All cosmetic products have an expiration date and at one point they become rancid, have a change in their chemistry or lose their efficacy.

It is very important to avoid using contaminated products which can carry bacteria and cause many skin problems like: rashes, breakouts, dermatitis and infection, to name a few.

I get you, the excitement of a new discovery promising to be the holy grail of healthy, glowing skin is just too hard to ignore.

That’s the story of how most of us end up with an abundance of skincare products from which we only use a few and before we know it, the bathroom cabinet does not have space to fit one more q tip and yet we continue to pile up more skin goodies.

Getting rid of them is a different story though.  I am with you, it feels more like a slow torture. After paying your hard-earned money it makes you cringe just to think that all of it is going right into the garbage can.

But, when is time to toss away those skincare products before they can harm the skin?

As a rule of thumb, once opened most skincare products should be used within six months to a year because oxygen and bacterial exposure will increase the chance of contamination.

A good idea is to mark the product with a pen indicating the date it was opened, that way you don’t end up using the product long after it is still considered safe.

The FDA (Food and Drug Administration) whom regulates cometics in the U.S. does not require an expiration date on the product label. So, finding out when the expiration date is in cosmetic products sometimes is hard to tell.

Take a look at the full labeling guide on the FDA website for more detailed information.

Some products will clearly describe the expiration date on the label. Others may use phrases like : “best used before the end of”… or similar while many others will not indicate it.

There is also a graphic symbol known as “PAO” used by some Companies, which states for “Period After Opening” identifying the lifetime of the product once it has been opened.

Look for the number after the letter “M” on the label, it indicates the months that the product is safe and stable to be used after opening. For example: M12 (indicates that the product is good to use for 12 months after its opening date).

PAO graphic symbol indicates "period after opening" a product that the product is still safe to be used

In general, unopened skincare products have a useful life longer than opened products because they have not been exposed to bacteria. The life of an unopened product commonly lasts from one to three years depending on the product. A good phrase to go by is “when in doubt, toss it out”.

If you have had a product stored for a while and when you open it, it has a funky smell or an unusual texture, it’s time to get rid of it.

According to Oprah Magazine  in the article called “5 Skincare Products That Expire Faster Than You Think”, cosmetic Chemist Mort Westman says: “ If you’re unsure how old something is, the general rule is to toss anything that has significantly changed in color or odor, or separated, clumped, thickened or thinned.

One very important thing to keep in mind is that packaging can influence how the product decomposes. Jars for example, tend to get contaminated faster than other forms of packaging that don’t come in direct contact with oxygen and hand-dipping.



*** This is a general informational chart. Lifetime of products are determined by their chemical composition, packaging, storage and handling of the product.




To preserve the life of your products there are some golden rules that need to be followed:

  • Keep your products in a dark place away from sun light when possible.
  • Maintain the lids closed and tight to prevent oxygen exposure and preserve the active ingredients in the product. This is particularly important when the product contains antioxidants which are very sensitive to sun light and oxygen.
  • Use a spatula to swipe the product out of the container instead of your hands.
  • Don’t expose your products to high temperatures. This could change their chemical composition.
  • Throw away products if you have had an infection
  • Disinfect the product’s container or lid if you have dropped it on the floor, sink or other place that has a risk of bacterial contamination.


For more useful information on how to make your products last longer take a read at Paula Begoun’s list of “Do’s & Don’ts of making your products last” included in her article “When to Toss Out Beauty Products .


Always remember…

Fresh products mean better performance and therefore; better results.


Thank you very much for being here.

Until next time,

Dora Salazar

Medical Aesthetician

Founder of Zkin Fix Skincare


best face serum for aging skin


Finding the best face serum for aging skin can become a complicated task.

Zkin Fix was created to offer multiple skin solutions while  simplifying and optimizing your skin care, providing fast outstanding results.

