On 7/26/2014 HonnyBrown said: pHs are on a logarithmic scale. The pH of skin won't change with a toner.
I haven't used toner since I started using Olay. They don't have toner in the Regenerist line. I don't miss it, but I don't wear foundation either.
The fact that it is a logarithmic scale does mean that each whole number represents a tenfold change over the previous number. But that doesn't mean that a product can't affect that number and have an impact.
Here is one of the best analyses of pH and skin in terms of producs:
The initials pH stand for “Power of Hydrogen†or "Potential of Hydrogenâ€. Both terms are correct. This is a measure of the hydrogen ion content in a solution.
The pH scale measures how acidic or alkaline a product is, compared to pure distilled water (which is pH 7.0). Only wet substances have a measurable pH. The skin's pH is actually the pH on the skins surface from the moisture within the skin, and the "acid mantle" which is part of the protective "barrier" on its surface. Hair for example has no pH.
The acid mantle is a fine film layer, slightly acidic, made up from skin oils, sweat, and dead cells. It is one means the skin uses to protect itself from bacteria, moisture loss, and environmental damage. Pollutants, harmful bacterium, contaminants are normally alkaline in nature, so a slightly acid skin surface helps fight off these harmful elements and prevent them from entering into, and damaging the skin. Maintaining the acid mantle is recommended for good skin health. When the acid mantle is damaged it takes approximately 14-17 hours to repair itself (assuming no other damaging products are applied to it).
A damaged acid mantle leads to a number of skin issues, such as over dry skin, dehydration, over oily skin, flaky skin, acne, sensitivity, etc. It would require another long post to detail all this. But incorrect pH products can contribute to acid mantle degradation, and increases in acne-causing bacteria on the skin. (More on this below)
The pH Scale
The pH scale goes from 0-14. This covers most wet substances, and certainly all skincare products.
-Acids have pH values under 7 - they are more acidic then water (acid)
-Alkalis have pH values over 7 - they are more alkaline then water (base)
-If a substance has a pH value of 7 - it is neutral, like water (neither acid nor base)
The difference between each whole-value pH level represents a tenfold change. (For example, a cleanser with a pH of 6 is ten times more alkaline than a cleanser with a pH of 5, and a cleanser with a pH of 7 is 100 times more alkaline then one of 5.) Because of this, only a few units of pH can make a big difference in how your skin reacts to a product.
Some pH examples:
pH 1 = Battery acid
pH 1.5 -2 = gastric (stomach) acid
pH 2 = lemon juice
pH 2.5 = cola soft drinks
pH 3 = vinegar
ph 3.5 = orange juice
pH 4.6-5.5 = healthy skin (and recommended pH range for your cleanser, for best skin health)
pH 5.5 = rainwater (pure water, when exposed to the atmosphere, will take in carbon dioxide, changing its pH)
pH 6.5 = milk
pH 6.5 – 7.4 = healthy saliva
pH 7 = pure distilled water - (This is neutral pH, neither acid nor base)
pH 7.35 – 7.45 = human blood
pH 8.5 = baking soda (damaging to skin's acid mantle)
pH 9 = seawater
pH 9.0-10.0 = hand soap, detergents (very damaging to acid mantle)
pH 10.5 = Milk of Magnesia
pH 11.5 = household ammonia
pH 12.5 = household bleach
pH 13 = lye (sodium hydroxide, or Draino)(Alkaline or Base extreme)
Skin and the Acid Mantle
Newborn baby skin has a neutral pH of 7. Within a few months it adjusts to a more "normal" pH of 4.5 to 5.5, enabling it to be more resistant to bacteria.
Adult skin is normally slightly acidic, a range of 4.5 to 5.5. Different body areas can differ in pH, and disease and acid mantle damage can alter pH. But the preferred range for facial skin pH is 4.5 to 5.5.
Those with skin disease, skin problems, and stressed skin usually have a skin pH over 6.0. Aged, stressed and damaged skin have more difficulty maintaining a “correct†pH.
As skin pH is elevated closer to pH 7.0, it becomes less and less able to function optimally and to kill bacteria. This allows acne-causing bacteria to multiply rapidly on the skin's surface. (Acne bacteria are found on everyone’s skin, even if you never have a pimple in your life.) The damaged skin is unable to fend off the excess bacteria, and they multiply rapidly. Bacteria growth is very slow at pH of 5.5 or less, but a slight shift upward, toward the alkaline levels, causes a marked increase in the reproduction and lifespan of acne-causing bacteria.
