AHK-Cu vs GHK-Cu: Which Is Better for Skin?
GHK-Cu wins this on evidence. It has human wound and skin data behind it. AHK-Cu has one unreplicated dish study and no human trial at all. Use GHK-Cu…
- AHK-Cu
- GHK-Cu
Best Interventions for Skin Health, Ranked by Evidence
Every intervention Outliyr has scored for skin health, ranked by its BioHarmony score for this use case rather than its overall rating. The number beside each name is how well that one thing works for skin health; the tier beside it is what it is worth once safety, cost and effort are counted across everything else.
54 of 109 evaluated interventions score 3.0+ out of 10 for skin health · 13 comparisons
Ranked for Skin Health
Category
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GHK-Cu
GHK-Cu scores 9.0/10 for skin beauty, with the best signal coming from Mulder et al. 1994. Topical GHK-Cu keeps its v0 score because cosmetic skin remains the strongest lane: wrinkle, firmness, collagen,…
Read the GHK-Cu report → -
Red Light Therapy
For skin-beauty, Red Light Therapy scores 8.2/10 because Wunsch 2014 found wrinkle reduction and collagen-density improvement after repeated red and near-infrared sessions. This is one of the cleaner consumer-relevant use cases because…
Read the Red Light Therapy report → -
Glycine
Glycine skin beauty earns 7.8/10 because Holecek 2025 anchors the most relevant signal. Glycine fits skin beauty because glycine participates in sleep signaling, glutathione, collagen, methylation, and nervous-system balance, depending on the…
Read the Glycine report → -
Astaxanthin
The skin resilience case for Astaxanthin is 7.5/10 because AAD reports AAD skin-cancer prevention guidance emphasizes SPF, shade, and UV avoidance; no astaxanthin endorsement surfaced. The score stays conditional because Astaxanthin still…
Read the Astaxanthin report → -
Melanotan I (Afamelanotide)
Melanotan I scores highest for skin-beauty because afamelanotide reliably increases pigmentation in human studies and improves repigmentation when paired with narrowband UV-B. The strongest cosmetic-adjacent clinical signal is the generalized vitiligo trial…
Read the Melanotan I (Afamelanotide) report → -
Lactoferrin
Skin-beauty score is driven mostly by acne, not collagen or photoaging. Kim 2010 tested lactoferrin-enriched fermented milk for acne, Chan 2017 tested lactoferrin with zinc and vitamin E in mild-to-moderate acne, and…
Read the Lactoferrin report → -
Collagen Peptides
Collagen Peptides fits skin beauty at 6.5/10 when the baseline problem is real. Proksch 2014 supports skin elasticity, Proksch 2014 wrinkle paper supports dermal matrix effects, but Myung 2025 weakens confidence in…
Read the Collagen Peptides report → -
TB-500 (Thymosin Beta-4 Fragment)
The 6.5/10 skin beauty score reflects evidence plus practical constraints. Skin-beauty is a secondary extrapolation from wound healing, angiogenesis, matrix remodeling, and anti-inflammatory pathways. Philp 2004 reported wound-healing and hair-follicle development effects…
Read the TB-500 (Thymosin Beta-4 Fragment) report → -
Infrared Sauna
On skin-beauty, Infrared Sauna deserves 6.5/10 because Kihara 2002 makes the claim plausible but incomplete. The existing rationale points to this narrower claim: Infrared sauna may improve skin appearance through blood flow,…
Read the Infrared Sauna report → -
Hyaluronic Acid
Skin is hyaluronic acid's strongest case at 6.5/10. Sun 2022 pooled 4 oral RCTs (196 adults) and found a small but significant hydration gain (SMD +0.40, p=0.007), and Hsu 2021 showed 120…
Read the Hyaluronic Acid report → -
Melanotan II
Melanotan II has a clear tanning effect, but the skin-beauty score is capped by safety and regulatory uncertainty. Human melanotropin trials showed tanning from subcutaneous administration, and the early MT-II pilot reported…
Read the Melanotan II report → -
Rapamycin
Rapamycin skin beauty earns 6.3/10 because Harrison 2009 anchors the most relevant signal. Rapamycin fits skin beauty when mTORC1 modulation, autophagy, immune aging, or senescence biology is the actual target. The score…
Read the Rapamycin report → -
Senolytics
Senolytics is a 6.2/10 option for skin beauty, especially where the context resembles Chang et al. 2016. Senescent fibroblast clearance fits skin-aging theory, but no human F+Q skin-aging outcome trial was verified…
Read the Senolytics report → -
Essential Amino Acids
The practical skin resilience read on Essential Amino Acids is 6.0/10 because Hagiyama 2024 reports 12 RCTs; 622 patients; low-certainty improvement in patient-reported outcomes and very-low-certainty strength signal after lower-limb surgeries. Wittholz…
