Sunday, February 12th, 2012

By John, Skincare Contributor

John describes himself as eccentric–you might find him having a conversation with himself or making “A Beautiful Mind”-like movements while doing so. He’s a stickler for accuracy, so you might find him correcting one thing or another! His goal is to answer questions and provide unbiased, meaningful, and insightful information.

At 21, he is an aspiring dermatologist and will return to school next fall to get those plans moving. John enjoys singing, playing piano, hitting volleyballs, playing video games, and chatting with friends. Some day, he’d love to try more adventurous activities, like skydiving and mountain climbing! Check out his blog, The Triple Helix Liaison!

The Skin Saga: Breaking Blemish

Currently, I have very oily, acne-prone, mildly sensitive skin that occasionally flakes and feels dehydrated in certain areas, like around the nose, mouth, and eyes.  I hope to one day have very pale, perfectly-formed, diamond-hard skin that will occasionally shimmer and radiate when exposed to sunlight!  This post will chronicle the stages of acne and explain how and what ingredients treat those stages.

Formation

A combination of factors including irregular polarization of the keratinocytes, excess sebum production from heightened androgen activity, and inflammation of the hair follicle lining, contribute to the formation of comedones, either as blackheads or whiteheads.  The ingredients that block or inhibit this step include the following:

  • Topical retinoids (tretinoin, adapalene, tazarotene): Topical retinoids function by reducing the positive and negative polarities of keratinocytes, which will allow for more even and normalized natural exfoliation. They do so by decreasing the levels of transglutaminase, an enzyme that cross-links the trans-membrane proteins present on keratinocyte surfaces.

Recommendations: Besides the brand-name and generic prescription treatments such as Retin-A, Differin, and Tazorac that are available from your doctor, the Peter Thomas Roth Retinol Fusion PM ($65.00), which allegedly contains 1.5% retinol, a precursor of tretinoin that is roughly 20 times weaker, is a fantastic option and I can personally attest that it provides significant results without much irritation. Note that “weaker” only refers to the ratio of retinol that undergoes esterification to become retinal and ultimately tretinoin. The word has nothing to do with the molecule itself because the skin cannot use retinol, only tretinoin.

  • Oral retinoids and contraceptives (Accutane, Ortho TriCyclen, Estrostep, and Yaz): Oral retinoids and contraceptives function by reducing sebaceous gland activity. Less sebum means lesser chances of clogs or plugs forming. This may be surprising but retinoids are actually types of hormones because there exist various receptors (RARs and RXRs) throughout the body that are activated by the presence of such chemicals. So while they are distinct, oral retinoids and contraceptives do have overlapping characteristics. Oral contraceptives function by reducing the amount of circulating androgens; they stimulate the production of sex hormone-binding globulin, which inactive testosterone.

Fun fact: Ever wonder why many women experience acne once they reach menopause? It’s because their estrogen levels plummet, which means they can no longer hide the effects of the androgens still present (at now comparatively higher levels). Estrogens exhibit anti-inflammatory properties by decreasing neutrophil chemotaxis (meaning they inhibit and slow down the immune system), while androgens do the opposite. I guess that explains why men love to fight!

  • Hydroxy acids (Glycolic, salicylic): This family of ingredients was already discussed in detail during my last post; they will only be covered briefly here. They function by loosening follicular impactions and inducing exfoliation.

Recommendations: Paula’s Choice makes excellent salicylic and glycolic leave-on products with varying degrees of concentration that employ different vehicular bases for corresponding different skin types. Alpha Hydrox makes several good ones as well. They are just less cosmetically elegant in my opinion.

  • Regarding cleansers with hydroxy acids: Most hydroxy acids require a certain pH range to function properly, which is determined by the acid’s pKa and molecular electronegativity. Now, when pH = pKa that signifies that equal amounts of the free acid and salt form are present in the solution (50/50). Only the free acid form will allow for meaningful exfoliation. Now, even if a cleanser is in an appropriate pH range, which many are not, it  still won’t function optimally because the pH of water is seven. The pKa of glycolic acid is 3.83; salicylic acid’s is 2.97. When you emulsify your cleanser with water and spread it onto your face, the pH will undoubtedly increase. By how much? It depends on how much water you use and if your cleanser is a buffered solution. You will be getting suboptimal or nonexistent treatment for your condition. Cleansers only stay on your face for what, thirty seconds? However, if you are currently using cleanser with a member of the hydroxy acid family in it, continue to use if you enjoy it, but I would advise against purchasing one expecting to see major results.

