Acute impact of afamelanotide on UVR erythemal and melanogenic responses in healthy humans in vivo: an exploratory study.

Griffin LL, Kiss O, Halai P, Langton AK, Rhodes LE, Farrar MD

Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology1 Sept 2026

PMID42678656DOI10.1007/s43630-026-00986-xPepBankPUB-42678656

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Summary

Afamelanotide, an analogue of α-melanocyte stimulating hormone, activates the melanocortin-1 receptor and has a range of protective properties as demonstrated largely in vitro. While afamelanotide is approved to treat a visible light-induced inflammatory dermatosis, erythropoetic protoporphyria, its acute effects in vivo are poorly characterised. We explored short-term effects of afamelanotide on the acute inflammatory response of UVR-induced erythema and on the melanogenic response, in healthy humans. Participants (n = 9, 5 M:4 F, 27-43y, phototypes II-III) had melanin density and skin lightness measured at six skin sites using spectrophotometry. A broadband UVB dose-series (7-80 mJ/cm² erythemally-weighted UVR, Philips TL12) was applied to buttock skin. After 24 h, minimal erythema dose (MED) was assessed, spectrophotometric measurements were taken of erythema at each dose site and two unexposed sites, and an unexposed site was biopsied. Afamelanotide was administered (16 mg subcutaneous implant) and after six days the same UVR dose-series applied to contralateral buttock skin, and measurements and biopsy repeated. Melanin was stained in biopsy sections (modified Warthin-Starry method) and quantified by image analysis. The UVR-erythema dose response (area-under-curve) decreased post-afamelanotide (mean 3.5 pre, 2.7 post, P = 0.018) with an apparent increase in MED (median 21 mJ/cm² pre, 29.9 post, not sign.). Melanin density (reflectance at 420 and 400 nm) increased (mean overall increase 2.4% to 2.9%, P = 0.001), while melanin staining was unaltered. The demonstrated protection against acute UVR-induced erythema shortly after afamelanotide application supports that anti-inflammatory effects observed in vitro may operate in vivo, warranting further investigation in acute UVR-induced inflammatory conditions.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study4

4 results from studies that gave the peptide. 4 results from people.

01HumanNon-randomized trialEfficacy outcome
In healthy adults, the UVR-erythema dose response decreased six days after a 16 mg afamelanotide implant (mean 3.5 before, 2.7 after).
In plain wordsIn healthy adults, skin redness after UV light was lower six days after an afamelanotide implant than before.
Peptide
Melanotan I (afamelanotide)
Outcome
DecreaseUVR-erythema dose response (area under curve)
Study
n = 9
Comparator
Pre-afamelanotide (same participants)
Outcome group
Skin and hair · Skin and wound
Studied dose
16 mg · subcutaneous implant · 6 daysAs given in this study (human).
Measurements
UVR-erythema AUC mean
3.5
pre-afamelanotide
UVR-erythema AUC mean
2.7
post-afamelanotide
Source sentences
Summary
The UVR-erythema dose response (area-under-curve) decreased post-afamelanotide (mean 3.5 pre, 2.7 post, P = 0.018)
2 context sentences(design, population, supporting numbers)
Summary · context
Participants (n = 9, 5 M:4 F, 27-43y, phototypes II-III) had melanin density and skin lightness measured at six skin sites using spectrophotometry.
Summary · context
Afamelanotide was administered (16 mg subcutaneous implant) and after six days the same UVR dose-series applied to contralateral buttock skin, and measurements and biopsy repeated.
Show in the study text Report a problemFND-4267865601
02HumanNon-randomized trialEfficacy outcome
In healthy adults, the minimal erythema dose showed an apparent increase after afamelanotide (median 21 mJ/cm2 before, 29.9 mJ/cm2 after) that was not significant.
In plain wordsIn healthy adults, the UV dose needed to cause redness seemed higher after afamelanotide, but the difference was not significant.
Peptide
Melanotan I (afamelanotide)
Outcome
No significant changeMinimal erythema dose
Study
n = 9
Comparator
Pre-afamelanotide (same participants)
Outcome group
Skin and hair · Skin and wound
Studied dose
16 mg · subcutaneous implant · 6 daysAs given in this study (human).
Measurements
MED median
21 mJ/cm2
pre-afamelanotide
MED median
29.9 mJ/cm2
post-afamelanotide
Source sentences
Summary
an apparent increase in MED (median 21 mJ/cm² pre, 29.9 post, not sign.).
2 context sentences(design, population, supporting numbers)
Summary · context
Participants (n = 9, 5 M:4 F, 27-43y, phototypes II-III) had melanin density and skin lightness measured at six skin sites using spectrophotometry.
Summary · context
Afamelanotide was administered (16 mg subcutaneous implant) and after six days the same UVR dose-series applied to contralateral buttock skin, and measurements and biopsy repeated.
Show in the study text Report a problemFND-4267865602
03HumanNon-randomized trialEfficacy outcome
In healthy adults, melanin density measured by reflectance at 420 and 400 nm increased after afamelanotide (mean overall increase 2.4% to 2.9%).
In plain wordsIn healthy adults, skin melanin readings were higher six days after an afamelanotide implant than before.
Peptide
Melanotan I (afamelanotide)
Outcome
IncreaseMelanin density (spectrophotometry)
Study
n = 9
Comparator
Pre-afamelanotide (same participants)
Outcome group
Pigmentation · Skin and wound
Studied dose
16 mg · subcutaneous implant · 6 daysAs given in this study (human).
Source sentences
Summary
Melanin density (reflectance at 420 and 400 nm) increased (mean overall increase 2.4% to 2.9%, P = 0.001)
2 context sentences(design, population, supporting numbers)
Summary · context
Participants (n = 9, 5 M:4 F, 27-43y, phototypes II-III) had melanin density and skin lightness measured at six skin sites using spectrophotometry.
Summary · context
Afamelanotide was administered (16 mg subcutaneous implant) and after six days the same UVR dose-series applied to contralateral buttock skin, and measurements and biopsy repeated.
Show in the study text Report a problemFND-4267865603
04HumanNon-randomized trialEfficacy outcome
In healthy adults, melanin staining in skin biopsies was unaltered after afamelanotide.
In plain wordsIn healthy adults, melanin staining in skin samples did not change after an afamelanotide implant.
Peptide
Melanotan I (afamelanotide)
Outcome
No significant changeMelanin staining in biopsies
Study
n = 9
Comparator
Pre-afamelanotide (same participants)
Outcome group
Pigmentation · Skin and wound
Studied dose
16 mg · subcutaneous implant · 6 daysAs given in this study (human).
Source sentences
Summary
while melanin staining was unaltered.
3 context sentences(design, population, supporting numbers)
Summary · context
Melanin was stained in biopsy sections (modified Warthin-Starry method) and quantified by image analysis.
Summary · context
Participants (n = 9, 5 M:4 F, 27-43y, phototypes II-III) had melanin density and skin lightness measured at six skin sites using spectrophotometry.
Summary · context
Afamelanotide was administered (16 mg subcutaneous implant) and after six days the same UVR dose-series applied to contralateral buttock skin, and measurements and biopsy repeated.
Show in the study text Report a problemFND-4267865604

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Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
13 Oct 2026, 21:44 UTC
Study results updated
Version 1
13 Oct 2026, 16:31 UTC
First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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Journal Article

Keywords

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