Tag: skincare

Comparison of skin hydration in combination and single use of common moisturizers (cream, toner, and spray water)

KindofStephen

What’s the best way to organize your skincare routine? Should we layer from thickest to thinnest? Where does sunscreen go?

I’ve been asked this a lot and I don’t have the answer. Most research on skincare application is done with just one product. Sunscreens are always tested on clean skin with no other products. If you want to get as close to the protection on the label, it’s best to recreate the conditions it was tested on, which means applying it on clean skin and not following it with anything else. The same applies for most cosmetic products as well.

That’s not realistic for everyone and many of us enjoy using multiple products. But the reality with a lot of the advice found online and from experts is that it’s just advice and often isn’t based on evidence – especially scientific evidence.

A group of Chinese researchers performed an experiment looking at the effect of different combinations of three products (moisturizer, toner, and mineral water sprays) and different application routines on skin moisture. Keep in mind that the only endpoint measured was stratum corneum moisture measured by the Corneometer, a capacitance measuring tool often used in cosmetic research. This experiment doesn’t provide any insight beyond skin moisture, like skin penetration of an active affected by combination or routine, for example.

20 female volunteers participated in this experiment. Eight 3-by-3 cm squares were drawn on the legs and forearms of each volunteer and were randomized to receive eight different routines and combinations – including a square with no product applied, acting as a control. The baseline moisture levels of the squares were measured and categorized into ‘normal’ or ‘dry’ by a limit of 35 a.u. (a measurement unit used by the Corneometer).

The 8 different combinations and routines are as follows;

Toner and Toner reapplied every 2 hours (T-T)
Cream then Toner together (C+T)
Toner only (T)
Cream only (C)
Cream then Water reapplied every 2 hours (C-S)
Untreated (Control)
Cream and Toner reapplied every 2 hours (C-T)
Toner then Cream together (T+C)

Stratum corneum moisture levels were measured every 2 hours, including a baseline, and participants were kept in a 22 °C room with a 50% humidity.

The products included in the test were a Winona brand Cream with the ingredients:

Aqua, Glycerol, Butyrospermum Parkii Oil, Dimethicone, Glycereth-26, Tridecyl Trimellitate, Pentylene Glycol, Hexyldecanol, Sucrose Polystearate, Diethylhexyl Cyclohexane, Petroleum Jelly, Tocopheryl Acetate, Prinsepia Utilis Royle Oil, Portulaca Oleracea Extract, Beta Glucans, Sodium Hyaluronate, Cetylhydroxyproline Palmitamide, Alpha Bisabolol, Cetearyl Alcohol, Hydrogenated Polyisobutene, Acrylamide, Acrylamide/ammonium Acrylate Copolymer, Acrylates/c10-30 Alkyl Acrylate Crosspolymer, Tween 20, Xanthan Gum, Disodium Edta, Polybutene, Polyisobutene, Butyl Stearate, Stearic Acid, Phenoxyethanol, Ethylhexylglycerin

a Winona brand Toner with the ingredients:

Aqua, Pentylene Glycol, Glycerol, Glycereth-26, Trimethylpentanediol/adipic Acid/glycerin Crosspolymer,
Portulaca Oleracea Extract, Beta Glucan, Sodium Hyaluronate, Hydroxyethyl Cellulose

and Avene Thermal Spring Water was used as the Mineral Water Spray.

While applying any form of skincare product created an increase in skin moisture in dry and normal skin, some combinations were significantly more effective than others.

Table VI is mislabeled and is the data for Dry Skin

Because the normal or dry categories were determined by Corneometer, there’s no way to self-categorize unless you have a Corneometer handy.

From this experiment, the increase in moisture from Cream then Toner, or Toner then Cream, or Cream only were about the same. This implies that the total amount of cream and toner applied is more important than the order of application. As well, this also implies that the increase in moisture is mostly from the cream and not the toner.

The researchers speculate that the increase in moisture reaches a peak depending on factors like the environment which slowly declines after application. Toner on its own did increase moisture of the skin, but even when combined with cream never surpassed the moisture gained from cream alone.

In terms of supplementation of Cream with Water or Toner, the greatest increase in moisture was achieved with application of a Cream then Toner every 2 hours. Supplementation of Water after Cream application reduced skin moisture with each application. Toner with additional Toner supplementation increased skin moisture over time, but was still less than Cream and Toner.

