DIY vitamin d blog post featured image

Worried about Vitamin D deficiency or seasonal affective disorder? Looking for a cheaper alternative to the Sperti sun lamp?

In this guide, I’ll walk you through step by step how to build your own vitamin D lamp!

  • Does It Work?

I’ve officially finished the DIY build, and it works! See later in this guide for details on my regimen.

vitamin d test results

Since this setup also emits UVA, it should also be able to function as a tanning lamp for those of you looking for that.

Why Did I Build This?

I live in Michigan, so for several months of the year, the sun is too low for vitamin D production.

Why not use the Sperti lamp? Well, this DIY lamp is cheaper, emits more UVB, and it appears safer.

Explaining the UVB to UVI Ratio

You see, reptile owners have done a lot of UVB light testing. And they’ve discovered a simple metric to determine how safe a UVB light source is.

This is the UVB:UVI ratio.

It’s a proxy measurement, but it’s a very useful one.

This ratio tells us roughly how much short-wavelength radiation is present in a light source, without using a $3,000 UV spectrometer (which I don’t have). Please Santa.

Here’s how we figure this out:

At a set distance, say two feet, you measure the UV index and the total UVB in uW/cm2.

uv meter measurement ranges compared to sunlight
UV meter measurement ranges relative to natural sunlight

As you can see above, the UVB meter detects longer wavelength light than the UVI meter.

If we get a UV index reading of 14 and a total UVB reading of 200 this gives us a ratio of 14.3, while if our total measured UVB was 350 at the same UV index, the ratio would be 25.

A lower ratio is indicative of there being more short-wavelength UVB than long-wavelength.

This is bad because natural sunlight doesn’t go much past 300nm, while lamps like the Sperti go down well into the 250-270nm range.

Here are the average UVB to UVI ratios for the Sperti lamp vs the DIY light I built:

  • Sperti: 10.3
  • DIY: 25.7

As you can see, the Sperti lamp is producing far more short-wavelength UVB light than our DIY lamp.

So in other words, at a UVI of 14 (where you are recommended to use the Sperti), both lamps have a drastically different amount of UVB.

  • Sperti UVB at UVI of 14: 130 uW/cm2
  • DIY UVB at UVI of 14: 360 uW/cm2

So you’re able to get exposed to almost 3x more UVB radiation at the same UV index. This is because the Sperti lamp is pushing out more short wavelength UVB, which is sending that UVI up.

It’s unclear if the DIY light will be more effective, but it’s likely that it will be, on top of that, because it has significantly less short wavelength UVB radiation, it will be a lot safer to use long-term.

Hopefully that all made sense.

Let’s build this thing!

The Parts You’ll Need to Build it

First, let’s go over the parts we’ll want to pick up to build our lamp.

Fluorescent UVB Lights

The most important part of this build is of course the lights. For these, I went with the 46″ Dragon D3 made by Arcadia. However, there are other options out there which I’ll link to below.

I’ve selected this light because it has the highest output UVB I could find at the time and Arcadia makes some pretty high-quality stuff.

They’re also quite large at 4 feet so we’ll be able to cover far more surface area than the Sperti lamp.

Arcadia 46″ 14% UVB Bulbs

arcadia uvb light product photo

You’ll need four of these total to fill up the light fixture below.

ReptiSun 46″ 10% UVB Bulbs

reptisun uvb lamp product photo

Here’s an alternative that can be purchased on Amazon if that’s more your style.

Note: I didn’t test these in my setup, but they should work just fine, ZooMed is a reputable brand.

AgroMax 75% UVB T5

75% uvb bulb

A reader of ours found this 75/25 UVB/UVA bulb! If you’re more interested in a pure UVB bulb this might be worth trying out!

Grow Light Fixtures

The fixture I used in this project was a 4-foot 4-bulb version explicitly built for 54w fluorescent T5-HO bulbs. However, you can get one-bulb or two-bulb versions as well if you’d like to try something less powerful.

4 Bulb T5 Light Fixture

vivosun 4 bulb fixture product photo

You don’t have to fill this whole thing if you don’t want to, you could just use two bulbs instead of all four.

2 Bulb T5 Light Fixture

2 bulb fixture product photo

1 Bulb T5 Light Fixture

one bulb fixture product photo

It does come with 4 bulbs of its own that we won’t need, so you can recycle those if you want. I’ve been unable to find a fixture that doesn’t come included with lights.