Learn more about the infection, inflammation, and eruption stages! 

Infection

These keratinocyte plugs (blackheads and whiteheads) and the underlying sebum are enticing meals for the bacteria (P. Acne) that’s present throughout the skin. They will amass at these sites in obscene numbers.  The ingredients that block or inhibit this step include the following:

  • Benzoyl peroxide:  Due to its weak oxygen-oxygen bond, benzoyl peroxide eliminates bacteria by generating reactive oxygen species (ROS). Note that long-term use of this ingredient will age the skin prematurely because of the ROS, which are free radicals.
    • Recommendations: Once again, Paula’s Choice has two benzoyl peroxide products (2.5% and 5%) that are excellent. Dan from Acne.org ($32.03) also makes an elegant gel formulation that is inexpensive and effective! Now, unlike with hydroxy acids cleansers, those with benzoyl peroxide are not pH dependent and can be quite effective at preventing infection, because they help eliminate any surface bacteria. However, cleansers with benzoyl peroxide won’t penetrate deeply enough to address any existing acne.
  • Topical antibiotics (clindamycin, erythromycin): These exhibit antibacterial and anti-inflammatory properties as they reduce the levels of free fatty acids produced by P. Acnes. Because these targeted antibiotics can produce resistant strains of bacteria, they can and should be combined with benzoyl peroxide to enhance efficacy since the latter generates ROS, which destroy non-specifically.  These are prescription medications and need to be prescribed by your doctor or dermatologist to ensure that they are appropriate for your skin.
  • Oral antibiotics (tetracyclines, macrolides): These function similarly as their topical counterparts because they target bioactive lipids generated from free arachidonic acid (AA) and act as various cyclooxygenase inhibitors, both of which plays an important role in the prostaglandin and leukotriene pathways. They’re like stronger versions of salicylic acid.
  • Sulfur and sodium sulfacetamide: The former functions by interacting with the cysteine content of keratinocytes, which will allow for the formation of hydrogen sulfide, which leads to the breakdown of keratin. The latter acts as a substrate blocker for para-aminobenzoic acid (PABA), which P. Acnes needs for growth and proliferation.
    • Recommendations: ProActiv makes a good sulfur mask that also contains anti-inflammatories. Products containing sodium sulfacetamide are typically available by prescription only.

Inflammation

Once the bacteria begin to feed at these keratinocyte plugs, they will release pro-inflammatory byproducts that can induce the expression of Toll-like receptors (TLRs), which are proteins that regulate aspects of the skin’s immune response. This will lead to increased redness and swelling; the physical manifestations at this stage are characterized as papules and pustules.  The ingredients that block or inhibit this step include the following:

  • Salicylic acid: In addition to its other benefits for acne, salicylic acid is also anti-inflammatory because it inhibits several AA cascades, like the ones described above, that induce inflammation.
  • Topical corticosteroids: These function by inhibiting the expression of several genes that code for inflammatory molecules such as cytokines, while inducing expression of anti-inflammatory ones such as MAPK phsophatase-1. However, this family of ingredients should be reserved for intense and very severe inflammatory conditions because while corticosteroids do inhibit inflammation, their mechanisms of action interfere with other cellular signaling that manifest with significant side effects such as skin atrophy, more acne, and lasting hyperpigmentation.
    • Recommendations: Although there are several OTC products with corticosteroids (hydrocortisone), I’d advise against using them because of the numerous side effects. Please see your doctor if you are thinking about using this group of ingredients.

Eruption

If left unchecked, these sites will become so highly inflamed that the hair follicle will rupture, releasing its contents into the dermis and allowing for further bacterial proliferation. Ever wonder how blemishes, more specifically cysts at this stage, get so large as to encompass areas the size of dimes? This is how.

At this point, although many of the enumerated ingredients can be used, the fastest way to get rid of cysts is to have them drained with a lancet by a qualified professional such a dermatologist or esthetician.

