It’s often said that our skin is our largest organ. Our brain or liver are the largest solid organs by mass (which one comes out on top will vary from person to person), our gut is the longest, and our lungs are the largest by surface area. But our skin is large, noticeable, and has a big impact on the rest of our health.

The sun is one of the main damaging factors for our skin; assorted toxins are also a major threat for many people, and once the skin barrier gets broken, it’s a field-day for bacteria.

So, what can we do about it?

Tretinoin: the skin’s rejuvenator

Tretinoin is also called retinoic acid, not to be mistaken for retinol, although they are both retinoids. Tretinoin is much stronger.

As for what it’s stronger at:

It’s usually prescribed for the treatment of sun-damage, acne, and wrinkles. Paradoxically, it works by inflaming the skin (and then making it better, and having done so, keeping it better).

In few words: it encourages your skin to speed up its life cycle, which means that cells die and are replaced sooner, which means the average age of skin cells will be considerably younger at any given time.

This is the same principle as we see at work when it comes to cellular apoptosis and autophagy in general, and specifically the same idea as we discussed when talking about senolytics, compounds that kill aging cells:

Fisetin: The Anti-Aging Assassin

About that paradoxical inflammation…

❝The topical use of tretinoin as an antiacne agent began almost a half century ago. Since that time it has been successfully used to treat comedonal and inflammatory acne.

Over the intervening years, the beneficial effects of tretinoin have grown from an understanding of its potent cornedolytie-related properties to an evolving appreciation of its antiinflammatory actions.

…

The topical use of clindamycin and tretinoin as a combination treatment modality that includes antibacterial, comedolytic, and antiinflammatoiy properties has proven to be a very effective therapy for treating the various stages of acne

…

It is now becoming increasingly clear that there may be good reasons for these observations.❞

~ Drs. Schmidt & Gans, lightly edited here for brevity

Read in full: Tretinoin: A Review of Its Anti-inflammatory Properties in the Treatment of Acne

Against damage by the sun

The older we get, the more likely sun damage is a problem than acne. And in the case of tretinoin,

❝In several well-controlled clinical trials, the proportion of patients showing improvement was significantly higher with 0.01 or 0.05% tretinoin cream than with placebo for criteria such as global assessment, fine and coarse wrinkling, pigmentation and roughness.

Improvements in the overall severity of photodamage were also significantly greater with tretinoin than with placebo.

…

Several placebo-controlled clinical studies have demonstrated that topical tretinoin has significant efficacy in the treatment of photodamaged skin. Improvements in subjective global assessment scores were recorded in:

49–100% of patients using once-daily 0.01% tretinoin,

68–100% of patients using 0.05% tretinoin, and

0–44% of patients using placebo.❞

~ Drs. Wagstaff & Noble

…which is quite compelling.

Read in full: Tretinoin: A Review of its Pharmacological Properties and Clinical Efficacy in the Topical Treatment of Photodamaged Skin

This is very well-established by now; here’s an old paper from when the mechanism of action was unknown (here in the current day, 17 mechanisms of action have been identified; beyond the scope of this article as we only have so much room, but it’s nice to see science building on science):

❝Tretinoin cream has been used extensively to reverse the changes of photoaging. It is the first topical therapy to undergo controlled clinical testing and proved to be efficacious. These results have been substantiated with photography, histopathologie examination, and skin surface replicas.

…

Tretinoin cream has an excellent safety record; a local cutaneous hypervitaminosis A reaction is the only common problem.❞

~ Dr. Goldfarb et al.

Read in full: Topical tretinoin therapy: Its use in photoaged skin

Is it safe?

For most people, when used as directed*, yes. However, it’s likely to irritate your skin at first, and that’s normal. If this persists more than a few weeks, or seems unduly severe, then you might want to stop and talk to your doctor again.

*See also: Scarring following inappropriate use of 0.05% tretinoin gel

(in the case of a young woman who used it 4x daily instead of 1x daily)

Want to try some?

Tretinoin is prescription-only, so speak with your doctor/pharmacist about that. Alternatively, retinol is the strongest natural alternative that works on the same principles; here’s an example product on Amazon 😎

Take care!

Psyllium is the powder of the husk of the seed of the plant Plantago ovata.

It can be taken as a supplement, and/or used in cooking.

What’s special about it?

It is fibrous, and the fiber is largely soluble fiber. It’s a “bulk-forming laxative”, which means that (dosed correctly) it is good against both constipation (because it’s a laxative) and diarrhea (because it’s bulk-forming).

See also, because this is Research Review Monday and we provide papers for everything:

Fiber supplements and clinically proven health benefits: How to recognize and recommend an effective fiber therapy

In other words, it will tend things towards being a 3 or 4 on the Bristol Stool Scale ← _{^{this is not pretty, but it is informative.}}

Before the bowels

Because of how it increases the viscosity of substances it finds itself in, psyllium slows stomach-emptying, and thus improves feelings of satiety.

Here’s a study in which taking psyllium before breakfast and lunch resulted in increased satiety between meals, and reduction in food-related cravings:

Satiety effects of psyllium in healthy volunteers

Prebiotic benefits

We can’t digest psyllium, but our gut bacteria can—somewhat! Because they can only digest some of the psyllium fibers, that means the rest will have the stool-softening effect, while we also get the usual in-gut benefits from prebiotic fiber first too:

The Effect of Psyllium Husk on Intestinal Microbiota in Constipated Patients and Healthy Controls

Cholesterol-binding

Psyllium can bind to cholesterol during the digestive process. Why only “can”? Well, if you don’t consume cholesterol (for example, if you are vegan), then there won’t be cholesterol in the digestive tract to bind to (yes, we do need some cholesterol to live, but like most animals, we can synthesize it ourselves).

What this cholesterol-binding action means is that the dietary cholesterol thus bound cannot enter the bloodstream, and is simply excreted instead:

Plantago consumption significantly reduces total cholesterol and low-density lipoprotein cholesterol in adults: A systematic review and meta-analysis

Heart health beyond cholesterol

Psyllium supplementation can also help lower high blood pressure but does not significantly lower already-healthy blood pressure, so it can be particularly good for keeping things in safe ranges:

❝Given the overarching benefits and lack of reported side effects, particularly for hypertensive patients, health care providers and clinicians should consider the use of psyllium supplementation for the treatment or abatement of hypertension, or hypertensive symptoms.❞

~ Dr. Mina Salek et al.

Read in full: The effect of psyllium supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials _{^{← you can see the concrete numbers here}}

Is it safe?

Psyllium is first and foremost a foodstuff, and is considered very safe unless you have an allergy (which is rare, but possible).

However, it is still recommended to start at a low dose and work up, because anything that changes your gut microbiota, even if it changes it for the better, will be easiest if done slowly (or else, you will hear about it from your gut).

Want to try some?

We don’t sell it, but here for your convenience is an example product on Amazon

Enjoy!