Retinoid Guide: What Are Retinol, Tretinoin and Adapalene, How Do You Start, and Who Should Not Use Them?

What is a retinoid?

Retinoid is the collective name for substances that are derived from vitamin A or act in a similar way to it. Retinoids applied to the skin increase the rate at which skin cells renew themselves and reduce clogging of the pores; for some there are also data suggesting that they support collagen production in the skin. For this reason they are used both in the treatment of acne and for skin changes due to sun damage.

This article deals only with retinoids applied to the skin. Isotretinoin taken by mouth is a separate medicine, very different in its effect and risks and used only under a physician's supervision; we touch on it briefly at the end of the article.

The retinoid family: retinol, retinaldehyde, adapalene, tretinoin, tazarotene

Not all retinoids are of the same strength. Some are found in cosmetic products, and some are medicines. Which substance is sold without a prescription and which on prescription varies from country to country; the table below gives a general framework.

Outside this list there are also newer prescription retinoids developed for acne. The percentage of retinol is not always stated on the label of cosmetic products; this makes it difficult to compare products with one another. You can ask your physician or pharmacist whether a product is a medicine or a cosmetic, on what terms it is sold in your country and whether it is suitable for you.

What is there evidence that retinoids help?

• Acne: the 2024 acne guideline of the American Academy of Dermatology lists topical retinoids among the treatments with a strong recommendation. Retinoids are often planned not on their own but together with other active substances; the guideline states that combining topical treatments with different mechanisms of action is good practice. Acne treatment is arranged by a physician.
• Sun damage and fine lines: according to a review of the subject, many retinoids have shown improvement in sun-damaged skin at both the clinical and the microscopic level; among them tretinoin is the most studied and probably the most potent. Most of the studies were carried out on sun-damaged skin.
• Retinol and retinaldehyde: they are reported to be less irritating; however, the evidence on them is more limited than for tretinoin.
• Appearance of pores, dark spots and new stretch marks: there are fewer data in these areas and the results are variable. The details are in our articles “Enlarged Pores” and “Stretch Marks (Striae)”.

Setting the right expectation is important. The effect of retinoids appears not within weeks but over months, and gradually. What can be expected is a moderate improvement in fine lines and skin texture; no cream removes deep lines, folds or sagging. For the different types of lines and the methods, see our article “Wrinkles”.

How do you start a retinoid?

The following are general principles. If you are using a prescription product, your physician's directions come first; if you are using a non-prescription product, the product's instructions for use come first.

• Ask first: dermatology sources advise you to ask a dermatologist whether a retinol-containing product is suitable for your skin before starting it. People with marked redness, dryness or a skin allergy may not be good candidates; redness can point to rosacea, and the treatment of that condition is different.
• Start slowly: dermatology sources recommend starting with a milder product at infrequent intervals (for example every other evening) and increasing the frequency as the skin gets used to it. Skipping this step can lead to irritation.
• Use it in the evening: because retinoids can make the skin sensitive to the sun, using them in the evening is recommended.
• Moisturise: using a moisturiser helps to reduce dryness and peeling.
• One new thing at a time: when starting a retinoid, do not add acid-containing products, exfoliating products and other ingredients that may irritate at the same time; ask your physician which can be used together.
• Take care with sensitive areas: the eye area, the sides of the nose and the corners of the mouth are irritated more easily.
• Be patient: it can take months to see a result; applying more, or more often, does not speed up the effect but increases irritation.

Retinoid irritation or allergy?

Many people who start a retinoid have redness, dryness, flaking, tightness and stinging in the first weeks. Reviews state that irritation reactions such as burning, flaking and inflammation of the skin are the main problem limiting the use of retinoids, and that this is more marked with tretinoin and tazarotene. This picture is usually not an allergy but irritation seen while the skin is adapting to the product, and it is expected to lessen as the routine is adjusted.

This distinction is not always easy; the table does not make a diagnosis. If the irritation does not ease within a few weeks, if it affects your daily life or if you are not sure, stop the product and consult your physician. In people with dark skin, irritation matters all the more because it can leave dark marks behind; dermatology sources recommend that irritation be watched closely in these people.

Retinoids and the sun

Retinoids can increase the skin's sensitivity to the sun. For this reason it is recommended that they be used in the evening and that during the day you protect yourself with shade, a hat, clothing and sunscreen. When sun protection is neglected, the benefit expected from a retinoid may be reduced; the sun is one of the main causes of fine lines and dark spots. For choosing a product, the amount and how often to reapply, see our article “Sunscreen Guide”.

Are retinoids used in pregnancy and breastfeeding?

Retinoids are not used in pregnancy or when planning a pregnancy. The American Academy of Dermatology states that retinoids should not be used in pregnancy; on its page on acne treatment it lists tazarotene among the medicines that should never be used in pregnancy, and for tretinoin and adapalene it reports that most experts recommend stopping treatment in pregnancy. The same caution applies to retinol in cosmetic products.

The reason for this caution is that retinoids taken by mouth are known to be capable of causing serious birth defects. With retinoids applied to the skin, the amount that passes into the body is much smaller. A 2026 systematic review and meta-analysis of women who had used topical retinoids in the first three months of pregnancy found no increase in the risk of birth defects or miscarriage; however, the authors note that the result rests predominantly on a single large registry study. These data are reassuring for people who have used a product without knowing they were pregnant; but they do not change the recommendation not to use them in pregnancy.

• If you are planning a pregnancy, tell your physician about your retinoid-containing products; your physician will determine when you should stop.
• If you learn that you are pregnant while using one, stop the product and tell the physician following your pregnancy. There is no need to panic, but it is important to let them know.
• If you are breastfeeding, consult your physician before starting or continuing a retinoid-containing product.

The details on skin care and procedures during this period are in our article “Medical Aesthetics in Pregnancy and Breastfeeding”.

Why are they paused before laser, peels, waxing and microneedling?

Retinoids speed up the renewal of the skin and can make its top layer more delicate; for this reason the skin may be more sensitive to some procedures. Dermatology sources recommend pausing products containing retinoids and glycolic acid for a while before laser treatments. It has been reported that when skin being treated with a prescription retinoid is waxed, the top layer of the skin can be stripped off together with the hair; for this reason a pause is also recommended before waxing.

With chemical peels and microneedling the position varies from physician to physician and with the procedure: before some peels a retinoid may be part of the preparation planned by the physician; in other cases you are asked to stop it. So do not decide on your own. The physician performing the procedure determines when you should pause and when you should start again afterwards.

• At the consultation before the procedure, mention all the retinoid-containing products you use, including non-prescription ones.
• If you are going to have facial waxing at a hairdresser's or beauty salon, say beforehand that you use a retinoid.
• Do not forget to ask when to restart the retinoid after the procedure.

For what to tell the physician before a procedure and general preparation, see our article “Preparing for a Medical Aesthetic Procedure”.

Oral isotretinoin is a separate matter

Isotretinoin is a retinoid taken by mouth, prescribed by a physician for acne that is severe or does not respond to other treatments. Because it can cause serious birth defects in pregnancy, it is used with strict pregnancy-prevention rules and regular monitoring. The information in this guide does not apply to isotretinoin.

Which aesthetic procedures can be carried out while taking isotretinoin or after it is a different question from that of topical retinoids; we deal with this subject in our article “Medical Aesthetics for People on Medication or with Chronic Conditions”. For the choice of procedures in people with ongoing acne, see our article “Medical Aesthetics for Active Acne”.