Some key points to remember:

  1. Only salicylic acid, benzoyl peroxide, and corticosteroids can actually treat inflammatory acne that’s already visible on the skin. All other treatments are designed to prevent future outbreaks.
  2. Acne is an INFLAMMATORY condition, which means additional inflammation is never a good thing. I recently had a reader ask me how long she should expect the “purging” process to last after switching to a new skin care product. With a few exceptions, acne should never get worse before it gets better, meaning that you shouldn’t be breaking out significantly more after using a new product. If you are, discontinue use of the product and find out what is causing your reaction. Worst case scenario: you have to search for a product with a different active ingredient to ameliorate your condition. As you can see, there are many!
  3. These steps are not clearly demarcated. For example the transitions from step 1 to step 2 to step 3 cannot be detected by the naked eye. Therefore, just because an ingredient is only paired with a single step doesn’t mean it can’t be used for the other ones.
  4. 4. Your skin is constantly going through the exfoliation process so you shouldn’t rely on a singular approach to combat your acne.  For example, if you only have blackheads and whiteheads, you’ll know that you don’t need benzoyl peroxide. If you have severe cystic acne and your doctor only prescribes clindamycin, and not benzoyl peroxide or a topical retinoid, you can ask why not. It’s all about making YOU feel more comfortable and secure in WHAT and WHY you are applying something to your skin.

Feel free to comment on anything! Maybe I got something wrong, or you would like to add something to what I said about hydroxy acids. Whatever it is, know in advance that it will be greatly appreciated! Also, if you would like to nominate a topic for my next post, let me know comments!

Sources


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64 thoughts on “The Skin Saga: Breaking Blemish

  1. Chelsea

    Have you ever tried the Oil Cleansing Method? Instead of cleanser, use olive oil and castor oil. Here’s the link I used, http://simplemom.net/oil-cleansing-method/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+simplemom+%28Simple+Mom%29&utm_content=Google+Reader
    But it’s made my skin a lot clearer and brighter and if I do get a zit, it’s not nearly as red or inflamed as it used to be.

    • annie

      I had a horrible experience with the oil cleansing method and I regret even trying it. I broke out in horrible cystic-like acne and I am just lucky that I was able to get rid of the spots without serious scarring. Obviously this method works foe some, but I have had much better luck with a routine much like John’s (I have been a PC devotee, minus the oil cleansing experiment, for going on 7-8 years now).

    • Yes I have, and it was a complete disaster. The idea that oil will “wash” the oils off your face is ridiculous to me, someone with very oily skin. And I know that it wouldn’t make my skin more clear or bright.

      Thanks for commenting!

  2. Cynthia

    John, there are so many skincare bloggers out there who tell us to buy this or that, but they do not tell us why – or more likely, they themselves don’t know why – except that it works for them. I love your more scientific approach to skincare!!!

    • Thanks Cynthia that means a lot! That’s my whole intention of writing these articles. I’m glad you learned something from this.

      Thanks for writing.

  3. Grace

    Thanks so much for the post! It was very much helpful and I thorougly enjoyed it. I will be looking forward to your next post :) Btw, will you be doing posts about acne only or other skin conditions also? Because I would love to learn about keratosis pilaris or rosacea, etc

    • Hi Grace, first of all, thanks for taking the time to comment! It really means a lot! And of course I can post on other skin conditions too. My next post will just focus on two ingredients, vitamins A and C. But who knows what I’ll write about next. Any suggestions on what you’d like to see? If I don’t post it on here, I’ll post it on my blog, or email you with an answer.

    • Irene

      It’d be awesome to learn more about rosacea or keratosis pilaris, as I’ve suffered both!

  4. Lucia

    John everything you post I read with so much attention, thank you so much for the time you put into these articles.

    I believe in another post I explained to you that I’d been using Paula’s Choice BHA 2% gel, and that I wasn’t particularly impressed with the results – you then recommended I use one of her AHA products, which I am going to order this week. My first question is, when during the week should I use these?/How should I alternate them? As well as breaking out, which I use benzoyl to try and combat, I have persistent white heads and black heads, which I hoped the BHA gel would tackle, but it hasn’t really done much.

    My routine: cleansing with clinque (until it runs out, then I’ll switch to Paula), follwed by a Paula’s choice toner, followed by BHA, then benzoyl peroxide on my blemishes, followed by moisturiser.

