Do you need sunscreen if you use retinol or acids?

Yes, every morning, even if you only use them at night. The American Academy of Dermatology (AAD) says retinoids can make skin more sensitive to the sun, and advises using them only at night with sun protection during the day [1]. The FDA says AHAs raise sun sensitivity, and advises sun protection with BHAs too [2][3].

Why retinol raises sun sensitivity

The AAD’s advice for retinoids is night use only, plus daytime sun protection: shade, sun-protective clothing such as a wide-brimmed hat, and sunscreen [1]. A review of retinoids describes sun sensitivity as a side effect that normally shows up at the start of use [4].

Retinoid labels say the same thing.

• Tretinoin. The Retin-A Micro label advises daily sunscreen (SPF 15 or higher) and sun-protective clothing when UV exposure cannot be avoided. That includes days that are not sunny and days spent mostly inside [5].
• Adapalene. The Differin label says to limit sun exposure, including tanning beds, and to use sunscreen when going outdoors [6].

Why acids do too

The FDA reviewed studies on alpha hydroxy acids (AHAs) such as glycolic and lactic acid. After four weeks of AHA use, sensitivity to UV reddening rose by 18 percent [2]. Sensitivity to UV-induced cell damage doubled on average [2]. Within a week of stopping, sensitivity was back to normal [2].

That is why the FDA’s suggested AHA label says to use sunscreen, wear protective clothing and limit sun exposure while using the product and for a week afterward [2].

For beta hydroxy acids (BHAs), salicylic acid is the most common one in cosmetics [3]. The FDA’s advice is to use sun protection with any BHA product [3].

What to use and how much

The Retin-A Micro label sets a floor of SPF 15 [5]. The AAD’s general advice is SPF 30 or higher [7].

Amount matters. The AAD notes that many people apply only 20 to 50% of the sunscreen needed to get the SPF on the label [7].

Cloudy days, winter and indoors

The AAD says your skin is exposed to UV every time you go outside, even on cloudy days and in winter [8]. The Retin-A Micro label asks for daily protection even on days that are not sunny or when inside activities are expected [5]. The same label warns that weather extremes, such as severe wind or cold, may increase the risk of irritation [5].

If you get sunburned

Pause the strong products. The Retin-A Micro label says not to use it on sunburned skin until the sunburn is gone [5]. The AAD says never to exfoliate sunburned skin [9].

If you use a prescription retinoid such as tretinoin: Follow your prescriber’s instructions. Corneo schedules the rest.

What Corneo does

Corneo requires a morning sunscreen step in any routine with a retinoid, adapalene, an exfoliating acid or benzoyl peroxide. If your shelf has no sunscreen, that is the gap Corneo suggests filling first, and it puts sunscreen as the last morning step. Check retinol with sunscreen or audit your whole shelf.

FAQ

I only use retinol at night. Do I still need sunscreen?

Yes. The AAD pairs night-only retinoid use with sun protection during the day [1]. A review notes that sun sensitivity tends to appear early in retinoid use [4].

How long after stopping an AHA do I need extra sun care?

The FDA’s suggested AHA label says to keep using sun protection for a week after stopping [2]. In the FDA’s studies, sensitivity was back to normal within a week [2].

Is a moisturizer with SPF enough?

The AAD’s criteria are the same whatever the product: broad spectrum, SPF 30 or higher and water resistant [7]. Use at least 1 teaspoon on the face [8], and reapply outdoors about every two hours [7].