Do please give a full report!!! I’ll wait before I place my next spf order incase you found a winner.
Because my skin is so sensitive, I rarely try new things, but I can be convinced 
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spinout company partners with L’Oreal on research to reprogramme ageing cells
A biotech company which specialises in reprogramming ageing cells has partnered with L’Oréal Groupe, the beauty industry leader.
L’Oréal recently announced the new Research Agreement Partnership with University of Exeter spinout company SENISCA yesterday.
The deal was announced as the company unveiled the L’Oréal Longevity Integrative Ecosystem, which it said “merges L’Oréal’s advanced research with an external ecosystem of leading partners in longevity science”.
In a press release, the company yesterday said the agreement with SENISCA would “harness their expertise and proprietary technology to reprogram aged ‘senescent’ cells, which behave differently to young, healthy cells and are a crucial aspect of longevity”.
SENISCA is developing new approaches that reverse how our cells start to decline as we age. As we get older, our tissues accumulate cells that are senescent – meaning they are alive, but do not grow or function as they should. These old cells lose the ability to correctly regulate the output of their genes, and can produce chemicals which promote inflammation, which is known to be implicated in many diseases. The ageing process also affects the way these cells send messages to organs, a process which is also linked to diseases of ageing. SENISCA has identified a novel component of the cellular ageing response and is harnessing this proprietary know-how to reprogram aged cells.
Professor Lorna Harries, of the University of Exeter, who is founder and Chief Scientific Officer of SENISCA, said: “I’m incredibly excited that almost 20 years of my team’s research has resulted in this partnership with L’Oreal, a global leader in skin health and beauty products. This partnership recognises our potential to create new and better ways to slow the ageing process of our cells, which could have benefits for our skin health. Outside of this partnership, we’re also exploring how we can apply our technology to reduce the negative impacts of age-related diseases such as lung disease.”
Company Website:
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I think it’s a really positive sign to see such a large skincare and cosmetics company go all in on this. This is the future.
In search of methods to improve the youthful appearance of skin they are likely to find unique methods of addressing, among other things, AGEs, and this can have deeper ramifications for longevity.
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Looking at someone like PD Mangan, who is nearing 70 and has really good skin for his age, it’s clearly possible to slow down signs of skin aging. There are also videos of people over 90 years old who have youthful skin; and then there’s that old Connie Chung video when she visited Yuzurihara, Japan and saw people there with excellent skin well into their 90s (you can look it up on YouTube).
It’s worth also looking at the other end of the spectrum, of people who look old for their age, and ask why that is. One example is Bert Jansen, who supposedly holds a record for living the longest following a heart transplant (in his case, he got it back 1984 when he was 17):
He was 57 when that video was taken, but looks much older. It could be due to inflammation from the transplant, or the medicines he takes… or, perhaps the heart donor was a little older than he was back in 1984 (articles say the donor was a “young adult”, which typically means age 18 to 25 or so). If that’s the case, then perhaps it shows that youthful-looking skin is a reflection of more youthful organs, in general. Perhaps aging organs secrete inflammatory compounds – DNA fragments, cytokines, etc. – that impact the skin.
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New Nature Aging paper titled “Skin Health and Biological Aging” (authors include several leading aging researchers):
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Do you have the full paper?
I do, but there is some risk involved in sharing it. Here is the conclusion of the paper:
Aging lies at a crossroads where numerous interlinked factors and physiological outcomes converge. In the context of skin aging, this complexity is magnified due to the skin’s role as both a barrier and an active participant in systemic health. While valuable progress has been made in identifying the hallmarks of aging, translating this knowledge into effective interventions remains a formidable challenge. Developing precise biomarkers and advanced skin models will be essential to bridge the gap between understanding and intervention. Only a holistic and truly geroscientific approach to understand aging, not focused on its individual hallmarks, will allow this field to advance.
The paper doesn’t really say much new, but summarizes some findings from the literature.
Skincare strategies, the science of facial aging, and cosmetic-intervention guidance | Tanuj Nakra, M.D. & Suzan Obagi, M.D.
