Skin aging and elasticity
Everything in the library studied for it, medical and holistic together. Within each kind, what was shown to help comes first, strongest evidence first. What was tested and not shown to help stays on the list.
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Medication
Fine wrinkles from sun damage
Shown to improve fine sun-related wrinkles modestly at tretinoin 0.02% or stronger, with 10% moderately improved against 3% on vehicle. Weaker strengths did not differ from placebo.
Compared with vehicle cream, with sun protection in both arms [7][8][9]
The numbers and sources
- How common
- Very common: more than 1 in 10 people.
- Effect
- In a Cochrane review, tretinoin cream at 0.02% or higher was superior to placebo for mild to severe photodamage of the face and forearms. Improvement on 0.05% cream at 24 weeks had a relative risk of 1.73 (95% CI 1.39 to 2.14). No effect was seen at 0.001% or 0.01%, and benefit and irritation both rose with strength [7]. A 2025 meta-analysis found tretinoin improved fine wrinkles over vehicle (MD 0.412, 95% CI 0.233 to 0.590) [8]. In the Renova 0.02% label trials, 60% on tretinoin improved at least minimally against 39% on vehicle, and 10% against 3% moderately, after 24 weeks [9].
- Population
- 8 tretinoin trials in a review of 30 [7]; 1,361 patients aged 29 to 76 in 8 trials, 16 weeks to 2 years [8]; 559 lightly pigmented adults in 4 trials [9].
- Sources
- [7], [8], [9]
- Caveats
- Losses to follow-up were high in most trials [7]. Only 2 of the 5 Renova trials on their own showed a benefit, and the label states the cream does not eliminate wrinkles or reverse photoaging. In 107 darkly pigmented adults, 29% improved on tretinoin against 43% on vehicle [9].
Collagen formation in sun-damaged skin
One small trial found tretinoin 0.1% raised new collagen I formation 80% in sun-damaged forearm skin over 10 to 12 months, against a 14% fall on vehicle.
Compared with vehicle cream [11]
The numbers and sources
- Effect
- Collagen I formation was 56% lower in sun-damaged skin than in sun-protected skin. Daily tretinoin 0.1% cream increased collagen I formation by 80%, against a 14% decrease on vehicle (P = 0.006), measured in skin biopsies [11].
- Population
- 29 adults with photodamaged forearm skin, 15 on tretinoin and 14 on vehicle, plus 26 healthy adults for the baseline comparison [11].
- Sources
- [11]
- Caveats
- One small trial measured a tissue marker, not appearance. The Renova label states adequate data have not shown increases in some other skin protein markers [9].
Tazarotene and adapalene for sun damage
Limited evidence: one trial each found tazarotene improved moderate sun damage over placebo, and one trial found it similar to tretinoin 0.05%.
Compared with placebo [7]; tretinoin 0.05% in one trial [7]
The numbers and sources
- Effect
- Tazarotene 0.01% to 0.1% improved moderate photodamage over placebo in one study, and one trial found tretinoin 0.05% equivalent to tazarotene 0.05% and 0.1%. Both caused skin irritation and redness [7].
- Population
- Adults with moderate photodamage of the face in single trials [7].
- Sources
- [7]
- Caveats
- One trial per comparison. No trial of adapalene for sun damage was found in the sources reviewed here.
Coarse wrinkles, dark spots and rough skin
Mixed results: a 2025 meta-analysis found tretinoin improved coarse wrinkles, but the Renova 0.02% trials did not show it for coarse wrinkles, pigment, roughness or sagging.
Compared with vehicle cream [8][9][10]
The numbers and sources
- Effect
- Tretinoin improved coarse wrinkles over vehicle (MD 0.245, 95% CI 0.119 to 0.370) [8]. A systematic review of 7 trials, using 0.025% and stronger for 3 to 24 months, reported improvement in wrinkling, mottled pigmentation, sallowness and sun spots in every study [10]. The Renova 0.02% label states no two of its five trials showed a benefit on coarse wrinkling, mottled hyperpigmentation, roughness or laxity [9].
- Population
- 1,361 patients in 8 trials [8]; 7 randomized trials, mostly in women [10]; 656 evaluable adults in 5 trials [9].
- Sources
- [8], [9], [10]
- Caveats
- The positive reviews included stronger concentrations than Renova's 0.02% [10]. Outcome scales differed between trials [10].
Tretinoin against other topical anti-aging products
Limited evidence: across 25 small studies, products such as retinol and retinaldehyde matched tretinoin in 13, beat it in 7 and fell short in 3, and irritated less.
Compared with other forms of vitamin A, such as retinol and retinaldehyde, and other cosmetic products [12]
The numbers and sources
- Effect
- In 25 studies comparing tretinoin with other topical products, the comparator gave better results in 7, equivalent results in 13 and poorer results in 3. Most studies found the comparator less irritating and better tolerated [12].
