Regenerative aesthetics is the least regulated area of medicine we write about. Here is what the trials found, what they measured, and which two treatments still have the best evidence of anything.
What Actually Ages Skin
Skin ageing has two drivers, and they are not equally treatable.
Intrinsic (chronological) ageing — dermal fibroblasts progressively lose the ability to produce and maintain collagen. Collagen fibrils undergo progressive loss and fragmentation, producing thin, structurally weakened skin. This creates a self-perpetuating cycle: fragmented collagen alters the environment fibroblasts sit in, which further impairs their function [1].
Extrinsic ageing — predominantly photoageing from ultraviolet radiation [2], along with smoking, pollution and glycation.
⚠️ The distinction is practical, not academic. Photoageing is largely preventable, and the intervention that prevents it is inexpensive and proven. Intrinsic ageing is not preventable, and everything on this page addresses it only partially.
What Is Actually Proven
This section comes first because the evidence here is stronger than anything that follows it.
Sunscreen — the only intervention shown to prevent skin ageing
A randomised controlled community trial followed 903 adults for 4.5 years, randomly assigning them to daily broad-spectrum sunscreen or discretionary use, with skin ageing graded from skin-surface microtopography by assessors blinded to allocation [3].
- The daily-sunscreen group showed no detectable increase in skin ageing over 4.5 years
- Skin ageing was 24% less than in the discretionary-use group — relative odds 0.76 (95% CI 0.59–0.98)
- β-carotene supplementation had no overall effect
The authors' limitation, stated: some outcome data were missing and power to detect moderate effects was modest.
No procedure on this page has evidence of this quality, and none of them prevents anything.
Tretinoin — decades of randomised evidence, including histology
A 16-week randomised, double-blind, vehicle-controlled trial of topical tretinoin for photoageing [4]:
- All 30 completers showed statistically significant improvement on the tretinoin-treated forearm and not on the vehicle-treated forearm
- 14 of 15 patients who received facial tretinoin improved; none of the vehicle-treated faces did
- Statistically significant histologic changes were seen in tretinoin-treated skin — changes in the tissue itself, confirmed on biopsy
- Side effects were limited to irritation of treated skin
⚠️ Two things follow from this that are commonly stated the other way round. Tretinoin's effects are not confined to the skin surface — they were confirmed histologically in the dermis. And no treatment described further down this page has been shown to produce histologically confirmed change in human skin.
The honest framing: sunscreen and a retinoid are the foundation. Procedures are what you add once that foundation exists — not a substitute for it.
Platelet-Rich Plasma: What the Trials Found
PRP has the best evidence of any regenerative aesthetic treatment. It is important to be precise about how good that is.
The overall picture
The most recent and highest-tier appraisal is an overview of systematic reviews — 13 systematic reviews published 2015–2023, covering 114 overlapping reports based on 28 individual primary studies, of which 18 were uncontrolled [6]. Its findings:
- Meta-analysis was possible in only 1 of the 13 reviews. It found patients treated with PRP as an adjunct had increased satisfaction over controls: mean difference 0.63 (95% CI 0.25–1.00), p = 0.001 — low certainty, downgraded for risk of bias and inconsistency
- Four reviews concluded descriptively that PRP combined with laser therapy increased satisfaction and skin elasticity and reduced erythema — very low certainty, downgraded for imprecision, unsystematic observation and risk of bias
- Adverse events were a predefined outcome in only 2 of the 13 reviews
That is the state of the evidence: mostly uncontrolled studies, one meta-analysable outcome, low certainty, and safety rarely measured systematically.
The randomised placebo-controlled trial
One trial answers the question directly: a split-face, saline-controlled, double-masked randomised trial in JAMA Dermatology [5]. Each participant received PRP into one cheek and sterile normal saline into the other — the strongest available design, because each participant is their own control.
Primary outcome — photoaging scores rated by two masked dermatologists: no significant difference between PRP and saline, at 2 weeks, 3 months or 6 months, on any of the four subscores.
Secondary outcome — participants' own assessment, 6 months after a single treatment: significantly better on the PRP side for texture (2.00 vs 1.21, P = .02) and wrinkles (1.74 vs 1.21, P = .03).
The authors' conclusion: "Both participants and raters found PRP to be nominally but not significantly superior to normal saline." Of 27 enrolled, 19 were analysed.
⚠️ The disagreement between the blinded raters and the patients is the most informative result on this page, and it should not be resolved in either direction. It may mean PRP produces a change patients feel and standardised photoaging scales do not capture. It may mean patients who received an injection into one cheek and knew a study was under way rated that side more favourably. The trial cannot distinguish these, and neither can we.
What varies by outcome measure
A 2025 systematic review of 20 studies and 514 patients broke results down by which parameter was measured [7]. Significant improvement was reported in:
This explains a great deal of the apparent contradiction in the field. PRP looks effective when you measure skin thickness and elasticity, and ineffective when you measure pigmentation and hydration. Anyone quoting a single "PRP works / doesn't work" figure has chosen an outcome.