So if your skin is at a higher pH (anything over 6, as damaged skin often is) the acne-causing bacteria can multiply much easier and faster -- often faster then your skin can handle. Skin pH is one main contributor to acne.
Skin pH also has an effect on how easily irritated your skin is, how well it ages, and how it deals with product and environmental stress. This is why it is recommended that you cleanse skin with mild, non-irritating products, as close to the skin's natural pH as possible.
Many commercial cleansers are highly alkaline, which also changes the skin's pH to alkaline levels on the skin surface, for a short time. Many alkaline cleansers are in the same pH range as baking soda, and some are nearly as high as ammonia. This is very harsh on the skin, and can lead to increased irritation, acne, moisture loss, skin aging etc. As pimples erupt, the skin is less able to heal itself, or the damage that pimples leave behind.
If a product has a high pH and a considerable percentage of a strong detergent such as sodium lauryl sulfate, or irritant like peppermint oil or menthol, because of the pH destructive activity on the acid mantle, the detergent can contribute to even more damage then it would if the product pH was closer to 5.5. It literally takes a split second for an alkaline product to degrade the skin barrier enough for an irritant or damaging detergent to penetrate. Some people can handle this better then others, but long term daily use on the skin can contribute to long term issues on all skin types. As skin ages, or the barrier function degrades, it has more difficultly dealing with this type of stress.
Even when the skin re-adjusts to its more normal pH (4.5 to 5.5) - it is already damaged, irritated and stressed. The damage recovery involves longer term healing; 14 to 17 days for acid mantle repair. Continued long-term damage, stress, and mild irritation can prevent the skin from maintaining its best pH level of 4.5 to 5.5. With time, and increased damage, it may tend to stay at the 6 range or higher.
As skin become healthier, its pH values lower, and acne growth also lowers. The skin becomes more "normal" and regulated.
Listing of pH of many common cleansers:
Burt’s Bees Tomato, Carrot, and Lettuce soaps 10
Dial Soap (liquid and bar) 9.5
Dove Bar, Baby Dove Bar 7
Johnson & Johnson Head to Toe Baby Wash 6.5-7.0
Neutrogena Facial Cleansing Bar Original Formula 8.7-9.2
Paula’s Choice (all formulations) 5.5
A product may include the term “pH Balanced†on the label. This does NOT mean that it has an optimal pH of 5.5. The term has no legal definition.
Some products are a good pH, but high in irritants. Which is better then high pH and high irritants, but not great either.
A good cleanser cleans the skin without breaking down the acid mantle, or adding irritants to the skin. It is mild with a 5.5 or lower pH.
Layering Products and Wait Times
pH affects the acid you use and how it works. Another consideration is not to disturb an acid while it is on your skin, which can alter pH and affect its action on the skin.
Generally speaking an acid is effective for approximately 20 to 30 minutes on the skin surface. After that point the skin pH has risen enough to lessen the exfoliation action on the skin, and the acid is effectively neutralized. During this 30 minute time frame, the acid is working at effective levels. Anything applied after 30 minutes will not hamper the effect of your acid, as the pH has already changed, and the acid action has slowed a lot.
Acids that are a high (peel) percentage such as 30% and 40% and above are more concentrated. Therefore their activity can continue for longer, so their action should be stopped at appropriate time with the use of a base rinse (baking soda and water) or a mild detergent cleanser. This will effectively halt the exfoliation action, by raising the skin pH.
Washing the skin with an cleanser of pH over 5.5 can slow or lessen the effect of your acid, because the acid must now deal with the high pH level on the skin. The bigger the range difference, the more this will affect your acid action, especially in the case of acids at 2.0 pH or less. So if you use a high pH cleanser, you should wait 30 minutes before using a pH-dependent product, to allow the skin to regulate its pH down to about 5.5. Or you can use an acidic toner to adjust the pH of the skin down before applying the product.
Most commercial astringents and toners contain high levels of irritants such as alcohols, Witch Hazel, Menthols, Mint oils, etc. These should be avoided, as they can damage the skin barrier. If you want to use a toner to adjust pH to lower levels, either use a liquid acid like Paula’s Choice BHA or AHA liquid first, or a very dilute mixture of Apple Cider Vinegar and distilled water. Vivant's Mandelic Acid toner is another good option, though it is expensive.
The best option is simply to use a cleanser with a pH of 5.5.
If you use a BHA product with 3.2 pH, then immediately apply a treatment product on top with 6.5 pH, the exfoliation action of your BHA is reduced by 75%. So applying a higher pH to your pH dependent acid will neutralize it sooner, or stop its action at the point you added the higher pH product.