We discuss:
- Tanuj’s and Suzan’s training and expertise, and the evolving field of aesthetic medicine [4:00];
- The biology of the aging face [10:45];
- Why facial fat atrophies with age while body fat tends to accumulate [17:00];
- How chronic stress accelerates facial aging [20:30];
- The evolutionary biology of beauty, and how modern lifestyle, culture, and medicine interact with these ancient aesthetic instincts [25:30];
- How social media and influencers have rapidly shifted aesthetic trends toward exaggerated features and unrealistic beauty standards [36:45];
- The ethical challenges, financial incentives, and social pressures shaping modern aesthetic medicine [42:00];
- The concerning trend of teenagers seeking cosmetic enhancements: the ethical and cultural impact of early beauty pressure [51:45];
- Protecting the skin: UV damage and sunscreen recommendations [58:15];
- Strategies for minimizing skin aging: retinoids, vitamin C, and evidence-based application methods [1:09:00];
- Effective daily skincare routine: cleansing, antioxidants, retinoids, moisturization, and more [1:18:45];
- The playbook for managing acne [1:31:00];
- The 4 changes of aging and the complexities of aesthetic consultations including the anatomical, psychological, and ethical factors physicians must navigate [1:39:00];
- The 5 R’s of rejuvenation [1:50:15];
- A facial aging analysis and cosmetic strategy using Peter’s face as a real-time case study [1:53:00];
- The decision-making process between fat grafting and dermal fillers for facial rejuvenation [1:56:30];
- How self-image, eye aesthetics, and fleeting photos drive the desire for cosmetic enhancement [2:01:45];
- Advice for wrinkles, causes of dark circles under the eyes, and the importance of facial symmetry [2:05:45];
- Considerations that shape clinical decision making around fat grafting and other procedures to address the eye area [2:11:00];
- The evolution of facial cosmetic surgery techniques, the serious risks involved, and how physician skill and procedure selection greatly impact outcomes [2:21:30];
- How patients can make informed and safe choices when selecting a cosmetic surgeon [2:27:15];
- A comparison of ablative versus non-ablative skin resurfacing treatments, laser vs. peels, and more [2:38:45];
- How treatments are chosen and customized based on patient-specific factors [2:48:00];
- The lifelong human desire to align physical appearance with self-identity [2:52:45]; and
- More.
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I have listened with interest to the skincare routines suggested, but some suggestions kind of clash with the suggestions of some other specialists I’m following (medical dermatologists who also practice facial surgery).
For example, retinol and its use in the summer. They (the guests in the podcast) do not exclude it. But a common opinion is that it may cause a dishomogeneous complexion, even if applied only at night, with the exclusion of some Korean products using a milder form of retinol.
Vitamin C as L-ascorbic acid: They do not cite the optimal concentration or range of concentrations, whereas the current opinion is that 10% to 20% is the range that has been studied in the literature.
They suggest applying vitamin C (or retinol? Or both?) even around the eyes, whereas AFAIK around the eyes, a specific eye contours product is suggested to shield the fragile skin from irritation subsequent to the application of other products.
Anyone with more opinions about the above?
I’m no expert on skincare, but I’ll chime in anyway
FWIW,
I’ve been seeing very good derms and plastic surgeons for over 20 years for Botox etc, and there has never been one to suggest that I don’t use tretinoin during the summer. Caroline Hirons, a respected UK skin guru influencer says the same thing. However, to your point, they all say it’s imperative to use spf 50 all the time.
I also listened to that podcast and wish they had not shared the other recommended products behind the Attia paywall… (in the show notes). I’d love to find a quality less pricey vit C to consider.
I’ve heard some people mention that while they think vit C is good, they don’t think it deserves anywhere near the hype it receives. I don’t know what to think about this and am curious about everyone’s thoughts on the matter. Those two docs, while they are good, sell a vit C, so I also take their opinion on that one with grain of salt. I have a body vit C but was not planning to repurchase it, but now I’m wondering?
There are also many types of vit C to choose from. Over the last year or so, I’ve been using a combo product from Elevai (it’s great and my skin loves it, but I’m considering stopping because I think I’m way overpaying for bells and whistles that most likely don’t work … stem cells and exosomes). Prior to that I used Trinny London Vit C… supposedly a good form and one of the strongest available. My sensitive delicate skin tolerated it very well.
It’s my impression from anything I’ve learned is that we should use things under our eye IF we can get our skin to tolerate it. Often a specific eye product is needed because they often include fewer actives, which makes it easier to do so (and profitable for the companies :). I personally just use the products for my face there and buffer it with lotion if/when I ever need it. I will put things on my lid only near my brow because things do migrate. On that note, I don’t take them all the way to my lower lash line for the same reason. She was the first one I’ve heard recommending to put tret on one’s eyelid, and I imagine she is correct in doing so, but ?
Until I could tolerate tret under my eyes (not daily), I would use tret on my face and a strong retinol under my eyes.
I think @LaraPo is one of our skincare gurus here, so I’ll tag her.