As collagen production decreases volume is lost and shadows, lines and folds form. Normally, many products would be necessary to prevent, correct and rejuvenate the skin. But with Zkin Fix you will target the common signs of aging skin in one easy step. Visible changes are noticible very quickly and you will love the fact that it is simple to use and even easy to take along when you travel.

Video Transcription

  • We are all in the search of good products to look great

Yes, the modern world offers a dynamic lifestyle we want to stay active, feel great but look great too.

Products need to offer solutions and be effective.

  • What makes Zkin Fix different

It helps to optimize your skincare regimen in one step having the benefits of 5 anti-aging serums in 1.

It contains a high concentration of active ingredients considered necessary to support the building blocks for healthy skin

It offers the strength and efficacy of a clinical product in a safe, clean formulation

  • How did you get involved in skincare?

I come from a family with a lot of skin issues:

eczema, acne, dermatitis… and I have suffered them as well. I got frustrated looking for help with no answers. So, I decided to get deep into skin care to help myself and fell in love with the skin. It is fascinating what an incredible organ the skin is.

  • Special benefits of Zkin Fix Age Reversal Serum

It targets all the common signs of aging skin like:

Lines and wrinkles, dehydration, skin dullness, poor elasticity and uneven skin tone

It prevents, corrects and rejuvenates the skin

  • Where can I find Zkin Fix?

You can order it directly from my online store

And in the offices of skin professional partners

comparison between a serum and a cream

Is your bathroom cabinet full of serums or are you more of a cream fanatic?

I am sure that if you are like most people the answer will probably be “both.”

When it comes to skin care, decisions can be hard. Temptation is as strong as a cup of coffee on a Monday morning. You face magazines giving you the latest beauty buzz, social media bloggers tapping on their must haves and celebrities raving about their favorite skin care products. From exotic facial oil serums to lavishing creams, they all sound incredible and promise quick solutions to every skin problem.

To choose correctly it is important to step back and take a closer look at the pros and con of each product and see which one fits your individual needs best.

If you are looking to correct a skin issue or for intense nourishment, serums also known as “boosters”, will give you an in-depth form of treatment to achieve accurate results. They have a light consistency and are well known for being concentrated formulations aimed to target specific skin concerns such as: anti-aging, acne, rosacea, hyperpigmentation, flaccid skin, dehydration, dull skin etc.

For example, one of the most popular types of serum in the market is vitamin C because of its many skin benefits. It can help brighten up the skin, support collagen production improving elasticity and lightening up hyperpigmentation helping to even out skin tone.

The main purpose of serums is to deliver active ingredients deep into the skin. They have great absorption power and generally contain a higher concentration of active ingredients providing fast results, which is why they are a fantastic addition to any anti-aging or corrective skincare routine.

The best way to select the right serum is to first identify the skin concerns and then select a serum with specific ingredients to target those concerns. They often can be layered since they don’t feel greasy on the skin and penetrate rapidly.

The combination of active ingredients in serums normally does not allow the inclusion of an SPF.  Therefore, it is important to add a sunscreen to your day time skin care regimen.

Although, there is not a norm as to when is the right age to start using serums, early 30’s is a good age to begin a preventative skin program since the skin begins to experience some changes at that age. Mature skin likewise, can benefit from the use of serums to help restore and maintain better skin functioning and to combat the common signs of aging skin.

What is applied first, the serum or the cream?

Because of their light texture and ability of absorption, serums are applied first. Moisturizing creams second and if used separately from the cream, sunscreen should be applied last.


—If you are using several serums, begin layering them with the one that has the lightest texture. Always “from thin to thick”. This is a good way to remember the order of use.

What are facial creams?

Facial creams include a broad range of textures and purposes for the skin, from plain hydration to sun protection and everything in between.

Active ingredients can also be contained within the formulation, but they are generally present in lower concentrations when compared to serums.

Creams have a heavier consistency which implies the addition of more fillers, emulsifiers and occluding (sealing) ingredients, making the formulation less aggressive.

