How Long Does It Take For Skin Care Ingredients To Work?

So, you have just purchased the most recent skincare ingredients that you have heard the skincare community raving about, but how long will it be until you see results? How long does it take for skin care ingredients to work?

At what point do you accept that a skincare ingredient just does not seem to work for your skin? How long does it take for skin care ingredients to work for you?

Well, the short answer is – it depends!

How long a skincare ingredient takes to work depends on the skin care ingredient itself, as well as individual factors such as age, sex, and race. Furthermore, it can depend on what type of skin you are trying to treat (e.g. face or body), and it can even depend on the season!

To provide you with a more specific answer, we need to look at the biology of the skin as well as the scientific research behind individual skin care ingredients.

Skin Cell Turnover (Epidermal Desquamation)

Skin cell turnover occurs in the outer layer of the skin (the epidermis). It is an active process that happens without us knowing. The adult human sheds nearly a billion skin cells each day from the surface of their skin. It is the final stage of the skin cell differentiation process that lasts approximately 4 weeks^[1].

The human epidermis has four distinct sections; the basal layer, the spinous layer, the granular layer, and the stratum corneum.

In the basal layer, skin cells rapidly multiply and are initially attached to a basement membrane. These cells regularly detach from the membrane and move outward through the spinous layer and the granular layer until they are eventually shed by the stratum corneum.

This process is dynamic in that the surface skin cells are continually shed and replaced by inner skin cells that are developing and moving outward. In fact, within 4-weeks the basal cell is created, developed, and shed from the surface of the skin ^[2].

Factors That Affect Skin Cell Turnover

There are a number of different factors that can contribute to the rate of skin cell turnover. However, the research regarding this is conflicting.

For example, one study found that the rate of skin cell turnover was much higher in younger people than older people ^[3]. However, another study found no difference ^[4]. This may be due to the ages of participants in the study. It is well known that the cell turnover rate is much higher in babies and children due to the rate at which they grow. This rate then slows as we age. However, due to ethical considerations, most research participants tend to be over the age of 18 which may weaken the correlation.

It is often suggested that women shed larger skin cells than men ^[5] which would usually suggest a slower skin cell turnover in women. However, this appears not to be the case. In fact, there appears to be no discernable difference in the rate of skin cell turnover between men and women ^[6].

The research generally agrees, however, that the rate of skin cell turnover is affected by race, the location of skin, and season.

For example, darker skin types shed skin at a faster rate than lighter skin types ^[7], skin cell turnover is higher in summer than in winter ^[6], and skin cell turnover time is greater on the body than on the forehead ^[4].

How Does Skin Cell Turnover Affect How Long It Takes Skin Care Ingredients To Work?

Basically, you can usually start to see the benefits of a skincare ingredient once a full skin-cell turnover has taken place. As mentioned earlier, a full skin cell turnover takes approximately 4 weeks.

However, it may take longer to see the benefits of new skincare ingredients or products:

• The older you are
• The fairer skinned you are
• If you start using them in winter
• If you are using them on the body rather than the face
• If you are female (maybe)

In addition, the cell turnover rate can be affected by certain skin conditions. For example, the rate of skin cell turnover appears to be reduced in acne and is one of the contributing factors to the condition ^[8].

So, those are the main individual factors that affect how long it takes for skincare ingredients and products to work. What about the ingredients themselves and the skin conditions they are trying to treat?

Let’s take a look at some scientific studies to find out. We’ll focus on some of the most common skincare ingredients, such as retinoids, hydroxy acids, vitamin C, niacinamide, and hyaluronic acid.

How Long Does It Take For Skin Care Ingredients To Work?

A number of scientific studies were consulted to get a rough idea of how long to expect a skincare ingredient to work. It is important to note, however, that some studies only included one clinical assessment. For example, a study may have found significant effects of an ingredient after 8 weeks of use, but results may have been evident earlier if they had performed clinical assessments at, say, 2, 4, 6, and 8 weeks.

In addition, often in clinical research studies, the clinical assessments of skin improvements don’t necessarily match patient satisfaction rates. Basically, patients often don’t feel like they see improvements even when they’re objectively present.

