Skin ages faster when damaged mitochondria pile up, and mitophagy, the cleanup of those faulty mitochondria, is supported by cutting oxidative stress and by urolithin A, which only about 40% of people can make on their own.

• What to do: Lower the oxidative stress inside your cells: eat fewer processed foods, limit chronic UV exposure, sleep enough, manage stress, strength train and keep vitamin D and omega 3 levels in check.
• Why it matters: Mitochondria produce the energy your skin needs, and they get injured by aging, insulin resistance, inflammation, sun damage and poor diet. Damaged ones take up space and make cells work worse.
• How to apply it: Add polyphenols such as EGCG from green tea and cocoa flavanols, plus carotenoids such as astaxanthin and beta carotene, which help reduce the oxidative burden that mitophagy depends on.
• Tools: Urolithin A, available as oral and topical products, and a supplement whose dose has been studied. Choose products with third party testing that shows an adequate amount.
• Metrics: Urolithin A has been linked in research to lower CRP, a marker of inflammation.
• Risks: Taking too many carotenoids can turn the skin orange, as in the tan maxing trend.
• Exceptions: Foods like walnuts and pomegranate give urolithin A only if your gut bacteria can convert them, and antibiotics can wipe out those bacteria.

Sun protection accounts for about 80% of what you can influence in skin aging, so sunscreen by day, vitamin C in the morning and a retinoid at night beat any supplement, while acne, eczema and psoriasis often trace back to gut health, insulin and hormones.

• What to do: Wear sunscreen daily, use vitamin C in the morning and a retinoid at night, wash and moisturize, and add strength training, omega 3s and a whole food diet low in sugar and dairy.
• Why it matters: UV light is the number one extrinsic driver of skin aging, while sugar, insulin resistance, gut imbalance and falling estrogen add inflammation that breaks down collagen and worsens acne and psoriasis.
• How to apply it: Try a 2 to 3 week elimination of gluten, dairy, sugar and processed food for inflammatory skin problems, ask your doctor to check insulin, thyroid, vitamin D and gut health, and choose mineral sunscreen if chemical filters worry you.
• Metrics: Optimal fasting insulin is under 5, an omega 3 index above 8% is the goal, and the dermatologist says 65% of more than half a million Function Health members have high insulin.
• Tools: Retinol or tretinoin, topical vitamin C, niacinamide, copper peptides, urolithin A (Timeline Mitopure), omega 3s, collagen peptides and Function Health lab tests.
• Risks: Retinoids are not safe in pregnancy, lemon juice irritates skin, chemical sunscreens absorb more into the blood, and exosomes and injectable GHK Cu lack enough safety data.
• Exceptions: Gluten avoidance is strongest for people with positive gluten antibodies, and beef tallow is an overrated skincare trend.

Skin loses its bounce after menopause because the deep layer (collagen, elastin) and the surface layer (lipids and water) decline at the same time, so a collagen cream alone fails and you need a three part plan: support, stimulate and protect.

• What to do: Use a targeted serum with peptides or growth factors plus a moisturizer with glycerin, use a retinoid at night, exfoliate on a separate night and wear zinc oxide sunscreen daily.
• Why it matters: UV creates oxidative stress that switches on enzymes that break down collagen, so ignoring sunscreen cancels everything else you stimulate.
• How to apply it: Morning: serum, moisturizer, sunscreen. Night: serum, retinoid on select nights, moisturizer. Give the flash mask its own night and leave it on for 10 to 15 minutes.
• Metrics: Retinol comes in 0.3, 0.5 and 1.0 and the right one is the strength you tolerate consistently. A PDRN cream showed a 45% improvement in barrier strength after one application. Glycolic acid 15% with lactic acid 3% in the mask. Zinc oxide 11% in the sunscreen.
• Tools: Dr. Reju-All PDRN copper peptide serum and cream, Paula's Choice multi-peptide booster, SkinMedica TNS Advanced+, Clarins Double Serum, SkinCeuticals Retinol, Dr. Idriss Major Fade Flash Mask, ISDIN Eryfotona Actinica.
• Risks: Collagen in a cream will not rebuild facial collagen, and exfoliating every night on dry postmenopausal skin can irritate it.
• Exceptions: Growth factor serums can pill, so use them at night, and sleeping in the flash mask only suits skin that is not sensitive.

Most "copper uglies" are not a copper allergy at all: pure l-ascorbic acid and benzoyl peroxide can chemically cancel out copper peptides, and an already irritated skin barrier reacts to almost any new active, copper included.

• What to do: Use active vitamin C (l-ascorbic acid) in the morning and copper peptides at night; ester forms like tetrahexyldecyl ascorbate can be layered together safely.
• Why it matters: A canceled-out ingredient just wastes money, but burning, peeling, or new breakouts signal a barrier problem that copper is usually not the true cause of.
• How to apply it: Introduce a copper peptide alone for one night before adding it to a full routine, and give an irritated barrier two to three weeks of a bare-bones routine first.
• Risks: Injectable GHKCU is not FDA approved, is often labeled for research use only, and independent testing has found contaminants like arsenic, mold, or bacteria in some products.
• Exceptions: Azelaic acid has no solid evidence of canceling out copper peptides and can typically be used alongside them without separating by time of day.