    Another point I wanted to raise was, I’ve been on the Yasmin contraceptive pill for 7 weeks now and I stopped taking my oxytetracyclin tablets at the same time, 7 weeks ago; my skin got really bad, and I still haven’t seen a significant improvement on the yasmin pill. Would you recommend I keep taking the oxytet AND the yasmin pill?

    I really value your opinion and all your comments.

    • Hi Lucia,

      What I meant by alternating, is to use the BHA during the day and the AHA at nighttime. Or you can alternat the BHA and AHA on alternate nights, if you don’t like how BHA feels under makeup. I hope the clarifies stuff. Also, for your present blackheads, salicylic acid won’t really remove them, especially if they’re persistent and stuck there haha! Its more geared for preventing future ones. To get them, you’ll want to extract them yourselves with a comedone removing tool or see a dermatologist/esthetician to remove them.

      As to the YAS and OXY question… I really hesitate to give you any advice since these are drugs and I’m not a medical professional yet. I can tell you theoretically what they’re supposed to do, but I don’t know if there will be any drug interactions, or combination side effects. Since you got these with a prescription (obviously), I strongly suggest you ask your doctor. Sorry! I mean YAS and OXY target completely different aspects of acne formation and its corresponding biology derivatives, but yeah, it wouldn’t be ethical for me to give advice on drug-related interactions! :(

      Thanks for commenting!

      • mumtaza

        What is the best black head removal tool you’ve come across? Thanks!

        • I’ve personally never used one before. I was given the chance to get a facial and my esthetician removed all of mine! Lucky me right? It was well worth it since I had literally hundreds on my face. Sorry, can’t be more use in this department. All I can tell you is that the tool looked like a long metal rod, with a tiny circle at one end.

  5. Lily

    Hi John, I really appreciate the amount of thought and detail you put into this post. About sulfur: I thought that it’s a skin irritant? At least that’s what Paula Begoun says! (Look for “sulfur”) And what does pKa refer to?

    • Thanks Lily! Well, I love Paula… but I don’t always agree with her. I mean anything can be a skin irritant. L-ascorbic acid, or vitamin C, is a notorious skin irritant, but you don’t see her complaining about that.

      So yes, sulfur can definitely irritate the skin, but it has a demonstrated and documented benefit for the skin, unlike essential oils. In the case of the latter, I do agree with Paula about that because they risk pointless irritation, while providing no topical benefit. But I digress.

      Sulfur is certainly an alternative to things like benzoyl peroxide. I hope that helped and thanks for commenting!

  6. Saffy

    I absolutely love your posts John, they’re so informative and helpful. I started using some of the PC products listed in your previous post, and my skin looks *so* much better. Thanks for taking the time to write these articles!

  7. Liz

    Dear John,

    Thank you for this wonderful, meticulous post! I LOVE this.

    I think it could be worthwhile to mention side effects of oral tetracyclines.

    - Although tetracyclines may kill bacteria in the skin, they also can make the skin exceedingly photosensitive during the time that they’re taken. Tetracyclines will photooxidize when exposed to sunlight (270-320 nm wavelength) and generate reactive intermediates in the skin. In fact, patients who take tetracyclines are encouraged to wear protective clothing and avoid sunlight.

    - Since tetracyclines are broad-spectrum antibiotics, superinfections are common, especially in patients who take them for more than 2 weeks. One of the potential complications, Clostridium difficile overgrowth, can be fatal.

    - A woman who is pregnant or could become pregnant shouldn’t take tetracyclines because they discolor the teeth and bones if taken during pregnancy or by children under 12. Furthermore, if the drug gets incorporated into fat, it can be toxic to the liver, especially during pregnancy.

    - Some patients who take tetracyclines suffer acute GI distress.

    I thought I would throw that information out there, since there are places where it’s possible to get antibiotics without getting a doctor’s warnings, or even the opinion of a lowly medical student like me.

    Thank you!
    A fellow skincare fanatic

    • K

      I think it’s important to clarify on why tetracycline should not be taken during pregnancy; naming just the discoloration effect may give expectant mothers undue trust in the safe use of this drug during their pregnancy. Tetracycline is known as a calcium chelator, meaning that it can bind to and therefore interfere with the biologic activity of calcium. This means that fetal exposure to tetracycline can negatively impact the formation of teeth and bones. While it certainly can cause a discoloration of the teeth this is a purely cosmetic issue, and not a legitimate medical issue. In case you are interested in some further info, the FDA classifies drugs based on their known or potential effects on a fetus. Tetracycline is a class D drug (the classes are A, B, C, D, and X), which refers to any drug that is known to carry the risk of aversive effects on a fetus from both controlled human and animal studies, and the use of such drugs are recommended during pregnancy only if the potential benefit to the mother outweighs the risk to the fetus.