Therefore, it is only possible to give a rough estimate of how long it will take for a skincare ingredient to work based on the evidence available.

How Long Does It Take For Retinoids To Work?

• 1% tretinoin increased collagen I formation after 10-12 months ^[9].

• 0.05% retinaldehyde cream and 0.05% retinoic acid cream reduced wrinkles and skin roughness after 18 weeks, with less pronounced reductions after 44 weeks ^[10].

• 0.05% tretinoin reduced eye wrinkles, crease lines around the mouth and the cheeks, wrinkling on the back of hands after 12 weeks of use. Epidermal thickness was increased after 12 weeks ^[11].

• Tazarotene 0.1% cream improved fine lines/wrinkling, hyperpigmentation, pore size, elasticity, roughness, and overall photodamage after 24 weeks. Results for fine wrinkling and hyperpigmentation were seen as early as 2 weeks of treatment. After 8 weeks of treatment, pore size, elasticity, and overall photodamage were improved. Improvements in skin roughness were seen after 16 and 24 weeks. After 24 weeks of use, no significant difference was found for course wrinkling, broken capillaries, or actinic keratosis ^[12].

• Varying strengths of tazarotene cream (0.1%, 0.05%, 0.025%, and 0.01%) and 0.05% tretinoin resulted in significant improvements in fine wrinkles and hyperpigmentation after 24 weeks ^[13].

• Tazarotene 0.1% gel, adapalene 0.1% gel, tretinoin 0.1% microsponge, tretinoin 0.025% gel all significantly improved inflammatory acne after 12-15 weeks ^[14].

• Tretinoin gel 0.1% and adapalene gel 0.1% significantly decreased the number of acne lesions after 12 weeks. Tretinoin 0.1% gel significantly reduced comedones after 4 weeks of use ^[15].

• Tazarotene 0.1% gel significantly reduced the number of non-inflammatory acne lesions after 12 weeks of use. Tazarotene 0.05% significantly reduced non-inflammatory and total acne lesion counts after 8 and 12 weeks ^[16].

Based on this research, we can come to the following estimates:

• Retinoids can improve wrinkles in 12 – 24 weeks (some people may see results as early as 2 weeks).
• Retinoids can improve acne in 4 – 12 weeks.
• Retinoids can improve hyperpigmentation in 24 weeks (some people may see results as early as 2 weeks).

How Long Does It Take Hydroxy Acids To Work?

• 25% AHA (either glycolic acid, citric acid, or lactic acid) significantly increased skin thickness, improved quality of elastic fibers, and increased density of collagen after 6 months of use ^[17].

• Glycolic acid, lactic acid, and citric acid can increase collagen I and procollagen I after 6 weeks ^[18].

• 8% glycolic acid and 8% lactic acid improved photodamage as skin sallowness after 22 weeks. *% lactic acid also improved hyperpigmentation and roughness after 22 weeks ^[19].

• 20% glycolic acid significantly increased epidermal and dermal hyaluronic acid and collagen gene expression after 3 months of use (it is not mentioned whether this resulted in visible improvements) ^[20].

• 10% glycolic acid improved acne significantly by day 45 of a 90-day trial ^[21].

• A facial wash containing 2% salicylic acid significantly improved acne after 2 weeks of use ^[22].

• 2% salicylic acid pads significantly reduced total acne lesion count after 4, 8, and 12 weeks of use. Non-inflamed lesions were significantly reduced after 8 and 12 weeks of use. Inflamed lesions were significantly reduced after 12 weeks of use ^[23].

Based on this research, we can estimate that:

• AHA’s can increase collagen in 6-42 weeks
• BHA’s can improve acne in 2-4 weeks

How Long Does It Take Vitamin C To Work?

• A vitamin C formulation of 10% ascorbic acid and 7% tetrahexyldecyl ascorbate significantly improved wrinkles after 12 weeks of use ^[24].

• A cream containing 5% vitamin C significantly improved skin hydration, firmness, laxity, suppleness, hyperpigmentation, roughness, imperfections, and dryness after 6 weeks of use ^[25].

