Just find out you’re low in vitamin D? Or maybe it’s winter and you just miss the holy lightbulb in the sky?
Well, I bought, used, and tested the Sperti Sunlamp, and in this review, we cover everything you need to know before you make the big purchase.
Does the Sperti Vitamin D Sun Lamp Work?
Yes!
The Sperti vitamin D lamp is an FDA-approved class II medical device that has been proven to increase vitamin D levels.

There’s definitely enough UVB in this lamp to produce vitamin D!
In fact, Sperti conducted their own study to get FDA approval.
The Sperti Vitamin D Study
In this study, 5 participants with skin types 2 and 3, were irradiated for 5 minutes, 3 times per week for 4 weeks.
At the end of the study, all 5 subjects had an average increase in vitamin D levels of 47.5%.
Not bad! And since you can use the lamp more than they did in this study, these results can be improved upon!
How to Use the Sperti Vitamin D Lamp
Let’s go over the recommendations for using the Sperti lamp.
How Often Should You Use It?
During the first week, Sperti recommends using the lamp for 3 minutes every other day.
If this doesn’t cause you to burn, they recommend increasing this duration to 4 minutes during week two.
While on week three and beyond, the recommended exposure duration is capped at 5 minutes max.

While Sperti recommends alternating front and back on separate days, I see no mechanistic reason as to why you couldn’t do separate areas of your body on the same day should you wish.
How to Use the Lamp
Since the recommended distance is 15 inches, you’ll need to make sure you aren’t any closer than this.
When using the lamp on your front side, you can use your arm as a gauge of distance. Most people will find that while forming a fist, from your elbow to your fist is about 15 inches. So you can use this as a gauge.
However, since you can’t do this for your backside, an easier way may be to find a place where you can place the lamp 15 inches from the edge of a surface.
This way, you know that when you stand right at the edge, you’re in the right spot.
Are Vitamin D Lamps Safe?
Vitamin D lamps are safe if you use them for the recommended amount of time and don’t stand too close.
Just like the sun, you can damage your skin if you use the Sperti lamp too long, so don’t!
There are certain medical conditions and lifestyle behaviors that can increase your susceptibility to photodamage from ultraviolet light.
Some examples of things that can increase photosensitivity:
- Birth control
- Perfumes and lotions containing essential oils
- NSAIDS like ibuprofen
- Vegetable seed oil consumption
- and much more!
Here is a bigger list provided by Sperti in their product manual:
So just know that there are things you can and should be doing to improve your sensitivity to damage from the sunlight.
Who Can Use the Lamp?
In addition, Sperti warns that those with type 1 skin should not use their device. Think pale ginger, these are the Ron Weasly types.

This is because these folks have very little adaptation to ultraviolet light and should exercise caution when using a powerful lamp like the Sperti.
If you have a paler complexion, be sure to limit your exposure time and distance from the lamp wisely and watch for redness for 48 hours following use.
Does the Sperti Vitamin D Lamp Give You a Tan?
It’s not intended for tanning, and Sperti claims it will not tan your skin.
Though there’s certainly plenty of UVA in this lamp, which is the part of the sun primarily responsible for the tanning effect.
I suspect that it will produce a mild tan over time in some individuals who tan well.
The Benefits of a Vitamin D Lamp
There are many benefits to exposure to sunlight and ultraviolet light you may or may not be aware of.
As the authors of this study point out, exposure to sunlight is necessary for public health!
For one, exposure to UVB rays from the sun gives us our primary source of vitamin D! Many of us in the United States will struggle to produce enough throughout the year and could benefit greatly from a vitamin D lamp.
According to this study, it also appears as though UVB exposure on the skin helps modulate the gut microbiome! These are preliminary findings but they go to show us that there’s more at work here than we may know about.
We also produce natural opiates called endorphins when exposed to ultraviolet radiation, this is why being in the sun feels so good!
We also now know that ultraviolet exposure on the skin produces nitric oxide which helps a lot with blood flow.
Need I go on? The sun is a powerful and useful resource as long as you don’t burn yourself to a crisp.
The immense benefits of UVB and sunlight are summarized greatly in Dr. Holick’s book The Vitamin D Solution, which I highly recommend you check out!