Gel-creams and lotions are frequently thought as creams, these have a lighter texture and are more suitable for combination and oily skin types while heavier creams are more appropriate for dry skin.

There are also day and night creams. Day time creams typically contain antioxidants to counteract the effects of free radical damage, accentuated with the exposure to environmental elements during day hours and many of them already have SPF protection included within the formula.

Night time creams on the other hand, are rich in regenerative ingredients like retinoids, growth factors or stem cells among others, to support the skin’s ability to repair itself. One common characteristic of creams is to occlude hydration within the skin to prevent trans epidermal water loss.

Should I use both, serum and cream?

Both products are good depending on the skin type.

Oily skin does not need as much moisturization as dry skin, since the skin produces sufficient sebum. Thus, a serum can be more than enough, of course not forgetting the addition of sun protection during day time.

Someone with dry skin though, might find that the serum alone does not provide enough moisture and will need the additional lipids that moisturizing creams provide.

Be aware to find a moisturizer that is compatible with your skin type. Avoid using heavy creams if you have acne prone skin. And if you have dry skin, stay away from products containing drying alcohols or other drying ingredients that can aggravate dehydration.

When selected correctly, both serum and cream, can complement each other very well. The serum, delivering active ingredients deep into the skin and the cream, sealing those ingredients in and maintaining normal moisturization levels.

Thank you very much for being here.

Until next time,

Dora Salazar

Medical Aesthetician

Founder of Zkin Fix Skincare


Retinoids are they good or bad

Many people live in a continuous love-hate relationship with retinoids.

They like its effects on the skin, especially long-term benefits but dislike the side effects that often come with its usage: irritation, redness, inflammation, peeling etc., especially at the beginning when the skin is acclimating to it.

However, it is an ingredient that has substantial scientific research to sustain claims of improving the overall physiology of the skin with a history that dates from the 1950’s initially acclaimed for the phenomenal effect that it had on acne patients.

Later, in the 1980’s it was revealed as the new gold standard for anti-aging for its capacity to work at a cellular level to improve skin functions and self-repairing abilities, improving lines and wrinkles and refining the skin texture for a more youthful appearance.

It is very important to first understand the different categories available in the market:

Retinoids are vitamin A compounds and derivatives of natural and synthetic origen and within them there are two main categories.

Prescription strength (retinoic acid, tretinoin, available in cream and gel formulations) and OTC formulas containing (retinol and various types of retinol derivatives often described as: Retinyl Acetate, Retinyl Linoleate, Retinyl Palmitate and Retinyl Proprionate; regularly found in many cosmetic products).

The two categories are often alleged to be similar, but the main difference is that retinol is eventually converted into retinoic acid. The skin uses vitamin A as retinoic acid, so the prescription strength formulas are readily available to be used by the skin.

On the other hand, Retinol is considered gentler on the skin but it takes longer time to reach the results of the prescription counterpart, since the skin has to convert it into retinoic acid, although it is still very effective if patience is not an issue to you.

Without further due, let’s take a closer look to some of the almost magical attributes of retinoids?

  • Encourages skin cell regeneration. This is a strong characteristic because it maintains skin normal functioning, thus preserving a more youthful performance.
  • Improves and supports normal skin tone helping to lighten hyperpigmentation from sun damage, post inflammatory and hormonal induced like melasma.
  • Stimulates the production of collagen and elastin
  • Minimizes the appearance of fine lines and wrinkles
  • With newer cells exposed and increased collagen and elastin production as well as hydration levels, the skin looks smoother and the appearance of pores is also improved.
  • Reduces and prevents the formation of blackheads, whiteheads (millias) and overall pore congestion.
  • Balances sebum production (skin natural humectant).


But just like everything else in life..

Things are not all white or all black. Retinoids also have their dark side and must be used with care to achieve  full benefits without causing any harm to the skin.