The systematic review most often quoted
A systematic review of 24 studies including 8 RCTs, covering 480 patients receiving PRP, concluded that injected PRP monotherapy "was shown to at least temporarily induce modest improvement in facial skin appearance, texture, and lines", that adjuvant PRP accelerated healing after fractional laser resurfacing, and that "the degree of improvement was typically less than 50%" though patients generally reported high satisfaction [8].
Its stated limitations: heterogeneity in how PRP is prepared and administered, and lack of standardisation in outcome measures. Its stated unknowns: "The persistence of these effects is not known", and more high-quality trials with sufficient follow-up are needed to optimise treatment regimens.
⚠️ There is no established optimal treatment schedule for PRP in skin rejuvenation. Protocols in use — including ours — are conventions, not findings.
Smaller studies, described accurately
An uncontrolled study of 20 subjects given a single intradermal PRP injection and assessed over 8 weeks found mean Wrinkle Severity Rating Scale scores fell from 2.90 ± 0.91 to 2.10 ± 0.79, with 14 of 17 subjects with nasolabial folds showing more than 25% improvement [9].
⚠️ This study had no control group and no blinding described. Before-and-after appearance studies without a control arm are the most placebo-susceptible design in medicine, and the result should be read as consistent with the controlled evidence rather than as independent confirmation of it.
A split-face study in 50 patients aged 17–32 with atrophic acne scars compared microneedling plus PRP (injected and applied topically) against microneedling plus intradermal distilled water, three sessions at one-month intervals. Improvement on Goodman's Quantitative scale was 62.20% versus 45.84% [10].
⚠️ This is acne scarring in young adults, not photoageing in older skin. It supports combining PRP with microneedling for scars. It does not transfer to wrinkle reduction at 55.
Microneedling
Microneedling has an evidence base of its own that does not depend on PRP. A systematic review restricted to randomised controlled trials identified nine RCTs in atrophic acne scars and found microneedling efficacious as monotherapy and in combination, with no serious adverse effects reported in any of the included studies [11]. The authors note that larger samples and longer follow-up are still needed.
Worth being clear about: in the combination studies above, some of the benefit attributed to PRP belongs to the microneedling.
Exosomes, and What "Stem Cell" Means on a Label
What the clinical evidence covers
The best clinical evidence for exosomes in skin is a 12-week prospective, double-blind, randomised, split-face trial in 25 patients [12]. It is a genuinely well-designed study, and its scope is narrow:
- Patients received three sessions of fractional CO2 laser to the whole face
- Afterwards, one side received an adipose-tissue stem-cell-derived exosome gel and the other a control gel
- Result: 32.5% vs 19.9% reduction in acne-scar score (ECCA), p < 0.01
- Treatment-related erythema was milder and downtime shorter on the exosome side
What this supports: exosome gel as an adjuvant to laser resurfacing for atrophic acne scars. That is a real finding with a proper control.
What it does not support: exosomes as a standalone treatment, exosomes for wrinkles or photoageing, or exosomes applied without a resurfacing procedure. Beyond this indication, the human evidence is thin. Much of the supporting literature is laboratory work and animal models — the frequently cited demonstration that fibroblast-derived exosomes increase procollagen and reduce MMP-1 was performed in vitro and in a nude mouse photoageing model [13], and mouse skin is not human skin.
⚠️ The label problem
This is the most useful thing on this page if you are buying skincare.
"Stem cell" on a cosmetic product usually does not mean living human stem cells. In practice the term is applied to:
- Plant stem cell extracts — apple, edelweiss, grape. Plant cells cannot function in human skin. These are botanical extracts, and whatever merit they have is as antioxidants, not as cell therapy
- Conditioned medium — the liquid cells were grown in, after the cells are removed. It contains secreted proteins; it contains no cells
- Lysates or "cell extract" — deliberately destroyed cells
Even in the clinical literature the naming is inconsistent enough that reviews have been written specifically to clarify nomenclature across nanofat, stromal vascular fraction, adipose-derived stem cells and extracellular vesicles — because the terms are used interchangeably when they refer to materially different things [14].
The regulatory line. A cosmetic may make claims about appearance. A product claiming to alter the structure or function of skin is making a drug claim, which requires approval that topical exosome and "stem cell" cosmetics have not obtained. Products in this category are frequently sold as cosmetics while being marketed in structural language.
What to ask: Does this contain living human cells? If not, what does it contain? If the answer is a plant extract or a conditioned medium, it is not cell therapy, whatever the packaging says.
Summary of the Evidence
Safety: The Part That Matters Most
PRP uses your own blood, so allergic reaction to the product is essentially impossible. Expected effects are bruising, swelling and redness, typically resolving in 1–3 days. Microneedling may cause temporary sensitivity and peeling.