Makeup sits worse on skin after 40 because oil production drops, skin renews roughly every 40 days instead of every 28, and fine lines catch more foundation, so the fix is working on texture the night before and layering hydration the morning of the event.

• What to do: the night before, use a lip peel exfoliant on the under eye area too, apply an overnight mask, and seal with moisturizer; the morning of, mist skin with water, rose water, and glycerin before any other product.
• Why it matters: past 40, skin takes about 40 days to renew instead of 28, so dead cells build up on the surface and make foundation look dull and settle into fine lines.
• How to apply it: pick your moisturizer based on the makeup you are wearing, an emollient one with shea butter or mineral oil and wax for full coverage looks, and a lightweight, fast absorbing gel for everyday makeup.
• Tools: under eye creams with lacto PDRN or with ceramides and panthenol depending on how dry you are, a daily hydrating serum, and a sunscreen filter that will not leave a white cast.
• Exceptions: if you have perioral dermatitis or an oilier nose, apply a thinner layer of serum and moisturizer in those areas so you do not overload them.

Perioral dermatitis usually clears within one to two weeks of stripping the skincare routine down to nothing, and the two things most likely to turn a mild flare into a stubborn one are topical steroids and thick, occlusive creams.

• What to do: Stop moisturizer, serums, and sunscreen on the affected area, and switch to a plain, non-exfoliating cleanser applied by hand, not a washcloth, for at least one to two weeks.
• Why it matters: Treating the bumps like acne with salicylic acid or benzoyl peroxide, or masking them with a topical steroid, tends to trigger a rebound cycle where the rash returns worse each time.
• How to apply it: Watch for tiny, uniform pink bumps that spare a thin border around the lips; if flares keep returning despite the reset, a dermatologist can prescribe a low-dose oral antibiotic, such as doxycycline, for its anti-inflammatory effect.
• Risks: Stopping a topical steroid abruptly can cause a rebound flare, and even mineral sunscreens can aggravate the rash because of fragrances or preservatives in the formula.

Every laser in the country targets only red, brown, or water, so before paying thousands for a package the question is which of the three it treats, and for pigment and mild redness a well built routine often does the same job for the price of a dinner.

• What to do: Identify your lane: brown (spots), red (redness and vessels), or water (texture). For brown, use actives that block pigment production such as arbutin, licorice root, niacinamide, and tranexamic acid, plus chemical exfoliation at night. For an inflamed barrier, cut the routine to one or two calming products.
• Why it matters: Skincare is like the diet and the laser is like liposuction: without a supporting routine the laser result is lost. For texture a laser does in three months what skincare takes two or three years to match, and no cream collapses a broken capillary.
• How to apply it: Do not exfoliate in the morning, keep glycolic acids for the night. With melasma, choose a picosecond laser and expect more than 10 to 12 sessions. Hydroquinone is used two months on and two months off. With retinoids, prioritize consistency over intensity.
• Tools: kojic acid, arbutin, licorice root, niacinamide, tranexamic acid, Major Fade Hyper Serum, Murad dark spot serum, SkinCeuticals CE Ferulic, Paula's Choice C15, Flash Mask, hydroquinone, Skin Rocks HPR, Shani Darden Retinol Reform, Combat Cream, Aveeno Calm + Restore, Left Un-Red Reducer Serum; VBeam, Fraxel 1927 and 1550, picosecond lasers, microneedling with and without radiofrequency, erbium and CO2 lasers.
• Exceptions: with an inflamed barrier do not laser, repair first; with broken capillaries skincare does not work and you need the VBeam; with active acne do not laser texture until breakouts are controlled.
• Risks: hydroquinone is not for long term use; retinoid prescriptions are poorly tolerated if overused; a product sold as a topical 10 percent azelaic acid was not what the label said.

Three different things are sold as azelaic acid: the free suspension from the classic studies, the ionized form at a higher pH, and the derivative potassium azeloyl diglycinate, which contains no azelaic acid at all. The ionized form that sparked the drama is safe and effective, according to a 2012 study.

• What to do: Identify which of the three forms you own; if it is the free suspension (The Ordinary or prescription), apply it to damp skin and wait a minute or two before your retinoid.
• Why it matters: One brand spent years selling a product marketed as 10% azelaic acid that was only the derivative, with no azelaic acid; the labeling, not the pH, was the real issue.
• How to apply it: Use it every night before tretinoin or retinol; the ionized form and the derivative need no waiting. Start the retinoid at just two nights per week.
• Metrics: The initial itch lasts the first 10 to 20 minutes and usually fades within 2 to 3 weeks; stubborn pigmentation needs 15% or higher.
• Exceptions: For redness or oily skin the derivative works well; for melasma use the 15% prescription; if a pharmacy formula fails, ask for a different manufacturer.