EDIT: also, I had been only using zinc spf until discovering Japanese spf a couple of years ago (the only chemical that my eyes can tolerate). I had learned from Caroline Hirons and a chemist “lab muffin” that chemical spf actually offers greater protection than zinc, which is the only reason I sought out a chemical. They both said nuh uh, and only use zinc… but I’m wondering if this is just because they are only speaking about the US available chemicals. What they mentioned are not in the non US SPFs … thoughts anyone ??
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I knew you’d have something valuable to add!
That reminds me that they said they feel zinc is better becasue it lasts longer than chemicals. I used to hear that as well, but in the past couple of years, I kept hearing that chemical is superior (not that zinc isn’t also great). Do you feel physical spf offers longer protection than chemical, @LaraPo ?
I’ll see if I can find the lab muffin video that mentions chemical providing better protection. I’d be happy to never use chemical again (my dry skin loves zinc and enjoys the tint for an all in one moisture, spf, and makeup solution)
EDIT:
I found a written blurb by her instead of a video
Here are the highlights.
So yes, the guests on Attia were only addressing US spf. And she also confirms what I had been hearing and that non US spf do offer great protection. She goes into this with charts/graphs and references in one of her videos
YOU NEED TO REAPPLY CHEMICAL SUNSCREENS IF THEY’RE EXPOSED TO SUN, BUT NOT PHYSICAL SUNSCREENS (SORT OF TRUE)
This myth is based on the idea that chemical sunscreens aren’t photostable, which means the molecules break down after absorbing too much UV and need to be replaced. But these days a lot of chemical sunscreens are photostable. The most photounstable combination is avobenzone and octinoxate, so it’s a good idea to reapply sunscreens with that combination frequently.
But you should really be reapplying ALL sunscreens, even without sun exposure. The main reason why you need to reapply sunscreen is that sunscreen shifts around and off your skin throughout the day, esepcially if you’re active.
However, studies on daily sunscreen use found significant benefits even with once a day application and with regular activity
DIFFERENCES BETWEEN CHEMICAL AND PHYSICAL SUNSCREENS
The big differences between them that you should consider are:
PROTECTION LEVEL
SPF 50+ is pretty common with both types of sunscreen, but broad spectrum protection (that includes protection against longer wavelengths of UVA) is where there’s a difference.
Organic sunscreens give higher, photostable protection from UVA if you use newer filters like Tinosorbs S and M, and Uvinul A Plus (not yet available in the US). The more common avobenzone gives really high UVA protection, but it breaks down in UV so you have to be diligent about reapplication (although some formulas stabilise avobenzone so it breaks down slower, and you should diligently reapply sunscreen anyway if you’re spending a lot of time in the sun)
EDIT
This is where she mentions the limits of one rating where zinc has limitations … it’s the UVApf
There’s been some new developments in zinc oxide technology, where essentially you can use different shapes of zinc oxide particles that absorb UV better. But still, with zinc oxide alone, you can only usually get about SPF 60 and UVAPF 20 before it turns into white chalk paste, but chemical sunscreens can go up to SPF 100+ and UVAPFs of over 60 (in regions where those ratings are allowed, anyway).
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I have no idea! Per Dr Stanford, chemicals are absorbed by skin and get into bloodstream, and minerals are not. So you choose what you think works better for you.
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…plus, I think I remember well, Peter Attia’s guests told ‘and wear a hat’. I think i’m goign to consult the AAD guidelines on retinoids and sun protection, probably like everyone seems to point out if a strategy of sun protection is very diligent, then it’s all right, but I noticed that very diligent means applying and re-applying all the day long, plus wearing a wide-brimmed hat…
In my case, it’s a sure thing I’ll never be so strict. The data collected by the AI seems to agree on strict sun protection and preferably the use of retinol based product only by night. It may be a good compromise.
Based on current dermatological literature and guidelines, topical retinoids (retinol, retinaldehyde, retinoic acid [tretinoin], adapalene, tazarotene) do increase skin sensitivity to UV radiation and can cause issues during summer months. Here’s a detailed breakdown of the evidence and actionable advice:
Key Mechanisms of Increased Sensitivity & Potential Issues
-
Enhanced UV Sensitivity & Photodamage Risk:
- Thinning of Stratum Corneum: Retinoids accelerate cellular turnover, leading to a temporary thinning of the outermost protective layer (stratum corneum), reducing its natural UV barrier function.
- Increased Photosensitizing Metabolites: Retinoid metabolism generates compounds that can act as photosensitizers, absorbing UV energy and generating free radicals.
