Most people with a cursory knowledge of skin care will recognize the term "retinoid", or at least retinol, as a useful ingredient in reducing the appearance of fine lines, scarring, and even acne. 

Retinol is commonly found in over-the-counter skincare products. But the retinoid family is much larger than just retinol.

Read Nava MD's Definitive Guide To Retinoids

Retinoids are all forms of vitamin A, some synthetic and some natural, and they all help with a more youthful appearance by accelerating the skin cell turnover process and improving elasticity. 

Tretinoin was one of the first retinoids approved by the FDA for the treatment of acne as Retin-A® (0.1%, 0.05%, or 0.025%  tretinoin), and for the treatment of photoaging (or the wrinkles, dullness, etc. that come with years in the sun) as Renova® (0.02% tretinoin). 

Other retinoids include retinol, retinal, and retinaldehyde all over-the-counter, while prescription options include tazarotene and isotretinoin.

Tretinoin is now available in myriad concentrations generically from a variety of manufacturers, but what are the concentrations that work best?

Tretinoin Percentages and Photoaging

Individuals who have spent much of their life exposed to sunlight without using sunscreen often develop prematurely wrinkled skin that is coarse, lacks elasticity, and is frequently unevenly toned.

Tretinoin is all-trans retinoic acid (ATRA), an active vitamin A metabolite and the substance that your skin uses most readily. Retinol, by contrast, must be converted through skin processes into the active form of retinoic acid.

Tretinoin is an effective alternative to injectables as a noninvasive cosmetic treatment for improving the signs of photoaging.

Topical retinoids like tretinoin have been extensively investigated for treating signs of photoaging. Results of numerous studies show that topical tretinoin can be used to reduce mild to severe wrinkling, skin roughness, and skin discolorations due to long-term sun exposure. Most people using tretinoin for photoaged skin need to apply the cream to their face daily for several weeks before improvement is visible. No major adverse effects have been reported in people using tretinoin as a long-term treatment for photoaged skin. However, dermatologists may lower the concentration (or percentage dose) of tretinoin depending on tolerability.

Why is Tretinoin So Effective for Treating Signs of Photodamage at Any Strength?

Tretinoin belongs to the large class of retinoids, proven to reduce signs of photoaging. Retinoids stimulate collagen production, exfoliate the skin by naturally removing old skin cells, and promote the development of new skin cells. The reason why some people experience side effects like stinging, redness, and peeling is because tretinoin works quickly to exfoliate and generate new cells. 

Tretinoin and other retinoid topicals are also used to reduce acne outbreaks by performing the same accelerated, healing turnover processes on acne-prone or oily skin.

What Percentage of Tretinoin is Effective?

One longitudinal, placebo-controlled study found that 0.02% tretinoin significantly improves both coarse and fine wrinkles within four months of use compared to a placebo. Participants in the study presented photodamaged skin ranging from mild to severe. Those with more severe photodamage took several weeks longer to see improvement in their skin. Notably, when participants applied lower concentrations of tretinoin, at .001% and .01%, these percentages of tretinoin were no more effective at reducing signs of photoaging than the placebo.

A review of two double-blind clinical studies involving 0.02% tretinoin for photoaging also found that this percentage of tretinoin provided a "statistically significant improvement" in the participants' skin yellowing, fine wrinkling, and coarse wrinkling. Desired results were achieved by the end of 24 weeks and minimal side effects were reported. The authors of the study stated they conducted this review to investigate whether 0.02% tretinoin presented the same results as 0.05% tretinoin. 

They concluded that both dosing percentages were safe and effective treatments for signs of moderate to severe photoaging in facial skin.

Another placebo-controlled study published in the American Journal of Clinical Dermatology had subjects apply 0.05% tretinoin cream to their moderate to severe photodamaged skin. The results showed that 0.05% tretinoin significantly improved wrinkling, sallowness, and mottled hyperpigmentation compared to the placebo. Researchers involved in the study concluded that "long-term treatment with 0.05% tretinoin emollient cream is a safe and effective protocol for adults with moderate to severe facial skin photodamage."

Low-strength and High-strength Tretinoin

Early studies conducted in the 1990s of different tretinoin percentages evaluated the tolerability and effectiveness of 0.025% and 0.1% tretinoin cream. Researchers found that both 0.025% and 0.1% tretinoin significantly improved signs of facial photodamage, with the stronger 0.1% tretinoin providing the same results. However, the 0.025% tretinoin did not cause as many incidences of side effects as the 0.1% tretinoin.

Side Effects of Tretinoin

All topical retinoids may cause various forms of skin irritation. The most common side effect of tretinoin is a "retinoid reaction" also sometimes called a retinol purge or tretinoin purge. Characterized by a burning sensation or irritation where the cream is applied, itchy skin (pruritus), peeling, and red rash (erythema), a retinoid reaction typically emerges within the first two to three weeks of using tretinoin. Most cases of retinoid reaction are dose-dependent and can be alleviated by lowering the tretinoin percentage and taking steps to moisturize. Some patients may find it useful to start with treatment every other day, increasing to daily as their skin acclimates.

Photosensitization (sensitivity of the skin to sunlight) often occurs within several days of starting treatment too. Adverse effects of photosensitivity can be avoided by staying out of the sun, using sunscreen when going outside, or by applying tretinoin at night. After two or three months of using tretinoin, the skin's response to sunlight generally returns to normal.

Tretinoin has been studied for over 30 years and there have been no incidences of long-term or systemic side effects. However, dermatologists advise pregnant women to avoid using any retinoid due to a possible risk of harm to the fetus.

What Percentage of Tretinoin Should I Use?

Dermatologists generally recommend the following tretinoin percentages to treat facial photoaging:

Use 0.05% tretinoin initially (if adverse effects do not cause discontinuation), possibly followed by another year of 0.02% tretinoin.

This regimen is not always suggested, however, and is subject to variation as prescribed by dermatologists after evaluating a patient's skin condition. 

Thirty minutes before applying tretinoin, wash facial skin with mild soap and pat dry. It’s common to feel a stinging and/or warm sensation after applying the cream, especially if the skin is not completely dry.

Do not wash your face or use other skin products for one hour after applying tretinoin. Using more than a pea-sized amount of tretinoin can cause "pilling" of the cream, too, in which too much skin cream prevents it from being absorbed fully by the skin. 

Tretinoin works best when used in conjunction with a comprehensive skincare program involving sunscreen, high-quality moisturizers, and even lifestyle changes like skin-friendly foods, drinking plenty of water, and exercise.

Can I Get Tretinoin Online?

Tretinoin requires a prescription and is generally only available from a licensed doctor or dermatologist. 

And yes, you can get tretinoin online.

At Nava MD, we connect people like you with a licensed dermatologist online, for custom prescription skincare formulas delivered to your door, if prescribed. With our short online consultation, your Nava MD provider can evaluate your condition from anywhere, prescribe the right formula for you (containing the right concentration of tretinoin), and have your formulation sent to your door. You can reach your prescriber any time for follow-up questions through our Member Portal, and refills are sent as you need them. 

It’s easy and affordable. Get started with Nava MD to find out if tretinoin is right for you.