Testing the Sperti Vitamin D Lamp
Of course, we put our UV spectrometer to the test here!
Spectral UV Light Output
I wanted to see how much UVB and UVA this puts out and where.
Here’s the spectral output:
As you can see, it mainly emits UV with a few spikes in the visible range. Here’s an output graph showing the relative output in mW/m2 at the recommended range of 15 inches:
UVB ranges from 280 to 315nm, while UVA ranges from 315 to 400nm; looking closer at the UV range, we can see that the Sperti is putting out about 42% UVB and 56% UVA.
There is plenty of UVB for vitamin D production, and the presence of UVA can help regulate this and contribute to the production of endorphins.
Flicker
I thought it would be worth checking the flicker as well, even though visual stimulus is not the goal of this product.
We detected a tiny ~2% flicker at 120 Hz, not too bad.
Magnetic and Electric Fields
Finally, I was curious about EMFs, so I also checked these using an EMF GQ-390.
Fortunately, there’s nothing to be found here. There is a magnetic field starting at around 6″ from the unit, but since you won’t spend any time in that range, it doesn’t matter.
EMF testing was done using the GQ EMF-390.
Should You Buy It?
Since the Sperti Sun Lamp comes with a 60-day money-back guarantee, there’s almost no reason not to try it out!
It’s portable, super easy to use, and it’s an excellent way to produce vitamin D and endorphins throughout the cold winter months.
If that doesn’t sell you on it, one look at Sperti’s trust pilot page will show you just how much users love this product!
Thank you Derek for your great work on this subject it is very appreciated. I have just bought a UVB light with the express intention to raise my VitD levels without use of supplement which do absolutely nothing for me. I suspect too that VitD is just one of the many benefits of Sun exposure. All my life I have suffered from winter problems such as mood and energy and skin and gut issue the list goes on. I am really hoping that the lamp will help. I wondered about the UVB/UVA issue and mix and if a tan is necessary for the health benefits I receive from the sun – I guess I will find out. The extra data from your testing was really useful, especially the UV vs distance measurement. I too thought about building one myself but need the health benefits badly so decided to as you say get the gold standard. Pls let me know how you get on with the self build and the parts you use. Also fascinated by vitD cofactors such as Mg, Cu maybe Zn and a few others Boron possibly and retinol. Tim
Great to hear from you Tim!
I resonate with that 100%, my gut isn’t perfect that’s for sure (who’s is?) and I suffer from mood problems in the winter due to lack of sunlight.
There are a number of benefits we derive from UVA exposure like nitric oxide production for example, as well as modulation of Vit D production.
I’ve finished building the DIY lamp and I’m currently running it through some tests, I’ll hopefully be posting it on the website in the future so look out for that!
Hi Derek – Thanks for the reply. I look forward to reading your build details and results cant wait. My suspicion for myself is that I have a (possibly genetic issue) with absorption or utilisation of D from foods and supplements. My maternal grandmother had the same health issues as me and I am now observing it with my eldest daughter. Of course my poor grandmother never got to the bottom of it sadly and suffered all her life with a confusing mix of non specific issues. My response to the sun is incredible, nothing comes close and yet I have dosed with D3 to the max with zero benefit. I will let you know how I get on with the light I am praying that it will work as I live in the UK and the UVB disappears in my estimation by the start of September and does not appear again til April. Too long lol!
I hope the light is a blessing to you too – let me know also. Tim
PS – can you give me details of the UV meters you used? Ta
I’ve definitely seen a lot of people who don’t seem to react well to oral vitamin d. I wish you the best of luck with the lamp!
I went ahead and updated the Sperti review with links to the meters used for testing. But they were the UVI, UVA, and UVB meters made by Solarmeter.
Thanks Derek appreciate the meter info. One more thing if I may – I wonder if you have thought about the safety implications of UVB exposure. From my research there does seem to be an interesting paradox with UVB and Vitd. On the one hand repeated and too much UV is clearly a danger in terms of cancer and aging of the dermis, but on the other hand vitd appears to be protective of skin health not only in terms of melanoma but also in skin condition and possibly also protection AGAINST sun burn. Additionally many many people seem to report improvements in skin health from just look and feel to more serious issues such as Psoriasis and vitiligo. The Sperti vit D lamp seems to promise no tan and no burn which would also strongly suggest its unlikely that there is damage to the skin – probably much more likely only benefit. I would be very interested in your comments. Also 5 mins per day every other day adds up to 15 hrs a year of exposure. I think some people might get that in a few days in some fortunate sunny locations. When I was a kid I could clock that up in a week on a Meditteranean hol lol!