- Upregulation of Matrix Metalloproteinases (MMPs): Retinoids (and UV independently) increase MMPs, enzymes that break down collagen and elastin. UV exposure while using retinoids significantly amplifies this collagen-degrading effect, counteracting retinoids’ long-term anti-aging benefits and increasing photodamage risk.
- Evidence: Studies consistently show increased susceptibility to sunburn (erythema) and UV-induced DNA damage (thymine dimers) in retinoid-treated skin. (Kang et al., J Invest Dermatol, 2005; Fisher et al., Arch Dermatol, 1997).
-
Increased Irritation & Compromised Barrier:
- Initial “Retinization”: Starting retinoids or increasing strength often causes dryness, redness, peeling, and stinging – common side effects collectively called “retinization.” This process compromises the skin barrier.
- Summer Exacerbators: Heat, humidity, sweat, sun exposure, chlorine (pools), and salt water can further irritate retinoid-compromised skin, worsening redness, stinging, and peeling.
- Evidence: Clinical trials and dermatological reviews consistently report higher rates of irritation during retinoid use, which environmental factors like sun and heat can trigger or worsen. (Szymański et al., J Am Acad Dermatol, 2019; Mukherjee et al., Drugs, 2006).
-
Risk of Hyperpigmentation:
- Post-Inflammatory Hyperpigmentation (PIH): Irritation or inflammation caused by retinoids (especially if combined with sun exposure) can trigger PIH in individuals with darker skin tones (Fitzpatrick III-VI).
- Evidence: PIH is a well-documented potential side effect of retinoid irritation, and UV exposure is a major trigger for melanocyte activation. (Davis & Callender, J Clin Aesthet Dermatol, 2010).
Actionable Strategies for Summer Use (Based on Literature & Guidelines)
-
Sunscreen is NON-NEGOTIABLE:
- SPF 30+ Broad Spectrum: Use daily, even on cloudy days. Look for “Broad Spectrum” (UVA/UVB protection).
- High UVA Protection: Choose sunscreens with high UVA-PF (e.g., containing Zinc Oxide, Titanium Dioxide, Avobenzone stabilized with Octocrylene, Tinosorb S/M, Mexoryl SX/XL).
- Amount & Reapplication: Apply liberally (1/4 tsp for face) 15-20 mins before sun exposure. Reapply every 2 hours, and immediately after swimming or heavy sweating. Don’t rely solely on makeup SPF.
- Evidence: Sunscreen is universally recommended as the primary protective measure when using retinoids. (American Academy of Dermatology [AAD] Guidelines; Sbidian et al., Br J Dermatol, 2016).
-
Adjust Application Timing & Frequency:
- Apply ONLY at Night: UV degrades retinoids, reducing efficacy and potentially increasing photosensitizing byproducts. Nighttime application minimizes UV interaction.
- Reduce Frequency: If experiencing significant irritation or spending extended time outdoors, reduce application (e.g., switch from nightly to every other night or 2-3 times/week).
- “Sandwich” Method: Apply moisturizer first, wait 20 mins, then apply retinoid, then more moisturizer to buffer irritation.
- Evidence: Nighttime application is standard practice. Reducing frequency buffers irritation. (Szymański et al., J Am Acad Dermatol, 2019; AAD).
-
Prioritize Barrier Repair & Hydration:
- Gentle Cleanser: Use non-foaming, fragrance-free, hydrating cleansers.
- Soothing Moisturizers: Look for ingredients like Ceramides, Niacinamide, Panthenol (B5), Glycerin, Hyaluronic Acid, Centella Asiatica. Apply liberally, especially after washing.
- Evidence: Maintaining skin barrier function reduces retinoid irritation and TEWL (transepidermal water loss). (Draelos, J Drugs Dermatol, 2013).
-
Avoid Additional Irritants & Exfoliants:
- Pause Harsh Products: Temporarily avoid physical scrubs, AHAs (glycolic/lactic acid), BHAs (salicylic acid), high-strength Vitamin C (L-ascorbic acid), benzoyl peroxide (if not prescribed together), and facial waxing on retinoid-treated areas.
- Evidence: Combining irritants significantly increases barrier disruption and inflammation risk. (Lyons et al., Dermatol Ther, 2019).
-
Sun Protection Beyond Sunscreen:
- Seek Shade: Especially during peak UV hours (10 am - 4 pm).
- Protective Clothing: Wide-brimmed hats, UV-protective clothing, sunglasses.
- Evidence: Physical barriers provide highly effective UV protection. (AAD).
-
Consider Lower-Strength or Alternative Retinoids:
- Retinol/Renaldehyde: Generally better tolerated than prescription tretinoin. May be a good summer option for those struggling.