      • Thanks K! Clearly you know what you’re talking about. Like I said for Liz, there’s just no space for me to list side effects for all the drugs and treatments mentioned. My goal was to broaden the readers prespective on what options are available and why they are useful. Should one want further instructions, he’d have to see a doctor for them anyways, at least in most countries. Thanks for commenting!

      • Liz

        I definitely did not mean to leave out the biggie. Thank you!

    • Hi Liz,

      Thanks for this fantastic addition to my post! I didn’t address any side effects for prescription drugs because I assumed that you’ll need to ask a doctor for them, and he/she would inform the patient about the risks. But yeah there are places where you can get them without a prescription. But if I listed the side effects for everything I mentioned in this post… well this would be five thousand million words long haha! Okay guess that makes it a billion.

      Anyways, I’m always happy to read your responses. Keep it up and thanks for commenting!

      • Liz

        Thanks, John!

        I definitely agree that listing side effects for everything would be pretty excessive, haha! This is already a hugely informative article. I just commented on the tetracyclines because, to me, their adverse effects are more severe than those for any other treatment on the list. Hopefully my comment is moot for the majority of readers (i.e. they will get meds through a doctor)!

        Again, completely awesome article!

        P.S. Apply to UT Southwestern :-)

  8. Melody

    Thanks for this informative post! I’m a bit confused about their not usually being a purging period for most products. I thought it was commonly held that when you start retin-a, for example, your skin will probably get worse before it gets better. At least that’s what happened to me. Retinoids are the only products I ever heard to expect that with, though. In any case, I would love to see a post on acne scarring, specifically what causes a scar and what products can help the scars fade the most quickly.

    • Hi Melody,

      Not to nit-pick, but I said “with a few exceptions…” haha! Yes tretinoin has been known to cause the purging effect because it irritates the skin so much. As you know now from reading this article, inflammation is not a good thing for acne. And since tretinoin treats and prevents future breakouts, the existing ones have to disappear first. I hope that clarified some things!

      And I already have a scars post planned for my blog, so yeah, thanks for the suggestion!

      • Melody

        Oh, I see. Thanks for clearing that up for me. It’s just that sometimes I guess I pick up random pieces of information about acne treatment and then I can’t remember if I learned something from a legitimate source or if I’ve just heard it a lot. I’ll definitely be checking out your blog!

  9. Ashley C

    I recently started using Paula’s skin care after reading you post and doing some research on my own. I’m really loving the results! My acne is slowly starting to go away and any new flares stay very small and go quickly as well.

    • Sounds great Ashley! I love hearing that you do your own research, but despite how “smart” and “informed” some people might think I am, I’m just another person who did my own research. Rock on!

  10. Rosanna

    If you live in Canada, NeoStrata has amazing Glycolic Acid products and they are NOT cleansers.
    I recommend their “Smoothing Creams” which come in three levels of glycolic concentration(1-6%, 2-8%, 3-10%). Always remember to let your skin get used to it by gradually building up frequency of applications!

    I’m looking for a good BHA or salicylic acid cream (I found two by Dermalogica and it’s sister CleanStart) at the moment. Any suggestions anyone? I live in Canada and not able to buy things online. Thanks in advance!

    • Steph

      I love Neostrata, too!

    • Kat

      I’d love to know the answer to this too! While I can order stuff online, I hate the shipping costs and the customs that Canadians tend to be subject to.

      And I’ll look into NeoStrata!

    • Thanks for the suggestion! Neostrata is also famous for their use of polyhydroxy acids like Lactobionic acid, which is a whole other discussion. But thank you for the suggestions!

      I wasn’t aware that Paula’s Choice wasn’t available to Canadian people. I’m sorry, I wouldn’t know haha! Thanks for commenting.

      • Rosanna

        It’s strange but NeoStrata in Canada is like an entirely different line than the the products on the US website. So weird!
        They don’t offer the same products either even though the smoothing cream was shown on the Dr. OZ show!
        NeoStrata is avaliable in lots of retailers in Canada (London Drugs & Shoppers to name a few)as well as two websites: well. ca & londondrugs. com.
        Just FYI for anyone interested.