Read the Essential Amino Acids report → -
Molecular Hydrogen
The skin resilience case for Molecular Hydrogen is 6.0/10 because Dhillon 2024 reports 25-article systematic review; mixed preliminary clinical evidence, heterogeneity, and need for stronger trials. Zhou 2024 points in the same…
Read the Molecular Hydrogen report → -
Vitamin C (Ascorbic Acid)
Skin gets a 6.0/10 because vitamin C's role here is mechanistically certain even where the cosmetic trial base is thin. As the essential cofactor for prolyl and lysyl hydroxylase, it is required…
Read the Vitamin C (Ascorbic Acid) report → -
Spermidine
On skin-beauty, Spermidine deserves 5.5/10 because Eisenberg 2016 makes the claim plausible but incomplete. The existing rationale points to this narrower claim: Autophagy gives a coherent skin-aging rationale, but verified human dermatology…
Read the Spermidine report → -
C60 (Buckminsterfullerene)
The skin-beauty use case for C60 (Buckminsterfullerene) receives a score of 5.5/10, reflecting the results of a modest human trial Kato 2010. C60 (Buckminsterfullerene) was applied topically in squalane for eight weeks…
Read the C60 (Buckminsterfullerene) report → -
Ca-AKG (Calcium Alpha-Ketoglutarate)
A 5.4/10 for skin-beauty fits Ca-AKG (Calcium Alpha-Ketoglutarate) because Demidenko 2021 supports direction more than certainty. The existing rationale points to this narrower claim: Mechanism via fibroblast epigenetic remodeling is possible, but…
Read the Ca-AKG (Calcium Alpha-Ketoglutarate) report → -
Methylene Blue
The practical skin-beauty read on Methylene Blue is 5.0/10 because Rodriguez 2016 anchors the strongest signal. The existing rationale points to this narrower claim: Skin-beauty use stays neutral-positive because topical dye and…
Read the Methylene Blue report → -
Hyperbaric Oxygen Therapy
Wound healing and radiation-injured tissue support skin repair, but beauty and anti-aging skin claims are weaker than medical wound care. Yang 2024 supports adjunctive wound healing in selected patients. Cosmetic skin rejuvenation,…
Read the Hyperbaric Oxygen Therapy report → -
Zone 2 Cardio
Zone 2 may improve skin appearance through circulation, lower inflammation, better glucose control, and sleep. It is not a direct cosmetic intervention like photobiomodulation, topical retinoids, or collagen-stimulating procedures.
Read the Zone 2 Cardio report → -
Polyphenols (Dietary)
Skin earns 4.5/10. Some polyphenols show photoprotective and elasticity signals in small trials, and the antioxidant mechanism is plausible, but dedicated outcome evidence for the dietary class is limited and not a…
Read the Polyphenols (Dietary) report → -
Shilajit
Neltner 2022 reported increased serum pro-c1alpha1, a type 1 collagen synthesis marker, after 8 weeks. Skin outcomes themselves were not measured.
Read the Shilajit report → -
Whole-Body Vibration
Cutaneous vasodilation is acute, not durable. Skin-tightening claims are not well-supported and itch can occur after WBV exposure.
Read the Whole-Body Vibration report → -
Metformin
AMPK and glycation mechanisms can support skin-aging hypotheses, but human cosmetic endpoint trials are not established. This remains preclinical or indirect through better glycemic control.
Read the Metformin report → -
Ergothioneine
Ergothioneine appears in cosmetic antioxidant formulations and protects skin cells from oxidative and UV stress in lab models, but oral skin-outcome human trials are sparse.
Read the Ergothioneine report → -
Berberine
Topical and antimicrobial traditions create a plausible acne and skin-inflammation angle, but oral berberine has thin direct evidence for skin-beauty outcomes. Users with insulin resistance may see indirect acne benefit through glucose…
Read the Berberine report → -
Taurine
Taurine has antioxidant and osmoregulatory mechanisms that could matter for skin biology, but direct skin-beauty RCTs are sparse. This is not a primary reason to use taurine.
Read the Taurine report → -
Traditional Sauna (Finnish Dry-Heat)
Skin scores 4.0/10. Sauna increases skin blood flow and sweating, which some users feel improves skin tone, but there is no robust outcome evidence for skin appearance or aging from traditional dry…
Read the Traditional Sauna (Finnish Dry-Heat) report → -
BPC-157
Wound healing and collagen synthesis support skin repair, especially in injury or wound contexts. It is not a cosmetic skin intervention with human photoaging trials, unlike red light therapy or retinoids.
