There are those lamps like e.g. "ReptiGlow" for pet reptilians, to keep them healthy, the output being graded e.g. by habitat: jungle (trees somewhat reduce the UV that hits the animals), or desert (full sun exposure). Alas, I have found nothing about the exact wavelengths those kind of lamps produce, and the exact wavelengths human skin needs to produce vitamin-D.

The example used, "ReptiGlow", claims to mimic the UV mix of the sun, with the same kind of UV-A, UV-B mix.

Can such reptilian lamps actually be used to effectively produce vitamin-D in humans, e.g. countering European Winter, without harmful side effects? If generally so - how would one determine the needed exposure (lamp output, distance to skin, exposure time)?

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    Is this just academic curiosity? Why would anyone consider (mis)using devices of doubtful safety when obtaining sufficient vitamin D safely is trivially simple?
    – Carey Gregory
    Commented Dec 9, 2018 at 0:14
  • General curiosity. The idea came from me reading about how UV lamps were used to prevent rickets in children in winter, in the past. Not that common anymore. I haven't looked into this topic for a while, but from what I remember, for a long time a widely held opinion was that obtaining vit-D via skin was superior to food sources in some ways. Commented Dec 10, 2018 at 21:43

2 Answers 2


In short: UV bulbs for reptiles and tanning beds emit mainly UV-A, which does not promote vitamin D synthesis but can promote skin cancer.

UV light and vitamin D synthesis (Skin Cancer Foundation):

Our bodies manufacture vitamin D when the sun's ultraviolet B (UVB) rays interact with 7-dehydrocholesterol (7-DHC) present in the skin. However, we can produce only a limited amount of vitamin D from UVB. A few minutes at midday are sufficient for many Caucasians...After reaching the production limit, further exposure actually destroys the vitamin, decreasing vitamin D levels.

Wavelengths of various ReptiGlo bulbs range from 300-640 nm (only UV-A or both UV-A and UV-B), depending on the model; the bulbs have up to 40 Watts (Exo-terra.com).

Modern tanning devices provide mostly UV-A (315-400 nm); the power is 100-200 Watts (Wikipedia).

FDA.gov claims that both UV-A and UV-B rays causes DNA damage, which can lead to skin cancer and that all use of tanning beds increases the risk of skin cancer, from which one can conclude that the UV reptile bulbs could do the same.

According to Indoor Tanning (American Academy of Dermatology):

  • Exposure to UV radiation from indoor tanning devices is associated with an increased risk of melanoma and nonmelanoma skin cancer, including squamous cell carcinoma and basal cell carcinoma.
  • Using indoor tanning beds before age 35 can increase your risk of melanoma, the deadliest form of skin cancer, by 59 percent.

I don’t know if they can be used, but they shouldn’t. Recently, sun exposure is considered more and more harmful to the skin. This is why for recommended Vitamin D levels, no sun exposure whatsoever is usually assumed, and only intake via diet considered.

Because ultraviolet rays from the sun and tanning beds can cause skin cancer, the American Academy of Dermatology does not recommend getting vitamin D from sun exposure or indoor tanning.

Source: American Academy of Dermatology

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    Hm, I've read about conflicting studies, some claim that some amount of sun exposure is inversely correlated to development of melanoma. Tanning beds are geared towards tanning / producing UV-A, which is the band said to cause cancer(?). Some reptilian lamps output a high UV-B portion (they claim), i.e. the exposure time (to get vit-D) may be reduced, also reducing the exposure to UV-A. So much for theory. Actual numbers would be nice, but given the weirdness of my question, I guess it requires some luck that someone knows about both, human skin requirements and pet accessories ;) Commented Dec 8, 2018 at 15:11
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    @user1847129 Do you have those studies at hand? I can’t imagine the evidence to be conflicting, but I can‘t criticise studies I haven’t read yet either... UV-A and UV-B are definitely both harmful and exposure time of both kinds is directly proportional to developing melanomas. If an institution like the AAD does not even recommend sun exposure for vitamin D production, I think it is safe to assume that the studies are pretty comprehensive and non-conflicting.
    – Narusan
    Commented Dec 8, 2018 at 15:24
  • @user1847129, the last paragraph of this PubMed article says that sun exposure increases the risk of melanoma in people with sun-sensitive skin types (pale skin, fair hair) and decreases the risk in non-sun-sensitive types. And there are two other common skin cancers: squamous cell and basal cell carcinoma, which are related to sun exposure.
    – Jan
    Commented Dec 28, 2018 at 13:37

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