Oh I’ve definitely taken a deep dive into the pros and cons of UV and sunlight exposure. It’s a bell curve for sure. Not enough and too much are both bad, I believe melanoma in particular doesn’t actually have a very strong association with sunlight, but some other ones do.
There’s also the fact that diet alone can significantly improve photo damage protection (i.e. seed oils), as well as infrared exposure.
But yeah! I don’t think there’s any risk to using a vitamin d lamp like to Sperti or the one I’ve made if you under your personal erythemal dose. And the added benefit of increased melanin over time (at least with the one I made since it has more UVA) will help you stay protected outside during higher UV index days.
Hi Derek
With reference to your excellent measurements on the lamp – how did you get from uw/cm2 to UVI? It looks from the graphs like 100uw is very approximately a UVI of 9? Not sure if there is a mathematical conversion. Could you shed some light on this lol! Tim
So this is just a matter of how the tools I used work. They aren’t perfect mind you, hopefully, in the future, I can get my hands on a real UV photo spectrometer to really see what’s under the hood.
You can take a look at Solarmeter’s page for the UV Index meter they sell for details on how it calculates its number. Since this isn’t the Sun, the results from these meters can’t really be compared to those from the sun, but it’s all we’ve got right now!
Hi Tim, just wondering whether or not you got a tan?
Since you stated you purchased for an increase in Vitamin D I assume you are a light/fair skinned man like me.
Hope to here from you & all the best, George
how much vitamin D does this generate if used daily for five minutes
According to Sperti’s study with five participants, they had an increase of 1,000 IU per day while using the lamp 3 times per week for around 4-6 minutes it looks like. Each exposure was around ~2300 IU.
Here’s a quote from the study with more info:
“At the end of the in vivo study, all five subjects had a significant increase in their serum 25(OH)D3 levels of approximately 10 ng/ml regardless of their baseline levels, and their 25(OH)D3 levels reached a plateau by week 3 of the study. This is equivalent to what was observed when healthy adults ingested vitamin D3 1000 IU/day or 7000 IU/week for 11 weeks (21). Because the subjects were irradiated three times a week, each UVB exposure provided an equivalent of ~2300 IU of vitamin D3. Koutkia et al. (9) exposed a patient wearing a one-piece bathing suit for 10 min, three times a week to UVR from a tanning bed (~54% of the body surface area), and in 4 weeks, her 25(OH)D3 levels increased by 357% from 7 to 32 ng/ml. Our subjects experienced an average 47.5% increase in 25(OH)D3 levels with only ~9% of the total body surface area being exposed to UVR.”
THANK YOU! I had no idea this was even a thing and just added one of these to my SAD arsenal.
My winter issue is more dopamine/vitamin D than serotonin/sunlight so the lamps don’t do much, though I do use them for normal home/office lighting. In past years, I’ve VERY RELUCTANTLY resorted to tanning beds in the depth of winter and it was always miraculous, but the low pressure beds with UVB bulbs have all but disappeared. Hopefully this little gem that looks like a veterinary medicine device from the 80s will keep my levels up.
You’re very welcome Nova 🙂 I hope it works out well for you!
how does the UVA UVB irradiation compare to that of the sunlight?
I mean, If I wait for midday sun and get 20 minutes of it, and do this daily, I will not burn or tan. Yet, you can do just a couple of minutes of such a light (Sperti or DYI) every other day to stay safe.
I am very new to this subject and I need a solution in winter, so I am trying to understand what I am getting in to.
Any light on this topic will be highly appreciated.
Thanks
Hi Gustav! One of the big differences is the presence of infrared in natural Sunlight which can help offset some of the UV damage.
But as for a direct comparison of the UV range I don’t currently have that… something I’m working on!
The actual comparison would of course also depend highly on location and season. We are getting some new equipment soon that will allow us to take much better solar UV measurements so this will be added to the site in the future.
How can I find FDA information on this lamp?
What kind of information are you looking for? An approval letter or something?