The Protective Screen

The one possible downside to this setup is that it doesn’t come with a protective grate, which is nice to have because fluorescent UVB bulbs utilize mercury. You don’t want to break these bulbs.

If you live alone and aren’t worried about anyone breaking it, you can always skip this part.

The best option I’ve been able to come up with is attaching a metal wire mesh to the front.

mesh screen product photo

1/2 Inch Galvanized Welded Wire Mesh

This mesh is quite stiff and will work well to protect the lights.

zip tie mounts product photo

Adhesive Zip Tie Mounts

You’ll need something like this to attach the mesh to the light fixture.

Building the Vitamin D Lamp

Okay, now let’s put it all together!

Preparing the Light Fixture

Here’s what you’ll need to do with the fixture.

  1. Remove the blue protective film from the reflective trays, this is pretty easy.
  2. Play around with fitting the trays into each other, they come a bit loose but once you play around with them for a bit you’ll figure out how they fit together.
  3. Clean up any smudges.

Installing the Bulbs

Now carefully pull the bulbs out and install them one by one, these are bi-pin lights, so the connectors on either side install vertically into the fixture.

You may have to push the light fixture connecter out on one end to get the light pins to fit into the slot.

Once it’s sitting in the slot on both ends and is pushed down all the way, you can spin it to the right to lock the light into place.

Now repeat for all four lights!

Mounting it on the Wall

To mount the light on your wall of choice, you’ll want to start by installing a hook or screw of some kind into a stud at around 70″ off the floor.

Next, you’ll hang the light using one of the hooks it came with.

closeup image showing hook attachment to screw in stud
Just like that! Don’t mind the crack in the wall, it’s not that heavy, that’s just my amazing drywall work.

I also went ahead and attached the bottom to the wall using a couple of 3M sticky pads.

Here’s what the finished product will look like:

the diy vitamin d lamp fully installed on the wall

Not bad!

Installing the Protective Grate

Now for the protective grate, should you want it…

You’ll need tin snips for this part!

Cut off a 49″ long section of the mesh, and begin to make it flat so it’s easier to work with.

Next, place the mesh against the panel and start bending the top portion over, it’s pretty stiff and tough mesh so this isn’t the most effortless process.

Once you have the top done, you can move on to the sides.

The trick here is to bend the sides just a bit, near the top, so that you know where it will need to be bent all the way down.

Once you have a reference point, take the mesh off and bring it over to a flat surface with an edge (like a table or counter), and bend the mesh all the way down on both sides using that edge, it’s much easier this way than trying to do it on the lamp.

  • Tip

Make your bends just a bit more than 90 degrees, this way once it’s attached to the light, the metal won’t want to pull away from the zip-tie mounts.

Once it’s all bent to shape, you can cut out the corner sections that aren’t needed.

closeup view demonstrating the cut corners of the mesh
Example of how the corners will look once you’ve cut them to shape.

And that’s about it! It’s a little bit of a pain, but once it’s done it’s done.

Just stick your zip tie mounts onto the light and start zipping the mesh into place!

Testing the DIY Light

  • Testing Information

I hope to purchase a professional UV spectrometer (>$2000) one day to improve this testing, in the meantime, this is the best I’ve got.

I used the UVA, UVB, UVC, and UVI meters from Solarmeter to test this light setup.

As soon as I began, I realized it was going to be a little challenging, because, unlike the Sperti lamp, this one ramps up to its max within the first 2-3 minutes (if it’s warm).

the uv index over time at 25 inches from light
UV Index @ 25″ over a 15-minute time span

As you can see, it then slowly comes down to baseline over the next 15 minutes or so.

It’s a bit harder to compare the two because of this.

But I tried anyway.

UV Index Measurements

As you can see from the graph below, this DIY lamp is quite a bit more powerful than the Sperti lamp:

sperti uvi vs diy uvi bar graph
UV Index of Sperti lamp vs DIY lamp

This means that while you get a UVI of 14.3 at 15″ from the Sperti, the same UVI is reached at 24″ for this light.

If you’d like to take a deeper dive into the measurements for this light as well as the Sperti, the Google Sheets document can be found here.

  • Learn more

You can read our review of the Sperti vitamin D lamp here if you’re interested.

UVA Measurements

Since the UVI pretty much only takes into account UVB and lower, what about UVA?