      • Kat

        We can get Paula’s Choice, but we either have to order from the website – with more shipping than Americans – or try to eBay it.

        And it annoys me so much how some companies have so many more products in America vs Canada, we get a little screwed over. /end rant lol

  11. Sophie

    Hi John,

    Thank you for writing this very informative article!

    Like Melody, I’d love to know how to get rid of acne scars. Do you know if Paula’s Choice has any specific products against scarring? I’ve heard so much about this brand and I’m stopping by a counter next week so I’d love to try some PC products.

    • You’re welcome Sophie!

      As to your question about acne scars, it depends what your scars are. If it’s hyperpigmentation, things like hydroquinone and glycolic acid can help. If they’re physical scars like ice-pick ones, depending on how deep they are… things like vitamins A and C can help by rebuilding collagen. However, only if they are very shallow. Deep scars can only be treated by a dermatologist; depending on the type of scar they’d inject a filler under the scar, or cut it out and follow with laser therapy to stimulate the production of new tissue.

      Hope that helped and I will be doing a post about scarring on my blog. Thanks for writing!

  12. Shannon

    Thank you so much for posting this! It is so detailed and helpful unlike anything else I’ve been able to find on the internet. :)

  13. An

    Thank you for the detailed post.

    Looking forward to the next post about vitamins, particularly vitamin C.

  14. Frances

    Hi John! Great article. I find it slightly horrifying to read about the stages of breakouts (am very squeamish), but fascinating nonetheless.

    Do you have an opinion on the Clarisonic? I’m thinking of getting one, and would love to hear what you have to say about it. Cheers!

  15. mumtaza

    Sweet post! I related to something you said in there: my doctor prescribed me an antibiotic ointment for a bug bite a while back, later I had an infected it on my face. I put two and two together, said “vaya con dios”, and put the prescription ointment on the pimple, and it cleared that sucker up. Later I asked her to refill the prescription just so I could have that option around. Also salicylic acid and benzoyl peroxide give my face chemical burns in basically any concentration. Why is that? What do you think of tea tree oil?

    • Thanks! Benzoyl peroxide creates free radicals, so that’s known to irritate the skin. As for salicylic acid, the acidic aspect of it could be irritating as well. Or you could be mildly allergic to it, I can’t know. If you’re sensitive to salicylic acid, which also has an inflammatory action to it, then you’d most likely be sensitive to glycolic acid too.

      Consider looking into lactic acid, which is a less irritating version of glycolic acid.

      Tea tree oil… well it’s not as documented as benzoyl peroxide, but some studies suggest that it as a mild antibacterial action to it. You can try it out, but be cautious about it.

  16. Ada

    Clay/mud mask once to twice a week (depending if using makeup daily) will help unclog pores. A hydrating overnight once a week to keep moisture locked in and reduce oil production. Also, using clarisonic every night to remove the dirt (especially after makeup or sunscreen) is definitely essential.

    Moreover, water intake and sleeping early is life changing ! Making sure you have regular bowel activity to detox is also important.

    • Ada

      To add, using AHA and BHA product once a week!

      I found these regular routine helps much more than taking medications and putting different creams on (unless for spot treatment).

      • Hi Ada,

        What you’re saying is true, at least the areas of nutrition and sleeping earlier. However, those aspects can’t be quantified and therefore will vary extremely from person to person. Topical treatments are essential however. Millions of people throughout history and I are walking examples of that fact. I wouldn’t be too quick to dismiss everything and suggest the “homeopathic” route.

        Clay masks can help absorb facial oil and dislodge small blackheads. And the Clarisonic doesn’t remove “dirt” from the face. It’s a form of manual exfoliation that removes dead skin cells, and it certainly won’t remove existing blackheads.

        The routine that you’re saying may work for you, but that means unfortunately, very little because there’s no specific evidence behind them.

        Anyways thanks for commenting.

  17. Tara

    Excellent article!! As a nurse, I really appreciate the medical/scientific expertise you bring to the table!! Please keep up the good work!

  18. Kayvid

    Do you know if any of these react with each other. As in, after a Salicylic toner, is it okay to put on a sulfur based spot treatment? Or a BP based spot treatment?