I think reading descriptions of the effects is likely a bit confusing, so I encourage you to use the interactive charts to compare different applications.

Also keep in mind that this experiment used three specific products and concentration of ingredients will vary between products. So it’s best to use this information as a guideline, but not a rule.

Li Yuanxi, Wei Hua, Lidan Xiong, Li Li, Comparison of Skin Hydration in Combination and Single Use of Common Moisturizers (Cream, Toner, and Spray Water), Journal of Cosmetic Science (2016), PMID: 29394018

Galderma Announces FDA Approval of 0.1% Differin® Gel For Over-the-Counter Acne Use

KindofStephen 1 Comment

Galderma Announces FDA Approval of 0.1% Differin® Gel For Over-the-Counter Acne Use

What is Differin?

Differin is a topical acne treatment which contains a synthetic retinoid called adapalene. Adapalene is not similar in structure to tretinoin or other retinoic acid compounds. However, like other synthetic retinoids like tazarotene, adapalene activates the same receptor targets in the skin like retinoic acid receptor (RAR) β and γ and retinoid X receptor (RXR).

Adapalene is more stable than tretinoin and can be used in conjunction with benzoyl peroxide. It is also more lipophilic, so more can accumulate within the sebaceous unit.

Differin for Acne

In a head to head comparison, 0.100% adapalene gel  was more effective than a 0.025% tretinoin gel in non-inflammatory (open and closed comedones) and inflammatory (papules and pustules) acne – it was better tolerated as well, which means less irritation.

A multi-ethnic study with Chinese, Malay, Indian, and Caucasian subjects found good tolerability among all races. A separate study on Black South Africans also found efficacy in treating acne and good tolerability.

A meta-analysis of 5 studies that compared 0.100% adapalene gel and 0.025% tretinoin gel also found them similarly effective for acne. Of particular interest, it seems adapalene begins to reduce acne after 1 week of use – which is faster than tretinoin and may be due to adapalene causing less irritation.

Another study showed that 0.1% adapalene gel was less irritating than 0.100%, 0.050%, 0.025% tretinoin and even 0.100% tretinoin microspheres (Retin-A Micro).

A study comparing 0.030% and 0.100% adapalene gel found that the 0.100% adapalene gel was significantly more effective than the 0.030% gel in treating acne.

A supplementary article submitted to Cutis reported a decrease in sebum production on subjects that were using 0.100% adapalene gel for 4 weeks. Sebum production returned to normal after the treatment was stopped. There’s a possible mechanism for adapalene to reduce sebum production by suppressing triglyceride formation in sebocytes – in hamsters.

Differin for Hyperpigmentation

Adapalene seems to also be effective for hyperpigmentation, however there is more research and evidence supporting tretinoin and tazarotene.

A non-blinded study on 65 Black African patients using a 0.100% adapalene gel found significant improvements in hyperpigmentation. Less than 5% of subjects in the study experienced skin irritation.

Studies covered in the next section on Caucasian and Chilean subjects also found brightening in overall skin pigmentation.

Differin for Anti-Ageing

In terms of treating photodamage and photoageing, there is very little research on the topic, especially compared to tretinoin and to a lesser extent tazarotene.

A Galderma study with 0.100% and 0.300% adapalene gel on 90 Caucasian subjects saw improvement in solar lentigines (freckles) and actinic keratoses. Trained dermatologists noticed an improvement in fine skin wrinkling and an overall brightening of the skin’s pigmentation. No significant change in deep wrinkles was noticed. Results were much more pronounced with the 0.3% adapalene gel.

Another Galderma study on Chilean women found similar results. They found marked improvement in skin wrinkling at 90 and 180 days of treatment using a Visia skin analyzer, though they did not differentiate between fine and deep wrinkles. Of interest is that skin thickness did not increase, which is common with tretinoin treatment, however they did find an improvement in abnormal elastin accumulation (elastosis band) in the skin.

Questions and Answers

I’ve gotten a few questions about this on my Instagram, so here they are with their answers!

pricklygoldenpear asks: Can adapalene and other retinoids be used with niacinamide? I mean like layering them. If yes, which one over or under – or are both ways OK?

As with many questions regarding ingredient compatibility and order of application – there’s very little to often no research on the topic. Almost every skin study compare one treatment vs a control treatment. Very rarely do studies look at results from one ingredient, then an additional ingredient, etc. This type of study design is significantly more complex, more time-consuming, and costly to perform.