Well, the DIY light puts out way more UVA than the Sperti light does.

bar graph of uva from sperti lamp vs uva from diy lamp
It produces boatloads more UVA than the Sperti lamp

Is this a good thing or a bad thing though?

Well, natural sunlight does produce quite a bit more UVA than UVB, so this seems to mimic sunlight in that regard better than the Sperti.

Of course, this can also double as a tanning lamp as well if you spend more time in front of it.

You may not want this much UVA, perhaps you’re only interested in the UVB aspect, if that’s the case you’ll want to skip this. I’ll see if I can create an affordable narrowband UVB light in the future.

Does UVA Affect Vitamin D Production?

Kind of.

In this study, in which 75 participants total finished. The researchers compared vitamin D production in 4 groups.

UVB only, UVA only, UVB+UVA, and a control.

It was observed that almost no differences were seen in the full spectrum UVA+UVB group when compared to the UVB-only group.

uva and uvb vitamin d study screenshot

In fact, the full spectrum group actually had a higher mean change in serum D3 than UVB only.

They do note that under longer duration times (≥9 min) UVA may decrease pre-vitamin D3 production. Which is fine, UVA does act as a D3 modulator in nature.

So I don’t think there’s anything to worry about here. In fact, it’s likely a good thing as UVA is useful for nitric oxide production, blood flow, and increasing endorphins.

UVB LED Options

Several studies have shown that UVB between 293-295nm is the most effective at triggering the production of Vitamin D. However natural sunlight has almost no light in this frequency range so I have concerns with trying to emulate this…

It’s not easy to find UVB LED products on the market just yet, but here are some of the options I’ve found so far:

Zoo Med ReptiSun UVB LED

reptisun uvb led

This might be the most legit UVB reptile light out there right now since they actually provide a spectral graph report:

reptisun uvb led spectrum graph

Looks like around 306nm LEDs for the UVB portion which may or may not work well, I’m not sure.

I’d try using these for a minute at 1-2 feet away to start? But I haven’t tried them myself yet.

Here’s an in-depth report I found.

Aiicioo Reptile LED UVB Light

Aiicioo Reptile LED UVB Light

I’m not sure what wavelength these UVB LEDs are but they’re a bit larger than the ReptiSun so the coverage might be a bit better.

The wattage still maxes out at 9w so overall they should be similar in output.

Chroma D-Light

chroma vitamin d light

By far the most expensive Vitamin D light on the market, but probably the most legit, safe, and effective way to get vitamin D there is.

The combination of red and Near-IR combined with narrowband 297nm UVB LEDs make this a powerhouse.

Use coupon code OYB5 for 5% off!

How to Use Your Vitamin D Lamp

Okay, so it’s built, and mounted, and you’re ready to stand naked in front of it.

But how far away? And for how long?

The Warm-up Period

You’ll see the lamps aren’t evenly lit up when first turning it on, they take a few minutes to fully warm up.

So wait until they are uniformly lit to use the lamp.

How Far Away Should You Stand

I currently use my lamp at a distance of around 14-16 inches.

I’d start at two feet for safety.

  • Tip

Grab a pair of UV glasses before using this!

How Long Should You Use the Light

How you react to ultraviolet radiation depends on your personal situation.

Getting my vitamin D from 23 ng/dL to 39.2 took about a month, and I spent about 10 minutes per day in front of my lamp about 5-6 days a week on average.

Depending on your skin type, diet, genetics, and all the rest, the time to erythema will vary.

Erythema is, for those that don’t know, just reddening of the skin. If your skin is getting very red, you’re standing too close for too long.

Simple as that.

Didn’t get red at all? Feel free to increase the time or stand a little closer. Just only change one variable at a time so you know what is and isn’t working for you.

The Best Time for UV Exposure

The best time to use this would be in the middle of the day, preferably after some infrared exposure, as infrared is protective against UV damage.

For most, the best routine would be to use some kind of infrared light therapy in the morning, followed by a UV light session when they get home from work.

You don’t really want to expose your skin to UV first thing in the morning because it’s very unnatural. I would think this might harm your skin and potentially cause problems with circadian timing and hormone rhythmicity.

Alright, that’s it!


I’ve personally used the Sperti and I can confidently say that my DIY sun lamp feels much better.

It feels warm and powerful like the sunlight I’m so fond of standing underneath when I can.