Read the BPC-157 report → -
Thymosin Beta-4 (Tβ4)
Skin benefits beyond wound healing have no dedicated human Tβ4 trial. The mechanism of accelerated keratinocyte migration and angiogenesis is plausible for post-procedure or cosmetic-repair use, and the RGN-137 wound program shows…
Read the Thymosin Beta-4 (Tβ4) report → -
Omega-3
Skin evidence is modest and heterogeneous, strongest for inflammatory skin conditions rather than cosmetic beauty. Effects are not comparable to topical retinoids or light-based dermatology.
Read the Omega-3 report → -
Ketogenic Diet
Skin response is mixed. Some acne-prone users improve through lower insulin and IGF-1 signaling, while others develop prurigo pigmentosa or worsen skin quality through low fiber, low micronutrient variety, or endocrine stress.…
Read the Ketogenic Diet report → -
Curcumin
Only pilot-sized trials exist, mostly topical, for conditions like psoriasis where a niosomal curcumin pilot suppressed inflammatory gene expression. Underpowered and not pooled into an effect size. Promising but early.
Read the Curcumin report → -
Glutathione (GSH)
Skin scores 4.0/10 despite being glutathione's most-marketed use, because the evidence does not match the hype. Weschawalit 2017, the headline oral skin RCT, found the melanin index only trended lower without reaching…
Read the Glutathione (GSH) report → -
Quinton Marine Plasma (Seawater Minerals)
A 33-person uncontrolled before-and-after in atopic dermatitis (Hataguchi 2005) reported skin improvement and shifted mineral status, but the absence of a control arm makes it weak evidence.
Read the Quinton Marine Plasma (Seawater Minerals) report → -
TRT (Testosterone Replacement Therapy)
TRT is not a skin-beauty intervention. Androgen exposure can increase oiliness and acne, especially in DHT-sensitive users or high-peak injection protocols. Any collagen or body-composition benefit is secondary.
Read the TRT (Testosterone Replacement Therapy) report → -
Resveratrol
Skin-beauty claims are stronger for topical antioxidant products than oral capsules. Oral resveratrol faces low parent-compound bioavailability and no strong human skin-aging endpoint trial comparable to device-based photobiomodulation or topical retinoids. Szymkowiak…
Read the Resveratrol report → -
CJC-1295
GH/IGF-1 axis promotes collagen synthesis and skin thickness; community reports improved skin quality. This remains indirect because Teichman 2006 measured hormone response, not skin endpoints.
Read the CJC-1295 report → -
Tirzepatide
Tirzepatide has no direct skin quality trial. Weight loss may improve obesity linked inflammation and insulin related skin issues for some users. Rapid fat loss can also worsen facial volume loss, skin…
Read the Tirzepatide report → -
Thymosin Alpha-1
Skin benefit is indirect through wound and immune regulation. There is no acne, collagen, photoaging, or hair-follicle human evidence comparable to dermatologic photobiomodulation or retinoid trials.
Read the Thymosin Alpha-1 report → -
Colostrum
Skin-beauty claims are mostly anecdotal. Growth-factor and dairy-bioactive mechanisms are possible at the gut and immune level, but direct human skin RCTs for oral bovine colostrum remain limited.
Read the Colostrum report → -
NMN (Nicotinamide Mononucleotide)
Skin-aging evidence is limited and not central to the verified NMN human base. Current stronger citations are metabolic and NAD+ trials, not dermatology endpoints.
Read the NMN (Nicotinamide Mononucleotide) report → -
C15 (Pentadecanoic Acid)
No human C15:0 supplementation trial has measured wrinkles, skin hydration, transepidermal water loss, acne, sebum, or validated dermatology quality scores. Robinson 2024 (Robinson 2024) did not include skin endpoints. The membrane-lipid hypothesis…
Read the C15 (Pentadecanoic Acid) report → -
Vitamin D3 + K2
Thin evidence base for D3+K2 on skin endpoints. VDR expression in keratinocytes is well-documented but no robust RCT exists for D3 supplementation on skin barrier, photoaging, or pigmentation. Topical D3 preparations (calcipotriol)…
Read the Vitamin D3 + K2 report → -
Coenzyme Q10 (CoQ10 / Ubiquinol)
Topical CoQ10 has limited antioxidant skin-aging data, but oral CoQ10 for skin lacks strong human outcome trials; mostly mechanistic optimism.
Read the Coenzyme Q10 (CoQ10 / Ubiquinol) report → -
KPV (Lys-Pro-Val)
Alpha-MSH fragments have documented anti-inflammatory skin effects, and Sung 2025 found KPV reduced PM10-induced inflammatory signaling in keratinocyte and 3D skin models, but direct human dermatology evidence is absent.
Read the KPV (Lys-Pro-Val) report → -
Spirulina
Carotenoid and antioxidant content gives a plausible skin rationale, but human skin-outcome trials are minimal.