When looking for studies that examined niacinamide and retinoids, I found none that looked at the combination of niacinamide and tretinoin or adapalene.

A study published in the JCD did compare the use of a retinyl ester (hydroxypinacolone retinoate) with niacinamide, and found an improvement in melasma, however the control cream was just a gel – so we can’t tell which ingredient in particular was responsible for the benefits.

A supplementary article submitted to the JAAD looked at a combination of niacinamide with retinaldehyde and glycolic acid and also found improvements. Again it suffers from the same problem as the previous study – which ingredient was responsible? Were the effects synergistic?

And an open-access paper comparing the combination of niacinamide, two peptides (Pal-KT and Pal-KTTKS), and retinyl propionate found it produced similar effects to 0.02% tretinoin – with less dryness and irritation.

A study published in CCID found that the combination of niacinamide, retinol, and 7-dehydrocholesterol reduced metalloproteinase and other inflammatory markers in the skin.

An in-vivo study on cultured human keratinocytes found that niacinamide could reduce some of the increased expression of aquaporin-3. This increase of aquaporin-3 is thought to increase water permeability – which could lead to skin dryness.

So while none of these studies looked niacinamide and adapalene or tretinoin directly, it seems likely that there should be no issue combining the two.

As to the “proper” ordering of the two topicals, there is no data and I don’t think it really matters. Choose the product with the lowest lipid content first, but above all else: Consistency matters more than product application order.

elspethxieI asks: Is this suitable for mothers who are breastfeeding?

From Medications’ and Mothers’ Milk by Thomas Hale, “Differin Gel (Adapalene 0.1%) is similar to Retin-A (retinoic acid or tretinoin)…Adapalene is virtually unabsorbed when applied topically to the skin. Plasma levels are almost undetectable, so milk levels would be infinitesimally low and probably undetectable.”

Using a Carbon-13 NMR for quality control…

KindofStephen

This is an auto sampling carbon NMR!

This machine can help you identify organic materials based on signals from carbon atoms. Carbon-13 nuclei have a “spin”, and this machine can read signals produced after the nuclei are subjected to a strong magnetic pulse.

This is just one of the techniques we can use to identify and test the quality of material. Unfortunately a piece of paper from a supplier saying the material is of high quality…just isn’t enough! As cosmetic chemists we have our clients’ health and skin as our responsibility, so it’s important to make sure that the material going in to our products are what they’re supposed to be, as pure and high quality as possible, and pathogen and contaminant free.

The FDA recently reported a fungal contamination of eye shadows from a small company, as well as unacceptably high levels of lead in a bentonite clay product – marketed for babies.

Sure, it’s a little bit of time and money spent on doing your own quality control….but can you put a price on your clients’ trust and health?

Yesterday I had some samples of hyaluronic acid tested. I wanted to make sure that the material was of high quality, free of heavy metal contaminants and pathogens, and was actually hyaluronic acid

I’ve heard horror stories of suppliers (and repackers) passing off other material as more expensive material. One person told me that they had received an order of product and only the top layer was what it was supposed to be! The rest of the container was just cheap filler!

image

There’s only one way to prevent these kinds of oversights… and that’s constance vigilance…in the words of Alastor Moody!

And it’s not just the cosmetics industry…Consumer Reports did an experiment a few years ago and found that only 20% of the fish they bought at restaurants and markets were actually the labeled species

Did some cleaning in the lab, and found this!

KindofStephen

This is a self sealing, airless, and metered dose dispensing system. The bag doesn’t leak product when squeezed, but when the button is pressed…it dispenses the same amount of product each time (or at least close). It was designed to deliver skincare products and drugs.

Sadly the company is no longer in business and this is probably one of the last prototypes sitting around. As a testament to its storage ability I think this one is almost 9 years old!

Here’s the original press release announcing the product:

Poly-D’s MDS patented pump and valve dispensing mechanism allows for easy, one-handed dispensing of an exact amount of product with viscosities up to 50,000cps.

The vacuum-based technology means the pump forces it out of the pouch (98% of it) in a neat and clean manner, and because it is a vacuum-based technology, it works in any orientation.

The MDS valve only opens when the button is pressed and then seals tight upon release, eliminating the need for caps and closures.

It can be used as a stand-alone dispensing package or integrated into applicators or custom-designed devices.