Hopefully, this has inspired you to build your own!

Leave a Reply

Your email address will not be published. Required fields are marked *


  1. Hi Derek,

    Thanks for this great writeup!

    I want to avoid tanning as much as possible while increasing my vitamin D levels, so will need to go the higher UVB bulb route. I live in the UK and it appears the AgroMax bulb is not available here, however I have found this:

    “System Output 75% UVB and 25% UVA, Spectrum peak at 310nm (UVB)”

    It appears it comes with a case/reflector, or whatever you call it, for each bulb and they say you can “daisy chain” them together, so I assume you shouldn’t need one of those 4 bulb holders.

    However it appears to only be 22 Watts

    I’m afraid I don’t know my arse from my elbow when it comes to this stuff. The lights you’ve recommended are 54 watts, so more than double the power. However, if I understand correctly, they produce less UVB as they’re only 14% UVB. Since these produce more UVB, 75%, but are less than half the power, would your setup and my hypothetical setup potentially be not that far off eachother in terms of the amount of UVB being produced, could these 22W 75% UVB bulbs possibly even output more UVB than the the 54W 14% UVB bulbs? Or am I completely missing the mark here.

    Any guesswork is still much appreciated as I don’t know what I’m talking about.

    1. Hey Dave! You can certainly give those a shot, they’ll work!

      But unfortunately comparing them without testing side by side is impossible. When it comes to UVB specifically, the amount of power output in certain wavelengths makes a big difference. For example saying 75% UVB vs 14% UVB isn’t accurately telling us how much power is in each wavelength within the UVB range itself.

      So for wattage and even percentage you can’t do an apples to apples on these since the power ratios within the UVB:UVA bands themselves differ.

      These lamps will be very powerful so just be careful with them! Start far away and with short durations.

      1. Thanks for the advice 👍

        Just had another look, they appear to be 18W not 22W

        They’ve got an image of the spectrum here, not sure if that provides any additional clues:×500.jpg

        And a comparison to other similar products (it seems similar to the Agromax):×500.jpg

        1. That’s probably similar to the actual spectrum, I’ve just learned not to trust manufacturers data at this point 😅

          Hard to say for sure how these compare to others at this point other than they’re likely very high in UVB.

          1. Wangled something together with a cardbord box, here’s my temporary setup for now until I build something better:

            This thing is no joke. A couple of days ago at noon, I did 4 minutes on chest and back for a total of 8 minutes at a distance of 16 inches. I could feel pleasurable sensations while it was radiating on my back.

            I wasn’t expecting any immediate effect, but after my session, I felt rather giddy and felt good throughout the day, with more energy, focus and mood was upbeat. It was a very potent and obvious effect throughout the day.

            In the evening however, I started feeling almost manic and a bit on edge and found it hard to stay still. My sleep that night was patchy and I woke up pretty exhausted.

            I’ve experimented rather extensively in the past with tyrosine and other dopaminergic things, and I’d say a lot of the effects I was having were probably consistent with increased catecholamines. There was definitely some dopamine / norepenephrine stuff going on.

            The next day, I was curious to see if anyone experienced borderline mania from a Vitimin D lamp and did some Googling, I found a couple of people experiencing intense stuff from the Sperti:



            So I’m going to take this really slow, I think this DIY lamp is more powerful than the Sperti. Will probably wait until next week to try it again and only try it for a couple of minutes this time and gradually work my way up. I will also start out with an infra-red session this time, I skipped that when I tried it the other day.

          2. Thanks for the update Dave! Wow yeah I’ll bet that is more powerful than the Sperti. You may have even gotten an overdose of vitamin D! Haha

            Increasing the distance and/or decreasing exposure time should help. Could very well be that the higher UVB output with that duration and distance is resulting in too much too fast.

  2. Hey Derek, This was super informative. I live in Minnesota, and definitely suffer from lack of sun & vitamin D. I have a tanning club membership, but I also have a lot of skin issues, which in turn lead to me being somewhat reclusive during the winter months (my skin totally clears up if I go on vacation to Hawaii, or spend a lot of time in the sun, or the tanning booth). I was wondering if you had any thoughts on the single round bulbs as opposed to the long tubes (if I was only wanting to target my face on days I didn’t want to go out)? I know this might sound strange, but it has been a huge insecurity for me all of my life, and tanning has literally been h the only cure…

    1. Hi Kristine! I don’t have any specific recommendations at this time but that’s something i’ll be working on over this next season!