    • Yes several of them shouldn’t be used concurrently. However, instead of me just listing everything, to save time why don’t you ask me what combination you plan to use, and I’ll let you know from there. :)

    • Benzoyl peroxide will cancel the effect of tretinoids (tretinoin, isotretinoin, alitretinoin), second generation of retinoids (etretinate, acitretin) and third generation of retinoids (azarotene, bexarotene) if they are used at the same time. Adapalene is the only one that can be used with benzoyl peroxide without a problem (it is a third generation retinoin) and all the retinol forms:retinol, retinal (retinilaldehyde), retinyl acetate, retinyl palmitate.
      The best way to use BP in combination with retinoids is to apply BP in the morning and retinoids in the evening.
      Actually, retinoinds should always be applied at night because the active ingredient is very instable in presence of light.

      • Yes Corina is correct, adapalene is immune to benzoyl peroxide because of the addition of aromatic rings that replace the weak double bonds in the carbon chain. All other forms of retinoids shouldn’t be used to BP. However, that doesn’t answer Kayvid’s question. I guess that’s more my fault than yours haha! Salicylic acid can be used with benzoyl peroxide and and sulfur.

  19. monica

    Great post! Very detailed and contains so much valuable info. I love your posts!!!

  20. Hi John,
    The article is very good, but is also very general. Before running to pharmacy to buy all this ingredients (they are great and they do what you say) I think we should know more then general facts. For example, you didn’t mention any interaction between this ingredients (they are important and you know that) and you didn’t explain how can these ingredients be integrated in a routine (they are all irritants, the skin needs time to accept them or not!).
    The most side effects from these ingredients are because of incorrect use and maybe you will write about the importance of applying sunscreens everyday, not using skin irritants, etc.
    I think you are doing a very good work with these articles :)

    • Hi again Corina.

      Thank you for your compliment. And I realize that this article is quite general. However, it has to be. Like I said to Liz and other above, there’s no way I can explain every substance in detail because that would take a novella at least.

      Not to mention that most people can’t just “run to the pharmacy” and grab these products without a prescription. In order to get one, they’d have to see a doctor and he/she will get the appropriate information and warnings across. For OTC products, if readers have questions, I’m here to answer them, which is why I asked Kayvid what specific combination he/she has in mind.

      And you’re incorrect that most side effects come from “incorrect use.” They are listed as side effects because they’ve been well-demonstrated in laboratory and clinical trials. And you can be damn sure that these substances are used correctly in those trials and settings.

      I appreciate your criticism, but I’d like for you to know that they are unfounded and unfortunately not applicable.

      But thanks again! I’m sure some of the readers who didn’t comment had similar concerns as you. So know they know xD.

      • Hi John,
        I didn’t mean to criticize and I understand now that my words does not apply in a country like US where you need to have a serious conversation with a dermatologist (and not only that) before taking Accutane for example in compparasy with my country where I see more women using drugs without knowing the smallest thing about them.
        In Romania, most of the side effects experienced by women who use all kind of ingredients (retinoids, BP, hydroquinone, etc) are exacerbated by the incorrect use like: lack of using sunscreens during the day, incorrect association of ingredients, lack of proper moisturizing (and when I say moisturize I don’t mean emolients).
        I have spend the last year trying to make Romanian women understand that running to the pharmacy and applying all sorts of ingredients on the skin is not the answer and to teach them how to understand the skin and the problems that come along with it.
        I am sorry again if I have been misunderstood, I do appreciate your work more then you think.
        I will check on your blog for an email address and I will send you an email if you don’t mind.

        • Hi again!

          It’s completely understandable. And I meant no offense when I said that you criticized me since positive criticism is essential. :)

          And of course you can email me whenever about whatever; I respond to everyone as you can tell haha. I look forward to reading your thoughts if and when you do decide to send over an email.

          Thanks for commenting back. Keep up the fantastic work in Romania!

  21. Amy

    Hey John,

    As another said, I love your scientific and analytic approach! I’d love to see an article about acne scars in the future. There are so many “whitening,” “lightening” products out there and so many different recommendations for how to treat acne scars, it’s hard to know what actually works, and what’s actually for treating scars and not just whitening the skin in general.

    • Thank you Amy. I’ll put that request on my to-do list. Many people have requested this so it’ll be a priority. Thanks for writing!