• Topical ascorbic acid significantly improved fine wrinkling, roughness, coarse wrinkles, skin laxity, sallowness, and overall features of photodamage after 3 months of use ^[26].

Based on this research, we can estimate that:

• Vitamin C can work within 6-12 weeks
• Vitamin C can improve wrinkles after 12 weeks
• Vitamin C can improve skin hydration and reduces pigmentation in 6 weeks

How Long Does It Take Niacinamide To Work?

• 5% niacinamide significantly decreased hyperpigmentation in 4 weeks. 2% niacinamide significantly lightened skin after 4 weeks ^[27].

• 5% niacinamide significantly improved fine lines/wrinkles, hyperpigmentation, skin texture, red blotchiness, and skin yellowing/sallowness after 12 weeks ^[28].

• 2% niacinamide significantly reduced sebum levels in Japanese patients after 2 weeks and 4 weeks of use. 2% niacinamide significantly reduced sebum level in Caucasian patients after 6 weeks ^[29].

• 2% niacinamide significantly improved skin barrier function, reduced TEWL, increased skin hydration, and reduced facial erythema in 4 weeks ^[30].

• 4% niacinamide significantly improved eye wrinkles after 8 weeks of use ^[31].

• 4% niacinamide significantly improved hyperpigmentation after 8 weeks of use ^[32].

• 4% niacinamide significantly reduced pore size and improved skin evenness after 8 weeks of use and improved wrinkles after 12 weeks of use ^[33].

• 4% niacinamide gel significantly decreased pustules, comedones, and papules after 8 weeks of use. 4% niacinamide improved inflammatory acne and reduced the number of acne lesions and acne severity after 8 weeks of use ^[34].

Based on this research, we can estimate that:

• Niacinamide can improve hyperpigmentation in 4 weeks
• Niacinamide can increase skin hydration in 4 weeks
• Niacinamide can reduce erythema in 4 weeks
• Niacinamide can reduce sebum levels in 2 – 6 weeks
• Niacinamide can improve acne in 8 weeks
• Niacinamide can improve wrinkles in 8 – 12 weeks

How Long Does It Take Hyaluronic Acid To Work?

• Nano-hyaluronic acid resulted in a significant moisturizing effect after 2, 4, and 8 weeks of use, significantly firmer skin after 2 weeks, significant improvement in skin elasticity after 2 and 8 weeks. After 8 weeks it resulted in a significant decrease in the depth of wrinkles, improved skin hydration, firmness, and elasticity ^[35].

• 1% hyaluronic acid significantly improved skin hydration and elasticity after 60 days of use. Low-molecular-weight (LMW) hyaluronic acid resulted in a significant reduction in wrinkle depth after 60 days ^[36].

• Hyaluronic acid instantly improved the appearance of fine lines and wrinkles and improved skin hydration after 15 minutes of application. After 8 weeks of use, there were significant improvements in fine lines/wrinkles, skin roughness, and skin hydration ^[37].

Based on this research we can estimate that:

• Hyaluronic acid can improve skin hydration in 15 minutes
• Hyaluronic acid can improve fine lines and wrinkles in 8 – 9 weeks

Summary

Overall, it appears that the majority of skin care ingredients will take at least 4 weeks of use before any results are seen due to the cell turnover process discussed earlier.

In addition, most skin care ingredients that target fine lines and wrinkles take at least 8 weeks to provide improvements, although it is usually closer to 12 weeks to see significant results. This is likely due to the fact that it takes approximately 3 months for collagen changes in the dermis to take place.

Furthermore, some skincare ingredients can provide immediate effects, but these effects are temporary and are generally due to increased hydration levels in the skin.

Finally, the length of time it takes a skin care ingredient to work depends on the ingredient, what it is treating, as well as individual factors.

In general, though:

Retinoids take 4 to 24 weeks to work

AHA’s take 6 to 42 weeks to work

BHA’s take 2 to 4 weeks to work

Vitamin C takes 6 to 12 weeks to work

Niacinamide takes 2 to 12 weeks to work

Hyaluronic acid takes 15 minutes to 9 weeks to work

Do these time frames match your experiences? Let us know in the comment section!