      Are you referring to bulbs like this? Or this? They should work, you’ll just want to but them in a reflector dome and wear eye protection.

      1. Yes, I was thinking more in terms of the second one… but would one be better than the other? And by a reflector dome, do you mean a fixture where the bulb is enclosed, like this:

        PewinGo Reptile Heat Lamp, Lamp for Aquarium Turtle Tank with 25w+50w Basking Spot Light Bulbs and 360° Swivel Clamp for Turtle, Snake, Lizard, Cockatoo, Chameleon Etc, Yellow


        I truly appreciate your expertise in this, as it’s hard to find this sort of info. Thanks so much!

          1. Derek this is such an awesome DIY! I appreciate you so much for taking the time to do this extensive research…and then sharing it with the world! Thank you so much, Monica

        1. Thank you so much for your advice! I will try these and give you an update… not sure if anyone here has issues like me… but like I said previously, I was looking for something I could use at home when I was not feeling up to going out in public (when my skin is acting up and looks horrible) & using my “tanning membership” (and because I pay for the “top-of-the-line” monthly membership in Minnesota… I really hate to buy one of those Sperti units… although I’m sure they are high quality…) Sadly I have suffered from horrible acne since my adolescent years, and despite multiple treatments over DECADES… nothing has worked except sun and ocean water. So… I have ordered a light and holder, and will update you on my progress. Thank you so much your advice. May the Sun Gods Bless You 🔆
          ~Jackie Kristine

          1. Hi Jackie Kristine!
            I am very much interested in how this works out for you as well. Please keep us posted!

  3. Thanks for this perfect article, will build one soon! I see you writing about negative ions somewhere else. Could you shine a quick light on your experience with these, do you have experience with generating them at home?

    1. Hi Roman! I’ve dabbled a bit in negative ions and definitely think they’re worth exploring personally. They do seem to positively affect mode and even circadian regulation in many studies I’ve looked into.

      Unfortunately there aren’t a ton of commercial products for healthy negative ion production. We own a few TEQOYA products which are really the best you can get and we really like them, they definitely help to clean the air and improve the atmosphere in our house.

        1. Dust certainly collects around the ion generators, so I know it’s helping cut down on the air particulates. I’ve seen many studies that show mood improvements from negative ion inhalation but we do a lot here to improve mood such as light, biophilia, etc. so it’d be hard to isolate if they’re having an effect that regard.

          We do feel great in our home though I can tell you that much!

  4. Love this content by the way, it’s some great information. Do you actually need uv glasses? Would you not want to mimic what it’s like if you were walking in the sun and it shining in your eyes or is the problem that we have to be so close to these lamps?

    1. I would say the amount of UV light coming from these is extraterrestrial in its strength, so it’s not really mimicking sunlight… If we could really mimic the Sun I wouldn’t be as worried.. But that would require implementing visible light as well as the full range of near infrared, and then making sure all of those are in-line with the wavelength ratios and strength of real sunlight.

      For now I’d say were best staying on the safe side 😀

      1. Haha ya better safe than sorry 😂 so would you even be able to get away with not buying uv glasses if you don’t directly look at the light, as in if you were looking around the light? I’m guessing the amount of uv light is still way too strong to even consider not wearing them

        1. You might be fine if you just closed your eyes? Eyelids block pretty much all of the short wavelength light, hence the red color you see through them. But don’t quote me on that lol

          You only get two eyes though! Probably better safe than sorry.

  5. HI there. Thank you for this valuable info. I’m interested in buying the AgroMax 75% UVB T5 because it looks like it has UVA and UVB. Its seems pretty powerful. Should I only get the one light and single fixture or will the 4 light/4 fixture set up safe for the short amount of time?

    1. Hi Gina!

      Just so we’re on the same page, the Arcadia bulbs I used to emit lots of UVA as well as UVB. The AgroMax bulbs differ as they emit far more UVB.

      One bulb may be enough, those are very powerful! So if you did a 4 bulb you’d just want to make sure you’re far away and using them for short periods.

  6. It might be possible to desolder the UVA led on the Zoo Med ReptiSun UVB LED and replace it with a resistor of similar voltage drop.

    This would allow for a vitamin D lamp that only uses UVB instead of UVB and UVA.