Here are some recommendations and important factors to consider to get the best use and results from retinoids:

  • It is not an ingredient that should be used if you are trying to become pregnant, if you are pregnant or if you are breastfeeding, in high doses it has been associated with birth defects.
  • A slow approach is better; this allows the skin to acclimate to it and minimize side effects, such as those mentioned earlier.
  • A small amount is enough to do the trick. A safer way to start is by using it every third night for a week or two, than every other night for a week and eventually every night or according to your physician recommendations. The ingredient is so effective that even when you use it a few times a week, you will still see results.
  • Apply it when the skin is fully dry to minimize risk of irritation
  • Keep it in a dark place to avoid the product from oxidizing and losing effect.
  • Do not mix with any exfoliating acids or other types of exfoliation. With that, I mean from products and also waxing, threading, sugaring, skin treatments like chemical peels or microdermabrasion etc. And if you still want to take a chance to do it, please go to a professional and let them know that you are using Retin-A. The skin will literally peel off and can leave a scar or result in post-inflammatory hyperpigmentation. If you are having a treatment done it is regularly recommended to suspend the use of Retin-A at least 4 to 7 days prior to the procedure depending on the treatment to avoid negative side effects.
  • Retinoic acid has also proven to improve the appearance of stretch marks, especially when they are in the initial state ( reddish color).


The standard recommendation of use for Retin-A is during your night time skincare routine. If you have dry skin, a good tip is to wait 20 minutes after the Retin-A application and apply a simple hydrating moisturizer, this will prevent excessive dryness.

Since the skin can become more sensitive and drier, I suggest that you include in your skincare routine other products containing ingredients to fortify your lipid barrier and increase hydration.

Some great options are: hyaluronic acid, panthenol, ceramides, lipids, niacinamide. Anti-inflammatory ingredients are also great to minimize redness and irritation, like: aloe, allantoin and bisabolol.


Because your skin becomes more sensitive to the sun when using retinoids, using a good formulated SUNSCREEN daily is crucial to prevent sun damage and to protect your new skin.


I like retinoids, the history is there. We know they work. I have been using them on and off for a long time and I find that it is an ingredient that if used with care you can get fantastic benefits from it.

In my case, I don’t mind being patient and for the sake of my skin, being so sensitive, I prefer to use retinol. I have tried Retin-A many times, but it has been too harsh for me, even the time- released formulations. My skin has its moments, and I normally must suspend its use when my skin begins to act up. 

I personally cannot tolerate it more than two to three times a week, but that is the perfect dosage for my skin. I see the difference and my skin does not become an angry mess. Your skin will be the judge as to how often is your magic formula.

If retinoids are in your list of favorite ingredients, I suggest you start using it at a lower strength and grow into a higher percentage considering your skin reactions, that will guide you to reach an adequate dosage and optimum result. Take into consideration though, that you must be persistent to achieve those results, using it sparingly just a few times a month is not enough to make a big difference.

Also, don’t feel discourage if you are not a retinoid person. There are many people that have tried it over and over and it simply is too aggressive for them to tolerate.

There are other options now in skincare far less invasive and with no side effects, like peptides or stem cells that work through cellular communication to encourage the skin to respond to specific functions like: collagen stimulation, improving lines and wrinkles, cell repair, skin firming etc. without inducing negative reactions or making the skin sensitive to the sun. That’s why I included them in Zkin Fix Age Reversal Serum. I find them to be very effective and safe with no risks or side effects involved.

I believe that it is not about using everything or every trend that comes out there. As a matter of fact, I think that well chosen ingredients do much more than too many ingredients which at the end, there is a big chance that are fillers and irritants that won’t do much to improve the skin.

Let your skin decide.

After all, your skin care is a journey of discovery. Experiment with care and enjoy all the steps.

Thank you very much for being here.

Until next time,

Dora Salazar

Medical Aesthetician

Founder of Zkin Fix Skincare