- Adapalene 0.1% (OTC): Less irritating than tretinoin and more photostable. Often better tolerated in summer.
- Evidence: Adapalene demonstrates less irritation potential and greater photostability compared to tretinoin. (Nyirady et al., Cutis, 2001). Retinol requires conversion and is generally milder.
-
Listen to Your Skin & Consult a Dermatologist:
- If irritation is severe (painful burning, cracking, intense redness), stop retinoids and focus on barrier repair until skin calms down.
- A dermatologist can help tailor your regimen, suggest alternative anti-aging ingredients (like Bakuchiol, peptides), or recommend prescription strategies.
Conclusion
Yes, topical retinoids do increase skin sensitivity to UV radiation and can cause irritation, photodamage, and hyperpigmentation during summer. However, they do not need to be discontinued with proper precautions. Strict, diligent sun protection (high SPF broad spectrum, reapplied liberally) is the absolute cornerstone of safe summer retinoid use. Adjusting application (night only, reduced frequency), prioritizing barrier repair, and avoiding other irritants are also crucial. If significant irritation occurs, switching to a gentler retinoid (like adapalene or lower-dose retinol) or temporarily reducing/pausing use is advisable. Always consult a dermatologist for personalized advice.
Key References
- Szymański, L., et al. (2019). Retinoids: active molecules influencing skin structure formation in cosmetic and dermatological treatments. J Am Acad Dermatol, 81(4), AB265. (Practical guidelines & mechanisms).
- Kang, S., et al. (2005). Topical tretinoin enhances topical 5-fluorouracil clearance of actinic keratoses. J Invest Dermatol, 125(3), 549-555. (Mechanism: UV damage & MMPs).
- Fisher, G. J., et al. (1997). Molecular basis of sun-induced premature skin ageing and retinoid antagonism. Arch Dermatol, 133(5), 539-543. (Mechanism: UV + Retinoids = ↑MMPs).
- American Academy of Dermatology (AAD) Guidelines: Position statements and patient resources on retinoid use and sun protection. (aad.org).
- Sbidian, E., et al. (2016). Efficacy and safety of oral alitretinoin in severe chronic hand eczema: a meta-analysis. Br J Dermatol, 174(2), 269-276. (Highlights importance of sun protection with retinoids).
- Nyirady, J., et al. (2001). The stability of tretinoin in tretinoin gel microsphere 0.1%. Cutis, 68(4 Suppl), 17-20. (Compares irritation/photostability of adapalene vs tretinoin).
- Davis, E. C., & Callender, V. D. (2010). Postinflammatory hyperpigmentation: a review of the epidemiology, clinical features, and treatment options in skin of color. J Clin Aesthet Dermatol, 3(7), 20–31. (PIH risk with irritation/UV).
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You might already know this, but also the reason to use it at night is that most retinoid products are made inactive if exposed to sunlight. I have seen some exceptions, but those are not the norm.
I’ll use a body retinol during the day, but only on parts that I cover with clothing (I don’t do this often enough simply because I’m too lazy!).
I am starting to believe that the guests of the Peter Attia podcast should have been perhaps more prudent in their suggestions. A product that tends to sensitize the skin to UV rays, even if it is applied only at night, and that requires rigorous protection from the sun… Maybe is a seasonal product only.
Here people go to the beach in the summer and on the shoreline the UV radiation just about doubles from sea surface reflection.
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Oh, that reminds me, and I don’t recall them saying this… I’ve always heard that using vit c during the day can enhance the effectiveness of your spf.
I don’t remember exactly what they said (I have a memory like a sieve), but if they didn’t, to your point, they should have strongly emphasized that if you are not going to be really careful about your sun protection, then you should definitely not be using retinoids. If one is living your lifestyle, than I, too, would consider making it seasonal. I make it a point not to get sun
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Some of the newer UVA/B screens available in Europe and elsewhere are pretty unlikely to go systemic given their relatively large molecular size.
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Actually, I’ve abandoned the beach lifestyle; my skin does not tolerate solar radiation any longer, for unknown reasons, I only tolerate radiation if the weather is cloudy or at sunrise/sunset. Or if I can start getting a tan from early March, very gradually. This does not worry me, since after a life of sun exposure, my skin should probably take a rest, I won’t force my luck in that the damage might have been far worse.
However, in the Summer and especially around the solstice the radiation can be very strong and to me it’s impossible to wear a hat or stay in the shadow or apply sun protection several times a day. So, no retinol sounds like the best option, then I’ll use retinol only at night from september/October. Here the specialists usually advise its use only by night, but then they might be conservative, better safe than sorry…
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