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Canthaxanthin (oral tanning agent)
A food-colouring carotenoid taken in high doses to bronze the skin. It works — and it deposits dose-dependent crystals in the retina, and a fatal aplastic anaemia has been reported in a healthy young woman who took it for tanning. Not approved as a tanning agent in the US or EU.
Research compound — not a dietary supplement
Canthaxanthin is a research compound, not a regulated dietary supplement. It is sold for research or off-label use. The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most Canthaxanthin studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from medium-quality studies published 1990–2026 with a typical study size of 1 participants.
Based on 4 studies · 37 total participants
Confidence
Very low confidenceBy outcome
Scores near the floor because the only well-documented human literature is toxicological. That it colours the skin is not in dispute and is not a health benefit; what has been studied is the retinal deposition it causes. There is no controlled trial of benefit for any use at tanning doses.
Canthaxanthin is a red-orange carotenoid used legitimately as a food colourant at low levels. Taken in the far larger doses sold as "tanning pills", it deposits in subcutaneous fat and the stratum corneum and gives the skin a bronze-orange cast that reads as a tan at a glance.
It also deposits in the retina, forming birefringent yellow-to-red crystals in a ring around the macula — canthaxanthin retinopathy — and the deposition is dose-dependent.
Most people with the crystals are asymptomatic and the finding is usually reversible after stopping, but clearance is slow, taking up to about twenty years in long-term follow-up, and cases of significant visual loss are reported.
Separately and more seriously, JAMA reported a previously healthy young woman who developed aplastic anaemia with a fatal outcome after taking canthaxanthin supplied by a commercial tanning salon; the authors noted that no safety investigation of oral canthaxanthin in humans had been conducted, so the true frequency of bone-marrow suppression is simply unknown.
It is not approved as a tanning agent by the FDA or in the EU. This entry exists so that someone who scans a product or types the name is told what it is, rather than being told it could not be identified.
At tanning doses the pigment accumulates in subcutaneous fat and the stratum corneum, producing a bronze-orange colour that is a deposit rather than melanin.
The same lipophilic deposition occurs in the retina, forming birefringent yellow-to-red crystals in a doughnut-shaped ring around the macula. Deposition rises with cumulative dose.
How Canthaxanthin works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Avoid — deposition adds a confounding retinal finding to a retina already under assessment.
Avoid — no safety data at tanning doses, and no reason to accept the exposure.
Avoid — no safety data at tanning doses.
Beta-carotene and canthaxanthin are often combined in tanning products; cumulative carotenoid load is what drives deposition.
Tip: Do not take it; the finding is dose-dependent
Tip: Do not take it — a fatal case is reported and the true frequency is unknown
Tip: Stop and seek ophthalmological assessment
Tip: Reversible on stopping
The current evidence for Canthaxanthin is insufficient to assign an evidence score, based on 4 indexed studies. A food-colouring carotenoid taken in high doses to bronze the skin. It works — and it deposits dose-dependent crystals in the retina, and a fatal aplastic anaemia has been reported in a healthy young woman who took it for tanning. Not approved as a tanning agent in the US or EU. Representative study: PMID 41890775.
The commonly studied dose of Canthaxanthin is No appropriate dose. This entry exists so the compound can be screened, not taken.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Timing is flexible for Canthaxanthin — consistent daily use matters more than the time of day. No dose is appropriate, so no timing guidance is given.
Canthaxanthin should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are crystalline retinopathy (crystals around the macula), orange discolouration of skin and stools, aplastic anaemia / bone-marrow suppression. Use caution if any of these apply to you: Anyone — a fatal aplastic anaemia is reported and no human safety study of oral dosing exists; Any existing retinal or macular disease; Anyone unwilling to have retinal deposition that may take two decades to clear.
Beta-Carotene
Mostly mechanism / observationalA plant pigment the body converts to vitamin A, sold for "natural tanning". It does not tan you — at high doses it turns skin orange-yellow. In smokers, two large randomised trials found it INCREASED lung cancer and death.
Tetrahydrocurcumin
Mostly mechanism / observationalThe main active metabolite of curcumin, sold as a colourless, more stable 'next-generation curcumin.' It's a genuine antioxidant and anti-inflammatory in the lab, but human evidence is almost non-existent — experimental, not a proven supplement.
Caffeine
Likely helpsBlocks adenosine receptors to boost alertness, reaction time, and endurance — one of the most proven ergogenic aids.
Adapalene
Mostly mechanism / observationalA modern topical retinoid for acne — now available over the counter (0.1%) as well as by prescription (0.3%). A drug, not a supplement or cosmetic. Adapalene is a third-generation retinoid selective for the retinoic-acid receptor beta; it normalizes how skin cells shed (comedolytic) and is anti-inflammatory. The honest framing: this is one of the best-evidenced acne treatments — a 5-trial meta-analysis and a 40-trial network meta-analysis show it matches tretinoin's efficacy with faster onset and notably better tolerability, and the adapalene-benzoyl peroxide combination is among the most effective regimens available. Caveats: it still causes retinoid irritation and slow onset, it is not superior to (only as good as) other retinoids, and — as a retinoid — it is generally avoided in pregnancy.
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Reviewed by Dr. Baher Al Hakim · Last reviewed August 2026 · evidence from 4 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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