Other products are also pH dependent. L-Ascorbic Acid forms of Vitamin C are pH dependent. For good stability and effective action, a good Ascorbic acid product is about 2.0 pH. Since Vitamin C absorbs faster into the skin, you can generally have a shorter wait of about 10 to 15 minutes.
Some Good General Rules
(This info comes from DebbieNIR, former host of the Diana Yvonne Skin Care Board. The original post is now gone.)
1. Use a mild, non-irritating, detergent-free cleanser with a 5.5 pH or lower.
2. If your cleanser pH is higher then 5.5, wait 15 to 30 minutes after cleansing to use a low pH AHA or BHA. (Or use a toner to acidify the skin first.)
3. Acids should be applied to freshly cleansed skin.
4. Both acid percentage and product pH must be used to factor total effective acid amounts. (FAV)
5. If using AHA and BHA together, always apply AHA first (after cleansing) – UNLESS the BHA solution pH is equal to or lower than your AHA. In this case, apply the BHA first, because it penetrates skin oils better, and will enhance the AHA effectiveness.
6. Acids can be used in many different ways – which affect wait times.
a) If a 2% or 5% BHA product is used, and rinsed off, WAIT until it is rinsed off to proceed with other products. (BHA washes are less effective than leave-on products.)
b) If a 2% or 5% BHA product is applied and left on the skin, but no AHA product is following, wait 30 minutes before applying next product. This allows the BHA to work at its most effective, and exfoliate at optimal levels.
c) If a 2% or 5% BHA is applied and left on the skin before a rinse-off AHA, you do not need to wait to apply the AHA – IF the pH of both products is similar and compatible. If you rinse the AHA off after 5 minutes of application (over the BHA) you have also stopped the BHA action at 5 minutes. Both should have a lower effective pH. If the AHA has a higher pH, it will also raise the pH of the BHA, affecting its action also.
d) If a 2% or 5% BHA is being left on the skin, before a leave on AHA, you don’t need to wait to apply the AHA. Apply BHA, then AHA, then wait a total of 30 minutes with both products layered, then proceed to next product application. (This is assuming that both acids have a low pH.)
e) Do not apply a higher pH BHA before a lower pH AHA. The higher pH product will hinder the lower pH product. Wait 30 minutes between both acids, applying the lowest pH first.
f) If using a higher BHA after a lower AHA product, apply lower pH AHA first. Wait 30 minutes for it to work. Then apply higher pH BHA on top, and wait 30 minutes for the BHA to work. Then apply other products on top.
g) If you need to rinse products off sooner then 30 minutes to shorten activity and lessen irritation, you can rinse with water, before proceeding to the next step. If using a high strength AHA or BHA, at strong “professional†peel level strength, you will neutralize product with baking soda and water, and rinse off before proceeding to your next step.
h) Apply low pH before high pH.
Layering Other Products
This information is also from DebbieNIR's posts on the Diana Yvonne Skin Care Board.
Retinols, Retinoids, Vitamin A products
These products are often pH dependent. Apply to clean dry skin, once to twice a day. Wait at least 15 to 30 minutes before adding other active products. In the case of retinols, retinyls, and retinals, wait at least 30 and preferably 45 minutes to allow the active ingredient to convert to retinoic acid within your skin.
DCX:
This is an eye treatment product with soy. It is not an exfoliate. Should be applied to clean skin, once or twice a day. Apply after acids and cleansers, before copper and other treatments. Wait 10 minutes to allow it to absorb. Then apply other products.
DMAE:
Can be used after acids and cleansing. Formulation type can dictate placement. Liquids, gels and serums can be applied before CP serums, lotions and creams. Lotion and cream DMAE should be applied after CP serums and creams. Wait 10 minutes to allow product to absorb.
Product Application by Type
This is a rough guide for product application, based on type/absorbency. This is for products that are not pH dependent, nor limited by activity type. The thickness of a product, dictates its placement. You cannot apply a thin product (like a liquid) over a thick product (like a cream) and expect it to absorb well. The cream can be a barrier to the thinner product.
-Cleanser
-Toner (pH-adjusting product in a liquid, watery form)
-Exfoliant (AHA or BHA, usually requires a wait time)
-Serum (Copper Serum, treatment Serums, DMAE thicker products)
-Gel (DMAE, Green Cream, Differin)
-Oils (Emu, Jojoba, Almond, etc)
-Creams
-Sunscreen
-Foundations
~Who in the world am I? Ah, that's the great puzzle~ Lewis Carroll, Alice in Wonderland
Blogs & Forums