- Population
- 25 comparative studies to December 2023 [12].
- Sources
- [12]
- Caveats
- The review rated most studies poor quality or biased, and did not pool results [12].
Skin aging
Small trials found low-dose isotretinoin did not improve sun-aged skin more than sunscreen and moisturizer alone, and did no better than tretinoin cream.
Compared with sunscreen and moisturizer alone [7]; tretinoin 0.05% cream [8]
The numbers and sources
- Effect
- In women aged 40 to 55, isotretinoin 20 mg three times a week for 3 months gave no clinical or microscopic difference from sunscreen and moisturizer alone, apart from a small fall in the skin marker p53 [7]. In adults aged 50 to 75 with advanced photoaging, isotretinoin 20 mg every other day for 6 months did not differ from tretinoin 0.05% cream on appearance, histology or collagen [8].
- Population
- 32 women [7]; 24 adults, 22 completing [8].
- Sources
- [7], [8]
- Caveats
- Very small trials from one research group.
Preventing skin aging in young skin without sun damage
Not studied in people. The idea rests on collagen gains seen in already sun-damaged skin, and no trial tested starting tretinoin early to prevent aging.
No study in people. This rests on how it acts in the body.
The numbers and sources
- Effect
- In sun-damaged human skin, tretinoin raised collagen I formation [11]. The trials of wrinkles enrolled adults who already had photodamage [7][8].
- Population
- Adults with existing photodamage [7][8][11]. No trial in young people without it was found.
- Sources
- [11], [7], [8]
- Caveats
- Restoring collagen in damaged skin does not show what happens when undamaged skin is treated for years.
Peptides and SARMs
Skin aging and wrinkles
Limited evidence: one small trial found no difference in redness or wrinkles after laser resurfacing. A review reported less wrinkle volume with topical products.
The numbers and sources
- Effect
- In a randomized trial after carbon dioxide laser resurfacing around the mouth, skin care regimens with and without GHK-Cu did not differ in how fast redness resolved, judged by software and blinded evaluators, or in objectively rated wrinkles and skin quality at 12 weeks. Patients using GHK-Cu rated their improvement in overall skin quality higher on a validated questionnaire (p = 0.04) [3]. A 2026 systematic review of GHK-Cu in aesthetic medicine included 2 randomized trials among 20 studies and reported that GHK-Cu reduced wrinkle volume and depth compared with controls. Its abstract gives no figures [4].
- Population
- 13 patients completed the laser trial [3]. The review covered 2 randomized trials and 18 preclinical studies, searched through March 2026 [4].
- Sources
- [3], [4]
- Caveats
- Both reviews describe the human evidence as limited. One cites few well-designed trials and variable methods [4], and the other describes historical cosmetic reports as small or incompletely characterized [2]. These studies tested topical products, not injections.
Supplements
Skin aging
Shown to raise skin moisture and elasticity when taken by mouth. Wrinkle depth did not change significantly.
The numbers and sources
- Effect
- Oral astaxanthin raised skin moisture (SMD 0.53, 95% CI 0.05 to 1.01) and elasticity (SMD 0.77, 95% CI 0.19 to 1.35). Wrinkle depth did not change significantly (SMD -0.26, 95% CI -0.58 to 0.06) [8].
- Population
- 9 RCTs of oral astaxanthin, plus 2 open-label studies [8].
- Sources
- [8]
- Caveats
- Heterogeneity for elasticity was 75% [8].
Wrinkles and skin smoothness, oral
Small trials found one water-soluble CoQ10 reduced wrinkles and improved smoothness over 12 weeks. Hydration and dermis thickness did not change.
The numbers and sources
- Effect
- In 33 healthy adults, 50 or 150 mg a day of a water-soluble CoQ10 (Q10Vital) for 12 weeks reduced wrinkles and microrelief lines, improved smoothness and limited the seasonal decline in skin viscoelasticity against placebo. Skin hydration and dermis thickness did not change significantly [25]. In 34 women aged 40 to 65, a liquid supplement of the same CoQ10 with collagen for 12 weeks raised dermis density, reduced periorbital wrinkle area and total wrinkle score, and improved smoothness against placebo. Hydration, dermis thickness, transepidermal water loss and viscoelasticity did not change significantly [26].
- Population
- 33 healthy adults [25]; 34 healthy women, 17 per group [26].
- Sources
- [25], [26]
- Caveats
- Two small trials of one CoQ10 form, sharing authors. The second combined CoQ10 with collagen, so CoQ10's share of the effect is unknown [26].
Skin hydration, water loss and elasticity
Small trials found krill oil and fish oil raised skin hydration and lowered water loss. The krill trials were funded by the oil supplier.
