The Ingredients List series
Our Ingredients List series is way more than just a list of ingredients. It’s a set of articles that’ll dive into every active and filler used in skincare – whether you find them in Re-Dox or not – so you can better understand how, when and why they work, see through the myths about them, and create a routine that is effective for you.
TL;DR
Cis-resveratrol and trans-resveratrol are two naturally occurring forms of resveratrol, but only trans-resveratrol is able to activate SIRT1 and initiate DNA repair mechanisms. Trans-resveratrol is poorly bioavailable when taken orally and more studies support the topical route of trans-resveratrol as likely more superior for skin health. Topical trans-resveratrol serums require careful formulation (ideally with cyclodextrins) to increase its stability and bioavailability in the skin.
BECOME A STOCKIST: Trans-Resveratrol and Glutathione boosted in our 15% Vitamin C Day Serum for the prevention of pre-mature ageing.
Which form of resveratrol is best?
In our previous blog (part I), we showed that ageing was partly due to accumulated DNA damage and that resveratrol is a naturally occurring antioxidant which can repair DNA damage via activating the DNA-repair protein, SIRT1.How exactly does resveratrol do this?
Some proteins require a ‘key’ to activate and this is true for SIRT1. Resveratrol conveniently fits into the binding site of SIRT1, which then causes SIRT1 to become activated and initiate DNA repair mechanisms.
However, only one form of resveratrol can truly do this – the trans-resveratrol form.
Trans-resveratrol fits into the binding site of the SIRT1 protein which causes a conformation change of the protein leading to its activation.
Resveratrol can exist in two states (known as isomers) – trans and cis and both these forms can occur naturally. Studies show that trans-resveratrol is predominately found in freshly squeezed grape juice, while cis-resveratrol is largely found in red wine, likely as a result of fermentation.
The key difference between the trans and cis resveratrol is the conformation or shape of the molecule.
While trans-resveratrol appears as a linear or ‘straight’ molecule, cis-resveratrol is almost bent in half.
Does the shape of resveratrol matter?
Yes - only trans-resveratrol can ‘fit’ into the lock-and-key mechanism of SIRT1 to activate the protein. Cis-resveratrol is simply the wrong shape to conveniently fit into the SIRT1 binding site and because of this, we do not see the same level of SIRT1 activation.
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Choosing skincare with resveratrol
Now that we have established that trans-resveratrol is the ideal form for SIRT1 activation, this brings us to our next problem – the rapid isomerisation of resveratrol in solution (i.e. when formulated for skincare).
When in solution, trans-resveratrol rapidly changes shapes (or isomerises) to cis-resveratrol – making it less than ideal for the purpose of DNA repair and thus anti-ageing.
How to keep resveratrol from getting ‘bent out of shape’
Luckily, scientists have developed an answer using sugar groups called cyclodextrins.
You can think of cyclodextrins as sugar molecules with basketball hoop or bucket structure. This allows trans-resveratrol to neatly fit inside the basketball hoop and prevents it from bending into the cis-resveratrol form. This is termed the cyclodextrin-inclusion complex which stablishes trans-resveratrol and increases its bioavailability to the skin, when applied topically.
Trans-resveratrol cyclodextrin-inclusion complex
So far, we have established that trans-resveratrol is required to activate SIRT1 (for DNA repair) and it needs to be stablished in cyclodextrin-inclusion complexes.
But it begs the next question: what is the best way to take resveratrol for optimal skin health?
Oral vs topical resveratrol – which is ideal for skin health?
There isn’t a great deal of research directly comparing oral and topical formulations of resveratrol for improved skin health.
When it comes to resveratrol (and any other drug for that matter), the dose and the ‘contact time’ matters. This means that even at the correct dose, it needs to hang around long enough to have an effect. This is called a ‘half-life’ – the time it takes for resveratrol levels to reduce by half.
When taken orally, resveratrol is rapidly broken down by the liver and cleared from the body with a half-life of 2-4 hours and a bioavailability of less than 1%!
In other words, it doesn’t stay in the blood stream long enough or at high enough concentration to have a meaningful biological effect – at least for skin health.
Studies on oral resveratrol for skin health have conflicting outcomes and, in one study, there were no visual improvements.
Luckily, resveratrol is a fat-loving molecule which is great for skin penetration.
Resveratrol can easily pass through and accumulate in our skin where it can act directly on dermal fibroblasts (and other skin cells) for optimal skin health.
Most studies have used 0.25%-1% of topical resveratrol and have shown many positive outcomes, including protection from UV radiation and excessive oxidative stress.
Some studies even suggest topical resveratrol is more effective than oral resveratrol in preventing acute skin inflammation.
Summary
In summary, resveratrol is a potent active ingredient in the fight against pre-mature ageing and skin health, though sadly it is underutilised in the skincare world. Rather than merely another antioxidant, resveratrol acts as a bio-stimulator within cells to initiate DNA repair. Healthy cells have healthy DNA and resveratrol has the ability to help cells repair DNA. Trans-resveratrol is likely the most effective form, though it requires careful formulation to increase it’s stability and bioavailability in solution.
*Re-Dox offers stablised trans-resveratrol with cyclodextrin, boosted in the Nourishing Phenolic Day Serum for fight against pre-mature ageing.