### ⚠️ Cosmetic injection procedures have transmitted HIV
In 2018 the New Mexico Department of Health was notified of an HIV diagnosis in a woman with no known risk
factors who had received platelet-rich plasma microneedling facials — "vampire facials" — at a spa.
The investigation identified four former clients of that spa and one sexual partner diagnosed with HIV
between 2018 and 2023. Nucleotide sequence analysis showed highly similar viral strains across all cases.
The report states that HIV transmission through cosmetic injection services had **not been previously
documented** [16].
What failed is specific and checkable. The facility was unlicensed, **did not follow recommended
infection control procedures, and did not maintain client records** — so when infections were found,
tracing and notifying other clients was obstructed.
This does not make PRP dangerous. It makes where you have it done the single most important decision you make.
Before any procedure involving needles and blood, confirm:
- The facility is licensed for the procedure, and the practitioner is qualified and named
- Blood is drawn, processed and reinjected as a closed, single-patient process, with single-use disposables opened in front of you
- Client records are maintained — this is what makes you contactable if a problem is found later
- Nothing is shared between clients — not devices, not needle cartridges, not vials, not centrifuge tubes
- You can ask what the product is and get a straight answer
Anyone who is offended by these questions has answered them.
What We Offer
⚠️ We do not offer topical "stem cell" products or standalone exosome treatments, because the evidence does not support them as skin rejuvenation and the category is poorly regulated.
We will also tell you if the honest answer is sunscreen and a retinoid. For many people arriving with early photoageing, that is the answer, and it costs a fraction of any procedure.
Who this suits
Reasonable candidates: adults with early-to-moderate visible ageing or acne scarring, who already use daily photoprotection, want gradual improvement, and understand the evidence is modest.
Not suitable: severe skin laxity (a surgical question) · active skin infection, autoimmune skin disease or active acne · anyone expecting a procedure to substitute for photoprotection · anyone expecting dramatic change.
Frequently Asked Questions
Q: Does PRP actually work?
A: Partly, modestly, and depending on what you measure. Patients in the one placebo-controlled trial rated their PRP-treated side significantly better for texture and wrinkles; masked dermatologists scoring the same faces found no significant difference [5]. Across the literature, significant improvement is reported in 80% of studies measuring skin thickness and 0% measuring hydration [7]. The most reliable summary is that PRP produces modest, at least temporary improvement, of unknown duration [8].
Q: How is this different from fillers?
A: Fillers add volume immediately and temporarily. PRP does not add volume; it aims to improve skin quality gradually. They address different things and are often used together.
Q: Is this the "vampire facial"?
A: The procedure is microneedling with PRP, which is what that name refers to. The name is media shorthand. What matters is not the name but the setting — see the safety section above, and the documented HIV cluster traced to an unlicensed spa offering exactly this procedure [16].
Q: How many sessions will I need?
A: ⚠️ There is no evidence-established optimal schedule. The systematic review covering this literature explicitly states that more trials with sufficient follow-up are needed to optimise treatment regimens [8], and that the persistence of effects is not known. Common practice is 2–3 initial sessions with periodic maintenance; that is convention rather than a finding, and we will say so rather than present it as research-derived.
Q: I have darker skin — is this safe for me?
A: PRP and microneedling avoid the thermal injury that drives post-inflammatory hyperpigmentation risk with laser treatments in Fitzpatrick types IV–VI, which is a genuine practical advantage. We are not aware of a study specifically establishing comparative safety across all skin types, so this is reasoning from mechanism rather than from trial data, and it should be discussed with a practitioner experienced in treating your skin type.
Q: What about exosome facials?
A: The good evidence covers exosome gel applied after fractional CO2 laser, for acne scars [12]. Outside that, human evidence is limited and much of the supporting work is laboratory and animal research [13]. Products sold as exosome or "stem cell" facials frequently contain no living human cells at all.
Q: What has the strongest evidence of anything on this page?
A: Daily sunscreen [3]and topical tretinoin [4]— by a wide margin, and neither is a procedure.
The Bottom Line
Skin ageing is partly preventable and partly not. The preventable part responds to daily photoprotection, and that is proven in a randomised trial [3]. The visible damage already present responds to tretinoin, proven in a double-blind vehicle-controlled trial with histology [4].
PRP adds a modest amount on top of that foundation — enough that patients notice it, not always enough that blinded assessors do, and for a duration nobody has established [5][6][8]. Microneedling has genuine evidence for scarring [11]. Exosomes have one good trial, in acne scars, after laser [12].
None of it reverses ageing, and anything sold on that basis is being sold dishonestly.
If you want the most from your skin: protect it daily, use a retinoid, choose a licensed practitioner who will show you their infection control, and treat procedures as an addition rather than a replacement.