The numbers and sources
- Effect
- In two placebo-controlled pilot trials, krill oil at 1 g a day (51 adults) or 2 g a day (50 adults) for 12 weeks lowered transepidermal water loss (from 14.47 to 13.83 and from 14.25 to 13.02 g/m²/h) and raised skin hydration and elasticity against placebo. The changes tracked the rise in omega-3 index [38]. In 60 people on hemodialysis with severe itch, 1,000 mg of fish oil (more than 900 mg EPA) twice a day for 3 months raised skin moisture on the face and arms, which did not rise on a soybean oil placebo, and itch scores fell [39]. A meta-analysis of 61 human diet and supplement studies found that lipids and fatty acids as a group improved skin hydration (pSMD 0.54, 95% CI 0.28 to 0.80) and elasticity (pSMD 0.49, 95% CI 0.14 to 0.83) and reduced wrinkles (pSMD -0.62, 95% CI -0.92 to -0.31) [40].
- Population
- Healthy adults with baseline water loss of more than 10 and up to 24.9 g/m²/h [38]; adults on maintenance hemodialysis [39]; participants in 61 studies [40].
- Sources
- [38], [39], [40]
- Caveats
- Two krill trial authors are employees of Aker BioMarine, which provided the krill and placebo oils and funded the study [38]. The meta-analysis grouped all lipids and fatty acids, so it does not isolate fish oil [40]. The hemodialysis abstract reports within-group changes [39].
Skin wrinkles and texture
One small trial found fewer facial wrinkles and less skin roughness than placebo at 3 g a day over 16 weeks.
The numbers and sources
- Effect
- On 3 g a day for 16 weeks, facial wrinkles and skin roughness improved against placebo (P < 0.05). In a second part, 1 g and 3 g a day improved wrinkles, firmness, elasticity and hydration from baseline [6].
- Population
- 20 participants in a placebo-controlled pilot, then 63 in a dose comparison without placebo [6].
- Sources
- [6]
- Caveats
- The larger part compared two doses with no placebo group, so its changes are from baseline [6].
Skin aging, Lactiplantibacillus plantarum HY7714
One trial found better skin hydration, elasticity and wrinkle depth than placebo with L. plantarum HY7714 in middle-aged adults with dry skin.
The numbers and sources
- Effect
- In 110 adults aged 41 to 59 with dry skin and wrinkles, 1 × 10^10 CFU a day of L. plantarum HY7714 for 12 weeks raised skin water content on the face (p < 0.01) and hands (p < 0.05), reduced water loss on the face and forearm more than placebo, and reduced wrinkle depth. Elasticity improved by 13.17% at 4 weeks (p < 0.05 against controls) and by 21.73% at 12 weeks (p < 0.01) [44].
- Population
- 110 volunteers [44].
- Sources
- [44]
- Caveats
- One trial of one strain. The authors call the findings preliminary [44].
Skin aging and wrinkles, oral
Limited evidence: higher dietary vitamin C was linked to a lower chance of a wrinkled appearance in 4,025 women. No supplement trial was located.
Compared with women with lower vitamin C intakes in the same survey [28]
The numbers and sources
- Effect
- In 4,025 US women aged 40 to 74, higher vitamin C intake was linked to lower odds of a wrinkled appearance (OR 0.89, 95% CI 0.82 to 0.96) and of senile dryness (OR 0.93, 95% CI 0.87 to 0.99), judged by dermatologists. The links held after adjusting for age, race, education, sun exposure, income, menopause, BMI, supplement use, activity and energy intake [28].
- Population
- 4,025 women in the first US National Health and Nutrition Examination Survey, with intake from one 24-hour recall [28]. Observational.
- Sources
- [28]
- Caveats
- Cross-sectional, with diet measured on one day, so it cannot show cause and confounding may remain. It describes vitamin C from the whole diet, not supplements [28].
Skin aging: hydration, elasticity and wrinkles
Mixed results: pooled trials found better skin hydration and elasticity, but the effect appeared only in industry-funded trials and not in high-quality trials.
The numbers and sources
- Effect
- Across 23 RCTs (1,474 participants), collagen improved skin hydration, elasticity and wrinkles overall. Trials without pharmaceutical company funding showed no effect on any of the three, while funded trials did. High-quality trials showed no effect in any category [6]. Two earlier meta-analyses, of 19 RCTs (1,125 participants, 95% women) and 26 RCTs (1,721 participants), reported improved hydration and elasticity against placebo [7][8].
- Population
- Adults aged 20 to 70, mostly women [7].
- Sources
- [6], [7], [8]
- Caveats
- The sources disagree. The pooled positive results [7][8] did not separate trials by funding source; when that was done, the effect was confined to funded trials [6].
Skin hydration and water loss, pooled across strains
Mixed results: one review found better skin hydration, water loss and wrinkles, while another found no benefit on skin water content.
