radiance and texture. Pores begin to look less dilated. This is when most people notice the "glow effect".

Months 3–6: significant results

Measurable reduction of fine wrinkles, improvement in dark spots, greater firmness. This is when retinol shows its true capability.

Beyond 6 months: cumulative results

Retinol continues to improve skin quality with continued use. There is no short-term efficacy ceiling — the longer you use it (correctly), the better the results.

Consistency is as important as concentration. A 0.3% retinol used consistently for 6 months will deliver better results than a 1% used irregularly over the same period.

Frequently asked questions about retinol

Sources and references

1. Mukherjee S, et al. "Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety." Clinical Interventions in Aging, 2006;1(4):327-348. [DOI 1]

2. Zasada M, Budzisz E. "Retinoids: active molecules influencing skin structure formation in cosmetic and dermatological treatments." Postepy Dermatologii i Alergologii, 2019;36(4):392-397. [DOI 2]

3. Kong R, et al. "A comparative study of the effects of retinol and retinoic acid on histological, molecular, and clinical properties of human skin." Journal of Cosmetic Dermatology, 2016;15(1):49-57. [DOI 3]