Name: Custom Formula (Tretinoin 0.009%, Clindamycin 1%, Azelaic Acid 9%)
Brand: Curology

What's inside

Ingredients Explained

Tretinoin

Skin Conditioning

Tretinoin (aka retinoic acid) is the gold standard retinoid in dermatology because it's the form of vitamin A that your skin can use right away. It's a prescription drug and regulated as medication in most countries.

Unlike retinol, it skips the conversion steps and goes straight to work.

Inside your skin cells, it binds to receptors called retinoic acid receptors and switches on the genes that control how skin cells behave.

For acne, it helps your skin shed dead cells properly instead of letting them build up and clog your pores (this is what turns into blackheads and pimples). It also calms redness/swelling, which is why it's a FDA-approved acne treatment.

Tretinoin also tells your skin to make more collagen and slows down the stuff that breaks collagen apart too. Over time, your skin looks smoother, softer, and more even, with fewer lines lines and sun spots.

The evidence for this ingredient is strong:

A systematic review of randomized controlled trials found that topical tretinoin consistently improved wrinkles, pigmentation, sallowness, and dark spots. Results typically showed up as early as one month and lasted out to 24 months.

All studies also found this ingredient to be safe and well-tolerated.

Typical concentrations run from about 0.01-0.1%, with 0.025%-0.1% being the usual range studied for photoaging and a 0.05% cream producing measurable wrinkle/roughness improvements in large six-month trials.

The main trade-off is irritation; dryness, peeling, redness, and sun sensitivity are common in the first few weeks so be sure to pair it well with a good moisturizer and daily sunscreen.

Learn about a form of retinoid you can purchase at the store, retinol.

Learn more about Tretinoin

Clindamycin

Clindamycin is a prescription lincosamide antibiotic used in topical acne treatments to kill acne-causing bacteria (C. acnes) and reduce inflammation.

It's generally found in prescription products rather than standard over-the-counter cosmetics.

Azelaic Acid

Buffering, Masking

Azelaic acid is a multitasker ingredient that helps treat acne, pigmentation, and irritation. It is a great option for sensitive skin.

What makes it special?

OTC Azelaic acid is usually available in concentrations from 10-15% and anything over requires a prescription.

Here's what each tier does best:

Unlike other acids, azelaic acid will not make your skin more photosensitive/sun sensitive.

Though this ingredient is naturally occurring in grains like wheat, rye, and barley, it is usually synthetically created for cosmetics to ensure stability and effectiveness.

Learn more about Azelaic Acid

BHT

Antioxidant, Masking

BHT is a synthetic antioxidant and preservative.

As an antioxidant, it helps your body fight off free-radicals. Free-radicals are molecules that may damage your skin cells.

As a preservative, it is used to stabilize products and prevent them from degrading. Specifically, BHT prevents degradation from oxidation.

The concerns related to BHT come from oral studies; this ingredient is currently allowed for use by both the FDA and EU.

However, it was recently restricted for use in the UK as of April 2024.

Learn more about BHT

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