Reviewing the sperti vitamin d lamp featured image

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?


The Sperti vitamin D lamp is an FDA-approved class II medical device that has been proven to increase vitamin D levels.

sperti sunlamp spectrum
The section on the left is the UVB that helps you produce vitamin D. (Source)

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%.

a screenshot of sperti's vitamin d study in which they state all participants showed a 47.5% increase in vitamin d levels on average

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.

sperti lamp directions
Directions from the Sperti vitamin D lamp user guide (Source)

It’s important to note that this 5-minute limit only applies to the part of the body you’ve irritated.

Sperti themselves claim that you can do both front and back.

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:

a large list of things that can increase photosensitivity to ultraviolet light

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.

fitzpatrick skin types
The Fitzpatrick skin type chart. (Source)

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? As long as you don’t burn yourself to a crisp, the sun is a powerful and useful resource.

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

I want this review to be thorough, and since I’ll be making my own vitamin D lamp, I’ve taken some measurements of the Sperti lamp and varying distances to see what we’re working with.

UV Index

The first thing I wanted to know was roughly what the UV Index was at various distances from the lamp.

For this, I used the UV Index meter from Solarmeter.

At around the recommended 15″ from the grate, the UVI is around 14, which is about the max you’d see at the equator, so it’s no wonder 5 minutes is the max!

As you can see in the graph below, if you’re a bit sensitive, you can back up to where the lamp’s UVI is lower.

a chart showing the uv index per inch from 10 inches to 50 inches from the bulbs

As you can see the UV index rises sharply the closer you get, it jumps up to around 22 at 1 foot. So be careful not to get too close for too long!

Here’s a link to the data we collected if you’d like to check it out for yourself!

  • Learn more

You can check out my DIY vitamin D lamp build where I compare the results to the Sperti lamp.


Next, I wanted to know what the ratio of UVA to UVB was, again, roughly speaking.

I used a UVA and UVB meter from Solarmeter.

From the measurements I got, it looks as if there’s just a bit more UVA than UVB.

sperti uva and uvb per inch

This makes sense since in Sperti’s study, their spectral graph shows more UVA than UVB.

Magnetic and Electric Fields

Finally, I was curious about EMFs, so using an EMF GQ-390, I checked these as well.

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 be spending any time in that range, it doesn’t really 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.

And if that doesn’t sell you on it, one look at Sperti’s trust pilot page will show you just how loved this product is by its users!

Sperti Vitamin D Lamp



  • Proven to increase vitamin D in clinical trials
  • 60-day money-back guarantee
  • Extremely easy to use


  • Large upfront cost
  • Only radiates part of your body at once

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  1. 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

    1. 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!

  2. 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

    1. 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.

  3. 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!

    1. 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.

      1. 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

        1. 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!

    1. 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.”