Read the Spirulina report → -
Ashwagandha
Skin-beauty support is indirect. Stress and inflammation can worsen skin quality, and antioxidant pathways may help, but the audit found no dedicated dermatology RCT to elevate this score. Use red light therapy,…
Read the Ashwagandha report → -
Fucoidan (Brown Seaweed Polysaccharide)
Topical and cosmetic uses are preclinical; no oral human skin-outcome evidence.
Read the Fucoidan (Brown Seaweed Polysaccharide) report → -
Tesamorelin
GH/IGF-1 can influence dermal thickness and collagen turnover, but tesamorelin has no strong skin-aging RCT evidence. Any skin benefit is indirect and should not drive use.
Read the Tesamorelin report → -
Semaglutide
Rapid fat loss can create loose skin and facial volume loss; semaglutide is not a collagen or skin-quality intervention.
Read the Semaglutide report → -
Pine Pollen
Antioxidant content gives a plausible cosmetic rationale, but there is no human skin-outcome study for oral or topical pine pollen.
Read the Pine Pollen report →
Nothing matches those filters.
Comparisons that judge skin health
Head-to-head reports and category rankings that name a winner on this use case.
BPC-157 vs KPV: Which Is Better for Gut Healing?
BPC-157 for structural repair, KPV for inflammation you cannot afford to stimulate. BPC-157 scores gut health 9.0 against KPV's 7.0 and wins nearly every other row, because it…
- BPC-157
- KPV
Colostrum vs Collagen Peptides: Which Should You Buy?
These two get sold as the same thing, a scoop for gut and skin, and they share almost no mechanism. Colostrum is a gut and immune product: gut…
- Colostrum
- Collagen Peptides
HBOT vs Red Light Therapy: Which Is Better for Recovery?
Buy the panel. Red light therapy scores 8.0 against HBOT's 6.2, costs $17 to $43 a month against $3,000 to $6,000, and does not lose a single use…
- Hyperbaric Oxygen Therapy
- Red Light Therapy
Melanotan I vs Melanotan II: Which Is Safer for Tanning?
Melanotan I is the safer tanning peptide and it scores higher, 6.2 against 4.6. Both darken skin through the same receptor. Melanotan II hits three more receptors, which…
- Melanotan I
- Melanotan II
Sermorelin vs Ipamorelin: Which Is Better for Fat Loss?
Start on sermorelin. Ipamorelin scores higher overall, yet sermorelin wins thirteen of the sixteen shared use cases and it is the one an anti-aging clinic actually prescribes. Ipamorelin…
- Sermorelin
- Ipamorelin
Lactoferrin vs Colostrum: Which Is Better for Immunity?
Lactoferrin scores 7.3 against colostrum's 6.8, and lactoferrin is one protein inside colostrum. Buy lactoferrin when iron handling, acne or H. pylori is the target, at $25 to…
- Lactoferrin
- Colostrum
PT-141 vs Melanotan II: Which Is Better for Libido?
PT-141 scores 5.4 and melanotan II 4.6, and both land in the neutral tier. PT-141 is the defensible one. It targets the brain receptor that drives desire, it…
- PT-141
- Melanotan II
Rapamycin vs Metformin: Which Is Better for Longevity?
Metformin scores 6.9 and rapamycin 6.8, which settles nothing. Rapamycin owns the aging-biology rows: longevity 8.0, autophagy 8.5, senescence 7.8, plus replicated mouse lifespan data. Metformin owns everyday…
- Rapamycin
- Metformin
Red Light Therapy vs Infrared Sauna: Which Should You Buy?
Red light therapy scores 8.0 and infrared sauna 7.4, so buy the panel first. It costs less, targets skin, hair, joints and recovery directly, and carries higher evidence…
- Red Light Therapy
- Infrared Sauna
Taurine vs Glycine: Which Amino Acid Should You Take?
Taurine scores 8.1 and glycine 7.9, close enough that the overall numbers pick nothing. Taurine wins cardiovascular and metabolic endpoints outright. Glycine wins antioxidant, skin and connective tissue.…
- Taurine
- Glycine
Traditional Sauna vs Infrared Sauna: Which Should You Buy?
Traditional sauna scores 7.7 and infrared 7.4. Infrared actually scores higher on 20 of the 23 use cases both are rated on. Buy traditional anyway if hard outcomes…
- Traditional Sauna
- Infrared Sauna
Questions about skin health
What scores highest for skin health?
GHK-Cu, at 9.0 out of 10 for skin health. GHK-Cu scores 9.0/10 for skin beauty, with the best signal coming from Mulder et al.
What is the cheapest thing that works for skin health?
Of the top-scoring options, Glycine is the least expensive at about $2 a month, scoring 7.8 out of 10 for skin health.
How many interventions has Outliyr scored for skin health?
54 of the 109 interventions evaluated for skin health score 3.0 out of 10 or better, which is the cut-off for appearing on this page.