The numbers and sources
- Effect
- Across 15 RCTs (867 healthy adults), oral probiotics raised skin hydration (5 RCTs, 402 people, SMD 1.208, 95% CI 0.410 to 2.006, I² 87.5%), lowered transepidermal water loss (6 RCTs, 453 people, SMD -1.165, 95% CI -1.402 to -0.927) and lowered wrinkle scores (4 RCTs, 287 people, SMD -1.299, 95% CI -1.736 to -0.863) against placebo. The effect on elasticity was inconclusive (2 RCTs, SMD 0.930, 95% CI -0.179 to 2.039) [39]. A 2022 meta-analysis of oral supplement trials found no benefit of lactic acid bacteria or Lactobacillus fermented foods on skin water content or transepidermal water loss [40]. A 2025 meta-analysis of 61 diet and supplement studies found that prebiotics and probiotics together improved hydration (pSMD 0.71, 95% CI 0.25 to 1.16) [41].
- Population
- Healthy adults [39][40]; participants in 61 human studies [41].
- Sources
- [39], [40], [41]
- Caveats
- These reviews pool different strains, so their estimates do not describe any one strain. The reviews disagree. The 2026 authors note frequent industry sponsorship, possible publication bias and certainty from very low to moderate [39].
Wrinkles, heat-killed Lactobacillus acidophilus IDCC 3302
One trial found no benefit over placebo on wrinkles from heat-killed L. acidophilus IDCC 3302 in adults with crow's-feet.
The numbers and sources
- Effect
- In 100 adults with crow's-feet wrinkles, 12 weeks of heat-killed L. acidophilus IDCC 3302 (ID-ACT 3302) showed no benefit over placebo on the primary wrinkle endpoints. Hydration, water loss and most elasticity measures improved in both groups. One elasticity index (R2) differed between groups, which the authors call exploratory [45].
- Population
- 100 healthy adults [45].
- Sources
- [45]
- Caveats
- Heat-killed bacteria, not live probiotics. Ildong Pharmaceutical funded the study and collaborated in its design and analysis, and one author is an employee [45].
Practices
Wrinkles and skin collagen
Small trials found less wrinkling and roughness and denser skin collagen after 4 to 15 weeks of red or near-infrared light, compared with sham or no treatment.
The numbers and sources
- Effect
- In 136 volunteers, 30 twice-weekly sessions of red or broader-spectrum light improved skin roughness by profilometry, collagen density by ultrasound, and blinded ratings of photographs compared with 23 untreated controls [28]. In a sham-controlled split-face trial of 76 people, 633 nm and 830 nm LED light twice a week for 4 weeks reduced wrinkles by up to 36% and raised elasticity by up to 19% from baseline [29]. In 20 women using a 630 nm LED mask twice a week for 3 months, wrinkle depth, firmness and dermal density improved progressively [30].
- Population
- 136 volunteers [28]. 76 people with facial wrinkles [29]. 20 healthy white women [30].
- Sources
- [28], [29], [30], [23]
- Caveats
- The largest trial compared with untreated controls, not a sham [28]. The mask study had no control group and tested one branded product [30]. A systematic review of 31 LED trials graded skin conditions other than acne, herpes and acute wound healing C or D, and noted small samples, absent blinding and missing sham controls in some studies [23].
Skin aging
Limited evidence: skin biopsies from 13 older men showed denser collagen and more blood vessels after 3 months of sessions, with no separate control group.
The numbers and sources
- Effect
- After 3 months of daily sessions, biopsies showed higher collagen density (effect size 1.10), longer elastic fibers (effect size 2.71), more blood vessels and fewer senescent cells than before treatment. Elastic fiber density and thickness did not change [17].
- Population
- 13 men with a mean age of 68 who agreed to repeated biopsies, out of a 70-person aging study. Each had a 3-month untreated period first [17].
- Sources
- [17]
- Caveats
- Thirteen self-selected men. The study measured tissue under a microscope, not wrinkles or appearance.
Skin aging
Limited evidence: no study tested infrared saunas on skin aging. Heat and infrared light on human skin raised enzymes that break down collagen and elastin, changes seen in sun-aged skin.
The numbers and sources
- Effect
- A 2009 review of studies in living human skin reports that infrared radiation and heat each induce new blood vessel growth and inflammatory cells, disrupt the dermal matrix by inducing matrix metalloproteinases, and alter dermal structural proteins, adding to premature skin aging [31]. In human skin heated in vivo, tropoelastin and the elastin-degrading enzyme MMP-12 rose, and fibrillin-1 fell in the dermis, a pattern the authors tie to the elastic fiber build-up of photoaged skin [32].
- Population
- Human skin exposed to heat or infrared in experimental studies [31][32].
- Sources
- [31], [32]
- Caveats
- These studies applied heat or infrared directly to skin, not whole-body sauna sessions, and measured tissue markers rather than wrinkles. No trial of infrared sauna and skin appearance was located.